Soma Compound with Codeine

Muscle Relaxants, Centrally Acting, Combination
Opioid Agonists and Other Drug Combinations

Oral Administration

Administer with food to minimize gastric irritation.
Limit use to 2 to 3 weeks.
Storage: Keep aspirin; carisoprodol; codeine secured in a location not accessible by others.
Disposal: Mix (do not crush) medicine with an unpalatable substance (e.g., dirt, cat litter, used coffee grounds), place in a sealed container, and throw away in the household trash when it is no longer needed if a drug take-back option is not readily available.

Severe

seizures / Delayed / Incidence not known
GI bleeding / Delayed / Incidence not known
GI obstruction / Delayed / Incidence not known
peptic ulcer / Delayed / Incidence not known
hematemesis / Delayed / Incidence not known
GI perforation / Delayed / Incidence not known
intracranial bleeding / Delayed / Incidence not known
pancytopenia / Delayed / Incidence not known
interstitial nephritis / Delayed / Incidence not known
renal failure (unspecified) / Delayed / Incidence not known
anaphylactoid reactions / Rapid / Incidence not known
bronchospasm / Rapid / Incidence not known
neonatal opioid withdrawal syndrome / Delayed / Incidence not known
respiratory arrest / Rapid / Incidence not known
Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS) / Delayed / Incidence not known

Moderate

ataxia / Delayed / Incidence not known
depression / Delayed / Incidence not known
sinus tachycardia / Rapid / Incidence not known
orthostatic hypotension / Delayed / Incidence not known
gastritis / Delayed / Incidence not known
melena / Delayed / Incidence not known
elevated hepatic enzymes / Delayed / Incidence not known
constipation / Delayed / Incidence not known
leukopenia / Delayed / Incidence not known
physiological dependence / Delayed / Incidence not known
psychological dependence / Delayed / Incidence not known
withdrawal / Early / Incidence not known
respiratory depression / Rapid / Incidence not known
infertility / Delayed / Incidence not known
impotence (erectile dysfunction) / Delayed / Incidence not known
adrenocortical insufficiency / Delayed / Incidence not known
hyperalgesia / Delayed / Incidence not known

Mild

drowsiness / Early / Incidence not known
syncope / Early / Incidence not known
agitation / Early / Incidence not known
vertigo / Early / Incidence not known
tremor / Early / Incidence not known
irritability / Delayed / Incidence not known
miosis / Early / Incidence not known
insomnia / Early / Incidence not known
dizziness / Early / Incidence not known
tinnitus / Delayed / Incidence not known
headache / Early / Incidence not known
flushing / Rapid / Incidence not known
anorexia / Delayed / Incidence not known
vomiting / Early / Incidence not known
nausea / Early / Incidence not known
abdominal pain / Early / Incidence not known
stool discoloration / Delayed / Incidence not known
purpura / Delayed / Incidence not known
pruritus / Rapid / Incidence not known
rash / Early / Incidence not known
gonadal suppression / Delayed / Incidence not known
amenorrhea / Delayed / Incidence not known
libido decrease / Delayed / Incidence not known

Accidental exposure, alcoholism, depression, opioid overdose, opioid use disorder, potential for overdose or poisoning, requires an experienced clinician, substance abuse

Opioid use requires an experienced clinician who is knowledgeable about the use of opioids and how to mitigate the associated risks. Opioids expose users to the risks of addiction, abuse, and misuse, which can occur at any dosage or duration. Although the risk of addiction in any individual is unknown, it can occur in persons appropriately prescribed an opioid. Addiction can occur at recommended dosages and if the drug is misused or abused. Assess each individual's risk for opioid addiction, abuse, or misuse before prescribing an opioid, and monitor for the development of these behaviors or conditions. Risks are increased in persons with a personal or family history of substance abuse (including alcoholism) or mental illness (e.g., major depression). The potential for these risks should not prevent the proper management of pain in any given individual. Persons at increased risk may be prescribed opioids but use in such persons necessitates intensive counseling about the risks and proper use of the opioid along with intensive monitoring for signs of addiction, abuse, and misuse. Abuse and addiction are separate and distinct from physical dependence and tolerance; persons with addiction may not exhibit tolerance and symptoms of physical dependence. Opioids are sought by drug abusers and persons with addiction disorders and are subject to criminal diversion. Abuse of opioids has the potential for overdose or poisoning and death. Consider these risks when prescribing or dispensing opioids. Strategies to reduce these risks include prescribing the drug in the smallest appropriate quantity. Keep opioids out of the reach of pediatric patients, others for whom the drug was not prescribed, and pets as accidental exposure or improper use may cause respiratory failure and a fatal overdose. Accidental exposure of even a single dose of an opioid, especially by younger persons, can result in a fatal overdose. Because the risk of overdose increases as opioid doses increase, reserve titration to higher doses of an opioid for persons in whom lower doses are insufficiently effective and in whom the expected benefits of using a higher dose opioid clearly outweigh the substantial risks. Do not use immediate-release opioids for an extended period unless the pain remains severe enough to require an opioid and for which alternative treatment options continue to be inadequate. Many acute pain conditions (e.g., pain occurring with surgical procedures or acute musculoskeletal injuries) require no more than a few days of an opioid. Clinical guidelines on opioid prescribing for some acute pain conditions are available. Discuss the availability of naloxone with all patients and consider prescribing it in persons who are at increased risk of opioid overdose, such as those who are also using other CNS depressants, who have a history of opioid use disorder (OUD), who have experienced a previous opioid overdose, or who have household members or other close contacts at risk for accidental exposure or opioid overdose.

Asthma, chronic obstructive pulmonary disease (COPD), coadministration with other CNS depressants, cor pulmonale, hypoxemia, nasal polyps, respiratory depression, respiratory insufficiency, sleep apnea

Aspirin; carisoprodol; codeine is contraindicated in persons with significant respiratory depression and those with acute or severe asthma in an unmonitored setting or in the absence of resuscitative equipment. Aspirin; carisoprodol; codeine is also contraindicated in persons with the syndrome of asthma, rhinitis, and nasal polyps; aspirin may cause severe urticaria, angioedema, or bronchospasm. Avoid coadministration with other CNS depressants when possible, as this significantly increases the risk for respiratory depression, low blood pressure, and death. Reserve concomitant prescribing of these drugs for use in persons for whom alternative treatment options are inadequate; if concurrent use is necessary, use the lowest effective dosages and minimum treatment durations needed and consider prescribing naloxone. Monitor closely for signs or symptoms of respiratory depression and sedation. [61143] Persons with chronic obstructive pulmonary disease (COPD), cor pulmonale, respiratory insufficiency, hypoxemia, hypercapnia, or preexisting respiratory depression are at increased risk of decreased respiratory drive even at recommended doses. Persons with advanced age, cachexia, or debilitation are also at an increased risk for opioid-induced respiratory depression. Monitor such persons closely, particularly when initiating and titrating the opioid; consider the use of non-opioid analgesics. Opioids increase the risk of central sleep apnea (CSA) and sleep-related hypoxemia in a dose-dependent fashion. Consider decreasing the opioid dosage in persons with CSA. Respiratory depression, if left untreated, may cause respiratory arrest and death. Carbon dioxide retention from respiratory depression may also worsen opioid sedating effects. Careful monitoring and dose titration is required, particularly when CYP3A4 and/or CYP2D6 inhibitors or inducers are used concomitantly; concurrent use of a CYP3A4 inhibitor or discontinuation of a concurrently used CYP3A4 inducer may increase plasma codeine concentrations with subsequent greater metabolism by CYP2D6, resulting in greater morphine concentrations that may potentiate the risk of fatal respiratory depression or discontinuation of a concomitantly used CYP2D6 inhibitor may decrease plasma codeine concentrations and increase morphine concentrations that may increase the risk for respiratory depression. Management of respiratory depression may include observation, necessary supportive measures, and opioid antagonist use when indicated.

Labor, neonatal opioid withdrawal syndrome, obstetric delivery, pregnancy

Avoid aspirin use during the third trimester of pregnancy (starting at 30 weeks of gestation) due to the risk of premature closure of the fetal ductus arteriosus and persistent pulmonary hypertension in the neonate. If NSAID treatment is deemed necessary between 20 to 30 weeks of pregnancy, limit use to the lowest effective dose and shortest duration possible. Consider ultrasound monitoring of amniotic fluid if NSAID treatment extends beyond 48 hours. Discontinue the NSAID if oligohydramnios occurs and follow up according to clinical practice. These recommendations do not apply to low-dose 81 mg aspirin prescribed for certain conditions in pregnancy. Use of NSAIDs around 20 weeks gestation or later in pregnancy may cause fetal renal dysfunction leading to oligohydramnios, and in some cases, neonatal renal impairment. These adverse outcomes are seen, on average, after days to weeks of treatment, although oligohydramnios has been infrequently reported as soon as 48 hours after NSAID initiation. Oligohydramnios is often, but not always, reversible with treatment discontinuation. Complications of prolonged oligohydramnios may include limb contractures and delayed lung maturation. In some postmarketing cases of impaired neonatal renal function, invasive procedures such as exchange transfusion or dialysis were required. Salicylates have also been associated with alterations in maternal and neonatal hemostasis mechanisms, decreased birth weight, and perinatal mortality. Avoid aspirin 1 week prior to and during labor and obstetric delivery because it can result in excessive blood loss at delivery. Prolonged gestation and labor due to prostaglandin inhibition have been reported. Data over many decades of carisoprodol use in pregnancy have not identified a drug-associated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes. Data on meprobamate, the primary metabolite of carisoprodol, also do not show a consistent association between maternal use of meprobamate and an increased risk of major birth defects. Codeine is not recommended for use during and immediately before labor when other analgesic techniques are more appropriate. Opioids can prolong labor and obstetric delivery by temporarily reducing the strength, duration, and frequency of uterine contractions. This effect is not consistent and may be offset by an increased rate of cervical dilatation, which may shorten labor. Opioids cross the placenta and may produce respiratory depression and psycho-physiologic effects in the neonate. An opioid antagonist (e.g., naloxone) should be available for reversal of opioid-induced respiratory depression in the neonate. Further, prolonged maternal use of opioids during pregnancy may result in neonatal opioid withdrawal syndrome (NOWS). Monitor the exposed neonate for withdrawal symptoms, including irritability, hyperactivity and abnormal sleep pattern, high-pitched cry, tremor, vomiting, diarrhea, and failure to gain weight, and manage accordingly. Onset, duration, and severity of opioid withdrawal may vary based on the specific opioid used, duration of use, timing and amount of last maternal use, and rate of elimination by the newborn. [55881] Guidelines recommend early universal screening of pregnant patients for opioid use and opioid use disorder at the first prenatal visit. Obtain a thorough history of substance use and review the Prescription Drug Monitoring Program to determine if patients have received prior prescriptions for opioids or other high-risk drugs such as benzodiazepines. Discuss the risks and benefits of opioid use during pregnancy, including the risk of becoming physiologically dependent on opioids, the possibility for NOWS, and how long-term opioid use may affect care during a future pregnancy.[64838] [64909] In women undergoing uncomplicated normal spontaneous vaginal birth, consider opioid therapy only if expected benefits for both pain and function are anticipated to outweigh risks to the patient. If opioids are used, use in combination with nonpharmacologic therapy and nonopioid pharmacologic therapy, as appropriate. Use immediate-release opioids instead of extended-release or long-acting opioids; order the lowest effective dosage and prescribe no greater quantity of opioids than needed for the expected duration of such pain severe enough to require opioids.[64909] For women using opioids for chronic pain, consider strategies to avoid or minimize the use of opioids, including alternative pain therapies (i.e., nonpharmacologic) and nonopioid pharmacologic treatments. Opioid agonist pharmacotherapy (e.g., methadone or buprenorphine) is preferable to medically supervised withdrawal in pregnant women with opioid use disorder.[64838]

Adenoidectomy, children, infants, influenza, neonates, neuromuscular disease, obesity, respiratory infection, Reye's syndrome, tonsillectomy, varicella, viral infection

Aspirin; carisoprodol; codeine is contraindicated in neonates, infants, and children younger than 12 years and for postoperative pain management in pediatric patients younger than 18 years after a tonsillectomy and/or adenoidectomy. The American Academy of Pediatrics (AAP) recommends against the use of codeine in all pediatric persons for any indication. Avoid use in persons 12 to 18 years of age who have other risk factors for respiratory depression unless the benefits outweigh the risks. Risk factors include conditions associated with hypoventilation such as postoperative status, obstructive sleep apnea, obesity, respiratory infection, asthma, severe pulmonary disease, neuromuscular disease, and concomitant use of other respiratory depressants. When prescribing codeine for adolescents, choose the lowest effective dose for the shortest period of time and inform patients and caregivers of the risks and the signs of opioid overdose. Codeine metabolism is highly variable and unpredictable, particularly in children younger than 12 years; therapeutic response to recommended doses can range from lack of effect in poor metabolizers to fatality in ultrarapid metabolizers. Ultrarapid metabolizers are more likely to convert codeine to morphine quickly, leading to excessive morphine blood concentrations that can result in fatal respiratory depression. Because some children who are normal metabolizers can convert codeine to morphine at rates similar to ultra-metabolizers, this concern extends to all pediatric patients. Aspirin; carisoprodol; codeine is contraindicated in Reye's syndrome. Do not use aspirin in children for viral infection, with or without fever, because of the risk of Reye's syndrome. Do not use aspirin in children recovering from varicella infection or influenza.

Soma Compound with Codeine

Rx, schedule III

Combination of a salicylate, central-acting muscle relaxant, and opiate agonist
Used for pain and muscle spasm relief and limited mobility associated with musculoskeletal conditions
Risk of dependence/abuse; limit therapy to 2 to 3 weeks; use in patients younger than 12 years is contraindicated

For the treatment of acute, musculoskeletal pain where treatment with an opioid is appropriate and for which alternative treatments are inadequate. Oral dosage (carisoprodol 200 mg, aspirin 325 mg, and codeine 16 mg per tablet) Adults

200 to 400 mg carisoprodol/325 to 650 mg aspirin/16 to 32 mg codeine (1 or 2 tablets) PO 4 times daily. Max: 1,600 mg carisoprodol/2,600 mg aspirin/128 mg codeine (8 tablets)/day. Treatment is generally limited to 2 to 3 weeks.

Hepatic Impairment

Start persons with hepatic disease with a lower than normal dosage of aspirin; carisoprodol; codeine or with longer dosing intervals and titrate slowly while monitoring for signs of respiratory depression, sedation, and hypotension.

Renal Impairment

Avoid aspirin in persons with severe renal failure (i.e., glomerular filtration rate less than 10 mL/minute). Start persons with renal failure with a lower than normal dosage of aspirin; carisoprodol; codeine or with longer dosing intervals and titrate slowly while monitoring for signs of respiratory depression, sedation, and hypotension.

Abciximab: (Moderate) Unless contraindicated, aspirin is used in combination with abciximab. However, both drugs are associated with bleeding. Monitor for bleeding during concomitant therapy.
Abiraterone: (Moderate) Concomitant use of codeine with abiraterone may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of abiraterone could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If abiraterone is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Abiraterone is a moderate inhibitor of CYP2D6.
Abrocitinib: (Contraindicated) Concurrent use with daily aspirin doses higher than 81 mg is contraindicated during the first 3 months of abrocitinib therapy due to an increased risk of bleeding with thrombocytopenia.
Acetaminophen; Aspirin, ASA; Caffeine: (Minor) Caffeine has been reported to increase the metabolism of aspirin.
Acetaminophen; Aspirin; Diphenhydramine: (Major) Reserve concomitant use of opioids and diphenhydramine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant.
Acetaminophen; Caffeine: (Minor) Caffeine has been reported to increase the metabolism of aspirin.
Acetaminophen; Caffeine; Dihydrocodeine: (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking carisoprodol. (Minor) Caffeine has been reported to increase the metabolism of aspirin.
Acetaminophen; Caffeine; Pyrilamine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with pyrilamine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with pyrilamine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. (Minor) Caffeine has been reported to increase the metabolism of aspirin.
Acetaminophen; Chlorpheniramine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with chlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with chlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Acetaminophen; Chlorpheniramine; Dextromethorphan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with chlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with chlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with chlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with chlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with chlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with chlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Acetaminophen; Chlorpheniramine; Phenylephrine : (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with chlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with chlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Acetaminophen; Dextromethorphan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Acetaminophen; Dextromethorphan; Doxylamine: (Major) Reserve concomitant use of opioids and doxylamine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant.
Acetaminophen; Dextromethorphan; Guaifenesin; Phenylephrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Acetaminophen; Dextromethorphan; Guaifenesin; Pseudoephedrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Acetaminophen; Dextromethorphan; Phenylephrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Acetaminophen; Dextromethorphan; Pseudoephedrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Acetaminophen; Dichloralphenazone; Isometheptene: (Moderate) Additive CNS depression is possible if skeletal muscle relaxants are used concomitantly with other CNS depressants. Dosage adjustments of one or both medications may be necessary.
Acetaminophen; Diphenhydramine: (Major) Reserve concomitant use of opioids and diphenhydramine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant.
Acetaminophen; Hydrocodone: (Major) Concomitant use of hydrocodone with other CNS depressants may lead to hypotension, profound sedation, coma, respiratory depression and death. Prior to concurrent use of hydrocodone in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. Hydrocodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate hydrocodone at 20 to 30% of the usual dosage in patients that are concurrently receiving another CNS depressant. Also consider a using a lower dose of the CNS depressant. Monitor patients for sedation and respiratory depression. (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking carisoprodol.
Acetaminophen; Ibuprofen: (Major) Concomitant use of analgesic doses of aspirin and ibuprofen is generally not recommended due to the increased risk of bleeding and renal impairment. Because there may be an increased risk of cardiovascular events due to the interference of ibuprofen with the antiplatelet effect of aspirin, for patients taking low-dose aspirin for cardioprotection who require analgesics, consider use of an NSAID that does not interfere with the antiplatelet effect of aspirin, or non-NSAID analgesics, as appropriate. Administer single doses of ibuprofen at least 2 to 4 hours or more after aspirin and wait 8 hours after ibuprofen administration before administering aspirin to avoid significant interference. Monitor for signs and symptoms of renal impairment. Pharmacodynamic studies have demonstrated interference with the antiplatelet activity of aspirin when ibuprofen 400 mg 3 times daily is administered with enteric-coated low-dose aspirin. The interaction exists even after ibuprofen 400 mg once daily, particularly when ibuprofen is dosed prior to aspirin. The interaction is alleviated if immediate-release low-dose aspirin is dosed at least 2 hours prior to a once daily regimen of ibuprofen; however, this finding cannot be extended to enteric-coated low-dose aspirin. A decrease in antiplatelet activity (53%) was observed when ibuprofen 400 mg once daily was administered 2 hours before low-dose immediate-release aspirin 81 mg/day for 6 days. An interaction was still observed, but minimized, when ibuprofen 400 mg once daily was administered as early as 8 hours before immediate-release aspirin (90.7%). There was no interaction with the antiplatelet activity of aspirin when ibuprofen 400 mg once daily was administered 2 hours after immediate-release aspirin (99.2%). In another study of low-dose immediate-release aspirin 81 mg/day and ibuprofen 400 mg 3 times daily (1, 7, and 13 hours post-aspirin dose) for 10 consecutive days, there was no interaction with the antiplatelet activity of aspirin (98.3%); however, there were individuals with aspirin antiplatelet activity below 95%, with the lowest being 90.2%. When a similarly designed study was conducted with enteric-coated aspirin 81 mg/day for 6 days and ibuprofen 400 mg 3 times daily (2, 7 and 12 h post-aspirin dose) for 6 days, there was an interaction with the antiplatelet activity at 24 hours after the day 6 aspirin dose (67%). Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone. Ibuprofen is not a substitute for low dose aspirin for cardiovascular protection.
Acetaminophen; Oxycodone: (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Reduce the initial oxycodone dosage by one-third to one-half when using the extended-release tablets. (Major) Concomitant use of oxycodone with other opiate agonists may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Prior to concurrent use of oxycodone in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. If a CNS depressant is used concurrently with oxycodone, a reduced dosage of oxycodone and/or the CNS depressant is recommended; use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor for sedation and respiratory depression.
Acetaminophen; Pamabrom; Pyrilamine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with pyrilamine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with pyrilamine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Acetazolamide: (Major) Avoid the coadministration of high-dose salicylates and carbonic anhydrase inhibitors whenever possible. There were reports of anorexia, tachypnea, lethargy, metabolic acidosis, coma, and death with high-dose aspirin and acetazolamide. Two mechanisms could cause increased acetazolamide concentrations, resulting in CNS depression and metabolic acidosis: first, competition with aspirin for renal tubular secretion and, second, displacement by salicylates from plasma protein binding sites. Additionally, carbonic anhydrase inhibitors alkalinize urine and increase the excretion of normal doses of salicylates; decreased plasma salicylate concentrations may or may not be clinically significant.
Acidifying Agents: (Moderate) Acidification of the urine may increase serum concentrations of salicylates by increasing tubular reabsorption of salicylates, however, this interaction is not likely to be clinically significant since the urine is normally acidic.
Acrivastine; Pseudoephedrine: (Major) Avoid coadministration of opioid agonists with acrivastine due to the risk of additive CNS depression. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant.
Adagrasib: (Moderate) Concomitant use of codeine with adagrasib may alter codeine plasma concentrations, resulting in an unpredictable effect such as reduced efficacy or symptoms of opioid withdrawal or prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage adjustment of codeine until stable drug effects are achieved. Discontinuation of adagrasib could alter codeine plasma concentrations, resulting in an unpredictable effect such as prolonged opioid adverse reactions or decreased opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If adagrasib is discontinued, monitor the patient carefully and consider adjusting the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Adagrasib is a dual moderate CYP2D6 and strong CYP3A inhibitor. CYP3A inhibitors may increase codeine-related adverse effects while CYP2D6 inhibitors may reduce efficacy.
Ado-Trastuzumab emtansine: (Moderate) Use caution if coadministration of aspirin with ado-trastuzumab emtansine is necessary due to reports of severe and sometimes fatal hemorrhage, including intracranial bleeding, with ado-trastuzumab emtansine therapy. Consider additional monitoring when concomitant use is medically necessary. While some patients who experienced bleeding during ado-trastuzumab therapy were also receiving anticoagulation therapy, others had no known additional risk factors.
Aldesleukin, IL-2: (Moderate) Aldesleukin, IL-2 may affect CNS function significantly. Therefore, psychotropic pharmacodynamic interactions could occur following concomitant administration of drugs with significant CNS or psychotropic activity such as opiate agonists. In addition, aldesleukin, IL-2, is a CYP3A4 inhibitor and may increase oxycodone plasma concentrations and related toxicities including potentially fatal respiratory depression. If therapy with both agents is necessary, monitor patients for an extended period and adjust oxycodone dosage as necessary.
Alendronate: (Minor) Monitor for gastrointestinal adverse events during concurrent use of alendronate and aspirin. Both medications have been associated with gastrointestinal irritation although data suggest concomitant use introduces little additional risk for adverse effects for most patients.
Alendronate; Cholecalciferol: (Minor) Monitor for gastrointestinal adverse events during concurrent use of alendronate and aspirin. Both medications have been associated with gastrointestinal irritation although data suggest concomitant use introduces little additional risk for adverse effects for most patients.
Alfentanil: (Major) Concomitant use of alfentanil with carisoprodol may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation.
Aliskiren; Hydrochlorothiazide, HCTZ: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Alkalinizing Agents: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid.
Almotriptan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor agonists. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Alogliptin: (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
Alogliptin; Metformin: (Moderate) Monitor blood glucose during concomitant metformin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
Alogliptin; Pioglitazone: (Moderate) Monitor blood glucose during concomitant thiazolidinedione and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood glucose concentrations. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
Alosetron: (Major) Patients taking medications that decrease GI motility may be at greater risk for serious complications from alosetron, like constipation, via a pharmacodynamic interaction. Constipation is the most frequently reported adverse effect with alosetron. Alosetron, if used with drugs such as opiate agonists, may seriously worsen constipation, leading to events such as GI obstruction/impaction or paralytic ileus.
Alpha-glucosidase Inhibitors: (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
Alprazolam: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Moderate) Concomitant use of skeletal muscle relaxants with benzodiazepines can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take benzodiazepines with another CNS depressant for symptoms of excess sedation.
Alvimopan: (Moderate) Patients should not take alvimopan if they have received therapeutic doses of opiate agonists for more than seven consecutive days immediately before initiation of alvimopan therapy. Patients recently exposed to opioids are expected to be more sensitive to the effects of mu-opioid receptor antagonists and may experience adverse effects localized to the gastrointestinal tract such as abdominal pain, nausea, vomiting, and diarrhea.
Amide local anesthetics: (Moderate) The use of these drugs together must be approached with caution. Although commonly used together for additive analgesic effects, the patient must be monitored for respiratory depression, hypotension, and excessive sedation due to additive effects on the CNS and blood pressure. In rare instances, serious morbidity and mortality has occurred. Limit the use of opiate pain medications with local anesthetics to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. The use of the local anesthetic may allow for the use a lower initial dose of the opiate and then the doses can be titrated to proper clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
Amiloride: (Moderate) Monitor for decreased diuretic efficacy and additive orthostatic hypotension when amiloride is administered with codeine. Adjustments to diuretic therapy may be needed in some patients. The efficacy of diuretics may be reduced due to opioid-induced release of antidiuretic hormone. (Moderate) Salicylates can increase the risk of renal insufficiency in patients receiving diuretics, secondary to effects on renal blood flow. Salicylates inhibit renal prostaglandin production, which causes salt and water retention and decreased renal blood flow. Coadministration may cause hyperkalemia.
Amiloride; Hydrochlorothiazide, HCTZ: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for decreased diuretic efficacy and additive orthostatic hypotension when amiloride is administered with codeine. Adjustments to diuretic therapy may be needed in some patients. The efficacy of diuretics may be reduced due to opioid-induced release of antidiuretic hormone. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic. (Moderate) Salicylates can increase the risk of renal insufficiency in patients receiving diuretics, secondary to effects on renal blood flow. Salicylates inhibit renal prostaglandin production, which causes salt and water retention and decreased renal blood flow. Coadministration may cause hyperkalemia.
Aminoglycosides: (Minor) Due to the inhibition of renal prostaglandins by salicylates, concurrent use of salicylates and other nephrotoxic agents like the aminoglycosides may lead to additive nephrotoxicity.
Amiodarone: (Moderate) Concomitant use of codeine with amiodarone may alter codeine plasma concentrations, resulting in an unpredictable effect such as reduced efficacy or symptoms of opioid withdrawal or prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage adjustment of codeine until stable drug effects are achieved. Discontinuation of amiodarone could alter codeine plasma concentrations, resulting in an unpredictable effect such as prolonged opioid adverse reactions or decreased opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If amiodarone is discontinued, monitor the patient carefully and consider adjusting the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Amiodarone is a moderate inhibitor of CYP3A4 and CYP2D6. CYP3A4 inhibitors may increase codeine-related adverse effects while CYP2D6 inhibitors may reduce efficacy.
Amitriptyline: (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Moderate) Concomitant use of carisoprodol with tricyclic antidepressants can result in additive CNS depression (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Amlodipine: (Moderate) Monitor for an increase in codeine-related adverse reactions including sedation and respiratory depression if coadministration with amlodipine is necessary; adjust the dose of codeine if necessary. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Amlodipine is a weak CYP3A4 inhibitor. Concomitant use may result in an increase in codeine plasma concentrations, resulting in greater metabolism by CYP2D6 and increased morphine concentrations.
Amlodipine; Atorvastatin: (Moderate) Monitor for an increase in codeine-related adverse reactions including sedation and respiratory depression if coadministration with amlodipine is necessary; adjust the dose of codeine if necessary. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Amlodipine is a weak CYP3A4 inhibitor. Concomitant use may result in an increase in codeine plasma concentrations, resulting in greater metabolism by CYP2D6 and increased morphine concentrations.
Amlodipine; Benazepril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Moderate) Monitor for an increase in codeine-related adverse reactions including sedation and respiratory depression if coadministration with amlodipine is necessary; adjust the dose of codeine if necessary. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Amlodipine is a weak CYP3A4 inhibitor. Concomitant use may result in an increase in codeine plasma concentrations, resulting in greater metabolism by CYP2D6 and increased morphine concentrations.
Amlodipine; Celecoxib: (Major) Concomitant use of analgesic doses of aspirin and celecoxib is generally not recommended due to the increased risk of bleeding. Concurrent use of analgesic doses of aspirin with NSAIDs does not produce a greater therapeutic effect compared to the use of NSAIDs alone. Celecoxib (200 to 400 mg/day) did not interfere with the cardioprotective antiplatelet effect of aspirin (100 to 325 mg) in 2 studies in healthy volunteers and in patients with osteoarthritis and established heart disease. Celecoxib is not a substitute for low dose aspirin for cardiovascular protection. (Moderate) Concomitant use of codeine with celecoxib may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of celecoxib could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If celecoxib is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Celecoxib is an inhibitor of CYP2D6. (Moderate) Monitor for an increase in codeine-related adverse reactions including sedation and respiratory depression if coadministration with amlodipine is necessary; adjust the dose of codeine if necessary. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Amlodipine is a weak CYP3A4 inhibitor. Concomitant use may result in an increase in codeine plasma concentrations, resulting in greater metabolism by CYP2D6 and increased morphine concentrations.
Amlodipine; Olmesartan: (Moderate) Monitor for an increase in codeine-related adverse reactions including sedation and respiratory depression if coadministration with amlodipine is necessary; adjust the dose of codeine if necessary. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Amlodipine is a weak CYP3A4 inhibitor. Concomitant use may result in an increase in codeine plasma concentrations, resulting in greater metabolism by CYP2D6 and increased morphine concentrations.
Amlodipine; Valsartan: (Moderate) Monitor for an increase in codeine-related adverse reactions including sedation and respiratory depression if coadministration with amlodipine is necessary; adjust the dose of codeine if necessary. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Amlodipine is a weak CYP3A4 inhibitor. Concomitant use may result in an increase in codeine plasma concentrations, resulting in greater metabolism by CYP2D6 and increased morphine concentrations.
Amlodipine; Valsartan; Hydrochlorothiazide, HCTZ: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for an increase in codeine-related adverse reactions including sedation and respiratory depression if coadministration with amlodipine is necessary; adjust the dose of codeine if necessary. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Amlodipine is a weak CYP3A4 inhibitor. Concomitant use may result in an increase in codeine plasma concentrations, resulting in greater metabolism by CYP2D6 and increased morphine concentrations. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Amobarbital: (Major) Concomitant use of codeine with barbiturates may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with barbiturates to only patients for whom alternative treatment options are inadequate. It is recommended to avoid this combination when codeine is being used for cough. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Additionally, concomitant use of codeine with a barbiturate can decrease codeine concentrations, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. Monitor for reduced efficacy of codeine and signs of opioid withdrawal. Discontinuation of a barbiturate may increase the risk of opioid-related adverse reactions, such as fatal respiratory depression. Barbiturates induce CYP3A4. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. (Moderate) Concomitant use of skeletal muscle relaxants with barbiturates can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take barbiturates with another CNS depressant for symptoms of excess sedation.
Amoxapine: (Major) Concomitant use of opioid agonists with amoxapine may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking amoxapine. Limit the use of opioid pain medications with amoxapine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. (Moderate) Skeletal muscle relaxants should be combined cautiously with cyclic antidepressants like maprotiline because they could cause additive CNS depressant effects. Depending on the specific agent (e.g., cyclobenzaprine, and orphenadrine), additive anticholinergic effects may also be seen. Clinicians should note that antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Patients should be monitored for excessive adverse effects from either agent.
Amoxicillin: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Amoxicillin; Clarithromycin; Omeprazole: (Moderate) Concomitant use of codeine with clarithromycin may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of clarithromycin could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If clarithromycin is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Clarithromycin is a strong inhibitor of CYP3A4. (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as omeprazole, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects. (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Amoxicillin; Clavulanic Acid: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Amphetamine: (Moderate) If concomitant use of codeine and amphetamines is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Amphetamine; Dextroamphetamine: (Moderate) If concomitant use of codeine and amphetamines is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Amphetamines: (Moderate) If concomitant use of codeine and amphetamines is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Amphotericin B lipid complex (ABLC): (Minor) Concurrent use of amphotericin B and other potentially nephrotoxic medications, like the salicylates, may enhance the potential for drug-induced renal toxicity.
Amphotericin B liposomal (LAmB): (Minor) Concurrent use of amphotericin B and other potentially nephrotoxic medications, like the salicylates, may enhance the potential for drug-induced renal toxicity.
Amphotericin B: (Minor) Concurrent use of amphotericin B and other potentially nephrotoxic medications, like the salicylates, may enhance the potential for drug-induced renal toxicity.
Ampicillin: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Ampicillin; Sulbactam: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Anagrelide: (Moderate) Use caution with the coadministration of aspirin and anagrelide. The coadministration of single or repeated doses of anagrelide and aspirin resulted in greater ex vivo anti-platelet aggregation effects than administration of aspirin alone. In an observational study, the concomitant use of anagrelide and aspirin increased the rate of major hemorrhagic events compared to patients receiving other cytoreductive therapy. Assess the risks and benefits of concomitant aspirin and anagrelide use, particularly in patients at high risk for hemorrhage. Monitor for bleeding during concomitant therapy.
Angiotensin-converting enzyme inhibitors: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
Antithrombin III: (Moderate) Large doses of salicylates (more than 3 to 4 g/day) can cause hypoprothrombinemia, an additional risk factor for bleeding. Patients taking large doses of salicylates and antithrombin III should be monitored closely for bleeding.
Apalutamide: (Moderate) Concomitant use of codeine with apalutamide can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If apalutamide is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Apalutamide is a strong CYP3A4 inducer. (Moderate) Monitor for an altered clinical response to carisoprodol if coadministration with apalutamide is necessary. Carisoprodol is metabolized by CYP2C19 to form meprobamate. Apalutamide is a strong CYP2C19 inducer. Coadministration could decrease exposure to carisoprodol and increase exposure to meprobamate. The full pharmacological impact of these potential alterations of exposures in terms of either efficacy or safety of carisoprodol is unknown.
Apixaban: (Major) Large doses of salicylates (3 to 4 g/day or more) can cause hypoprothrombinemia, an additional risk factor for bleeding. Patients taking large doses of salicylates and apixaban should be monitored closely for bleeding.
Apomorphine: (Major) Concomitant use of opioid agonists with apomorphine may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking apomorphine. Limit the use of opioid pain medications with apomorphine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. Dopaminergic agents like apomorphine have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. (Moderate) Apomorphine causes significant somnolence. Concomitant administration of apomorphine and CNS depressants could result in additive depressant effects.
Apraclonidine: (Minor) Theoretically, apraclonidine might potentiate the effects of CNS depressant drugs such as opiate agonists. Although no specific drug interactions were identified with systemic agents and apraclonidine during clinical trials, apraclonidine can cause dizziness and somnolence.
Aprepitant, Fosaprepitant: (Moderate) Concomitant use of codeine with oral, multi-day regimens of aprepitant, fosaprepitant may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of aprepitant, fosaprepitant could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If aprepitant, fosaprepitant is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Aprepitant, fosaprepitant, when administered as an oral, 3-day regimen, is a moderate inhibitor of CYP3A4.
Aripiprazole: (Moderate) Concomitant use of opioid agonists with aripiprazole may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking aripiprazole. Limit the use of opioid pain medications with aripiprazole to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression.
Artemether; Lumefantrine: (Moderate) Concomitant use of codeine with lumefantrine may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of lumefantrine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If lumefantrine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Lumefantrine is a moderate inhibitor of CYP2D6.
Articaine; Epinephrine: (Moderate) The use of these drugs together must be approached with caution. Although commonly used together for additive analgesic effects, the patient must be monitored for respiratory depression, hypotension, and excessive sedation due to additive effects on the CNS and blood pressure. In rare instances, serious morbidity and mortality has occurred. Limit the use of opiate pain medications with local anesthetics to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. The use of the local anesthetic may allow for the use a lower initial dose of the opiate and then the doses can be titrated to proper clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
Asciminib: (Moderate) Concomitant use of codeine with asciminib may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of asciminib could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If asciminib is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Asciminib is a weak inhibitor of CYP3A.
Ascorbic Acid, Vitamin C: (Minor) Agents that acidify the urine should be avoided in patients receiving high-dose salicylates. Urinary pH changes can decrease salicylate excretion. However, if the urine is acidic prior to administration of an acidifying agent, the increase in salicylic acid concentrations should be minimal.
Asenapine: (Moderate) Concomitant use of opioid agonists with asenapine may cause excessive sedation

and somnolence. Avoid prescribing opioid cough medications in patients taking asenapine. Limit the use of opioid pain medications with asenapine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression.
Aspirin, ASA; Butalbital; Caffeine: (Major) Concomitant use of codeine with barbiturates may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with barbiturates to only patients for whom alternative treatment options are inadequate. It is recommended to avoid this combination when codeine is being used for cough. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Additionally, concomitant use of codeine with a barbiturate can decrease codeine concentrations, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. Monitor for reduced efficacy of codeine and signs of opioid withdrawal. Discontinuation of a barbiturate may increase the risk of opioid-related adverse reactions, such as fatal respiratory depression. Barbiturates induce CYP3A4. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. (Moderate) Concomitant use of skeletal muscle relaxants with barbiturates can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take barbiturates with another CNS depressant for symptoms of excess sedation. (Minor) Caffeine has been reported to increase the metabolism of aspirin.
Aspirin, ASA; Caffeine: (Minor) Caffeine has been reported to increase the metabolism of aspirin.
Aspirin, ASA; Caffeine; Orphenadrine: (Major) Concomitant use of opioid agonists with orphenadrine may cause excessive sedation and somnolence. Limit the use of opioid pain medications with orphenadrine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking orphenadrine. (Minor) Caffeine has been reported to increase the metabolism of aspirin.
Aspirin, ASA; Carisoprodol: (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking carisoprodol.
Aspirin, ASA; Citric Acid; Sodium Bicarbonate: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid.
Aspirin, ASA; Dipyridamole: (Moderate) Although aspirin may be used in combination with dipyridamole, both drugs are associated with bleeding. Monitor for bleeding during concomitant therapy.
Aspirin, ASA; Omeprazole: (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as omeprazole, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
Aspirin, ASA; Oxycodone: (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Reduce the initial oxycodone dosage by one-third to one-half when using the extended-release tablets. (Major) Concomitant use of oxycodone with other opiate agonists may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Prior to concurrent use of oxycodone in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. If a CNS depressant is used concurrently with oxycodone, a reduced dosage of oxycodone and/or the CNS depressant is recommended; use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor for sedation and respiratory depression.
Atazanavir: (Moderate) Concomitant use of codeine with atazanavir may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of atazanavir could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If atazanavir is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Atazanavir is a strong inhibitor of CYP3A4.
Atazanavir; Cobicistat: (Moderate) Concomitant use of codeine with atazanavir may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of atazanavir could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If atazanavir is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Atazanavir is a strong inhibitor of CYP3A4. (Moderate) Concomitant use of codeine with cobicistat may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of cobicistat could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If cobicistat is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Cobicistat is a strong inhibitor of CYP3A4.
Atenolol; Chlorthalidone: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Atropine: (Major) Reserve concomitant use of codeine and atropine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus.
Atropine; Difenoxin: (Major) Reserve concomitant use of codeine and atropine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Concurrent administration of diphenoxylate/difenoxin with carisoprodol can potentiate the CNS-depressant effects of diphenoxylate/difenoxin. Use caution during coadministration. (Moderate) Concurrent administration of diphenoxylate/difenoxin with other opiate agonists can potentiate the CNS-depressant effects of diphenoxylate/difenoxin. Use caution during coadministration. In addition, diphenoxylate/difenoxin use may cause constipation; cases of severe GI reactions including toxic megacolon and adynamic ileus have been reported. Reduced GI motility when combined with opiate agonists may increase the risk of serious GI related adverse events.
Avacopan: (Moderate) Concomitant use of codeine with avacopan may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of avacopan could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If avacopan is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Avacopan is a weak inhibitor of CYP3A.
Azelastine: (Major) Concomitant use of opioid agonists with azelastine may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking azelastine. Limit the use of opioid pain medications with azelastine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. (Moderate) Monitor for excessive sedation and somnolence during coadministration of azelastine and skeletal muscle relaxants. Concurrent use may result in additive CNS depression.
Azelastine; Fluticasone: (Major) Concomitant use of opioid agonists with azelastine may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking azelastine. Limit the use of opioid pain medications with azelastine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. (Moderate) Monitor for excessive sedation and somnolence during coadministration of azelastine and skeletal muscle relaxants. Concurrent use may result in additive CNS depression.
Azilsartan; Chlorthalidone: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Bacitracin: (Minor) Additive nephrotoxicity may occur with concurrent use of systemic bacitracin and other nephrotoxic agents, including salicylates. Topical administration of any preparation containing bacitracin, especially when applied to large surface areas, also should not be given with other drugs that have a nephrotoxic potential.
Baclofen: (Major) Concomitant use of opioid agonists with baclofen may cause excessive sedation and somnolence. Limit the use of opioid pain medications with baclofen to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking baclofen.
Barbiturates: (Major) Concomitant use of codeine with barbiturates may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with barbiturates to only patients for whom alternative treatment options are inadequate. It is recommended to avoid this combination when codeine is being used for cough. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Additionally, concomitant use of codeine with a barbiturate can decrease codeine concentrations, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. Monitor for reduced efficacy of codeine and signs of opioid withdrawal. Discontinuation of a barbiturate may increase the risk of opioid-related adverse reactions, such as fatal respiratory depression. Barbiturates induce CYP3A4. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. (Moderate) Concomitant use of skeletal muscle relaxants with barbiturates can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take barbiturates with another CNS depressant for symptoms of excess sedation. (Moderate) Due to high protein binding, salicylates could be displaced from binding sites, or could displace other highly protein-bound drugs such as barbiturates. An enhanced effect of the displaced drug may occur.
Belladonna; Opium: (Major) Concomitant use of opoid agonists with carisoprodol may cause respiratory depression, profound sedation, and death. Limit the use of opioid agonists with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Consider prescribing naloxone for emergency treatment of opioid overdose. (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and belladonna use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Belumosudil: (Moderate) Concomitant use of codeine with belumosudil may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of belumosudil could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If belumosudil is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Belumosudil is a weak inhibitor of CYP3A.
Belzutifan: (Moderate) Monitor for reduced efficacy of codeine and signs of opioid withdrawal in patients who have developed physical dependence if coadministration with belzutifan is necessary; consider increasing the dose of codeine as needed. It is recommended to avoid this combination when codeine is being used for cough. If belzutifan is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Belzutifan is a weak CYP3A inducer. Concomitant use with belzutifan can increase norcodeine levels via increased CYP3A metabolism, resulting in decreased metabolism via CYP2D6 resulting in lower morphine levels; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence.
Benazepril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
Benazepril; Hydrochlorothiazide, HCTZ: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Benzhydrocodone; Acetaminophen: (Major) Concomitant use of benzhydrocodone with carisoprodol may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. (Major) Concomitant use of opioid agonists with benzhydrocodone may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of benzhydrocodone with opioid agonists to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If benzhydrocodone is initiated in a patient taking codeine, reduce initial dosage and titrate to clinical response. If codeine is prescribed in a patient taking benzhydrocodone, use a lower initial dose of codeine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opioid cough medications in patients taking other opioid agonists. Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of benzhydrocodone and codeine because of the potential risk of serotonin syndrome. Discontinue benzhydrocodone if serotonin syndrome is suspected. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Benzodiazepines: (Moderate) Concomitant use of skeletal muscle relaxants with benzodiazepines can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take benzodiazepines with another CNS depressant for symptoms of excess sedation.
Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Contraindicated) Codeine use in patients taking methylene blue or within 14 days of stopping such treatment is contraindicated due to the risk of serotonin syndrome or opioid toxicity. If urgent use of an opioid is necessary, use test doses and frequent titration of small doses of another opioid to treat pain while closely monitoring blood pressure and signs and symptoms of CNS and respiratory depression. (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and hyoscyamine use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Benzphetamine: (Moderate) If concomitant use of codeine and amphetamines is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Benztropine: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and benztropine use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Berotralstat: (Moderate) Concomitant use of codeine with berotralstat may alter codeine plasma concentrations, resulting in an unpredictable effect such as reduced efficacy or symptoms of opioid withdrawal or prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage adjustment of codeine until stable drug effects are achieved. Discontinuation of berotralstat could alter codeine plasma concentrations, resulting in an unpredictable effect such as prolonged opioid adverse reactions or decreased opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If berotralstat is discontinued, monitor the patient carefully and consider adjusting the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Berotralstat is a moderate inhibitor of CYP3A4 and CYP2D6. CYP3A4 inhibitors may increase codeine-related adverse effects while CYP2D6 inhibitors may reduce efficacy.
Beta-blockers: (Moderate) Concurrent use of beta-blockers with aspirin and other salicylates may result in loss of antihypertensive activity due to inhibition of renal prostaglandins and thus, salt and water retention and decreased renal blood flow.
Bethanechol: (Moderate) Bethanechol facilitates intestinal and bladder function via parasympathomimetic actions. Opiate agonists impair the peristaltic activity of the intestine. Thus, these drugs can antagonize the beneficial actions of bethanechol on GI motility.
Betrixaban: (Major) Monitor patients closely and promptly evaluate any signs or symptoms of bleeding if betrixaban and aspirin are used concomitantly. Coadministration of betrixaban and aspirin may increase the risk of bleeding.
Bexarotene: (Moderate) Concomitant use of codeine with bexarotene can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If bexarotene is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Bexarotene is a moderate CYP3A4 inducer.
Bismuth Subcitrate Potassium; Metronidazole; Tetracycline: (Moderate) Additive constipation may be seen with concurrent use of opiate agonists and antidiarrheals. Opioids increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect.
Bismuth Subsalicylate: (Moderate) Additive constipation may be seen with concurrent use of opiate agonists and antidiarrheals. Opioids increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect. (Moderate) Monitor for salicylate-related adverse effects, including salicylate toxicity, if concomitant use of aspirin and bismuth subsalicylate is necessary. Adverse reactions, such as bleeding, renal impairment, and tinnitus, may occur.
Bismuth Subsalicylate; Metronidazole; Tetracycline: (Moderate) Additive constipation may be seen with concurrent use of opiate agonists and antidiarrheals. Opioids increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect. (Moderate) Monitor for salicylate-related adverse effects, including salicylate toxicity, if concomitant use of aspirin and bismuth subsalicylate is necessary. Adverse reactions, such as bleeding, renal impairment, and tinnitus, may occur.
Bisoprolol; Hydrochlorothiazide, HCTZ: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Bortezomib: (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as bortezomib, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
Bosentan: (Moderate) Concomitant use of codeine with bosentan can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If bosentan is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Bosentan is a moderate CYP3A4 inducer.
Botulinum Toxins: (Moderate) Excessive neuromuscular weakness may be exacerbated by coadministration of a botulinum toxin with skeletal muscle relaxants. Advise patients to seek medical assistance if they develop any unusual symptoms (including difficulty with swallowing, speaking, or breathing or walking), or if any existing symptom worsens during use of a botulinum toxin.
Brexanolone: (Moderate) Concomitant use of brexanolone with CNS depressants like the opiate agonists may increase the likelihood or severity of adverse reactions related to sedation and additive CNS depression. Monitor for excessive sedation, dizziness, and a potential for loss of consciousness during brexanolone use.
Brexpiprazole: (Major) Concomitant use of opioid agonists with brexpiprazole may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking brexpiprazole. Limit the use of opioid pain medications with brexpiprazole to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression.
Brigatinib: (Moderate) Monitor for reduced efficacy of codeine and signs of opioid withdrawal in patients who have developed physical dependence if coadministration with brigatinib is necessary; consider increasing the dose of codeine as needed. It is recommended to avoid this combination when codeine is being used for cough. If brigatinib is discontinued, consider a dose reduction of codeine, and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Brigatinib is a weak CYP3A4 inducer. Concomitant use with brigatinib can increase norcodeine levels via increased CYP3A4 metabolism, resulting in decreased metabolism via CYP2D6 resulting in lower morphine levels; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence.
Brimonidine: (Moderate) Based on the sedative effects of brimonidine in individual patients, brimonidine administration has potential to enhance the CNS depressants effects of opiate agonists.
Brimonidine; Brinzolamide: (Moderate) Based on the sedative effects of brimonidine in individual patients, brimonidine administration has potential to enhance the CNS depressants effects of opiate agonists.
Brimonidine; Timolol: (Moderate) Based on the sedative effects of brimonidine in individual patients, brimonidine administration has potential to enhance the CNS depressants effects of opiate agonists.
Bromocriptine: (Minor) Bromocriptine is highly bound (more than 90%) to serum proteins. Therefore, it may increase the unbound fraction of other highly protein-bound medications (e.g., aspirin and other salicylates), which may alter their effectiveness and risk for side effects.
Brompheniramine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with brompheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with brompheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Brompheniramine; Dextromethorphan; Phenylephrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with brompheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with brompheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Brompheniramine; Phenylephrine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with brompheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with brompheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Brompheniramine; Pseudoephedrine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with brompheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with brompheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Brompheniramine; Pseudoephedrine; Dextromethorphan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with brompheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with brompheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Budesonide; Glycopyrrolate; Formoterol: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and glycopyrrolate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Bumetanide: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a loop diuretic and codeine; increase the dosage of the loop diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. (Moderate) Salicylates may decrease the diuretic, natriuretic, and antihypertensive actions of diuretics, possibly through inhibition of renal prostaglandin synthesis. Patients receiving loop diuretics and salicylates should be monitored for changes in the effectiveness of their diuretic therapy.
Bupivacaine Liposomal: (Moderate) The use of these drugs together must be approached with caution. Although commonly used together for additive analgesic effects, the patient must be monitored for respiratory depression, hypotension, and excessive sedation due to additive effects on the CNS and blood pressure. In rare instances, serious morbidity and mortality has occurred. Limit the use of opiate pain medications with local anesthetics to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. The use of the local anesthetic may allow for the use a lower initial dose of the opiate and then the doses can be titrated to proper clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
Bupivacaine: (Moderate) The use of these drugs together must be approached with caution. Although commonly used together for additive analgesic effects, the patient must be monitored for respiratory depression, hypotension, and excessive sedation due to additive effects on the CNS and blood pressure. In rare instances, serious morbidity and mortality has occurred. Limit the use of opiate pain medications with local anesthetics to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. The use of the local anesthetic may allow for the use a lower initial dose of the opiate and then the doses can be titrated to proper clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
Bupivacaine; Epinephrine: (Moderate) The use of these drugs together must be approached with caution. Although commonly used together for additive analgesic effects, the patient must be monitored for respiratory depression, hypotension, and excessive sedation due to additive effects on the CNS and blood pressure. In rare instances, serious morbidity and mortality has occurred. Limit the use of opiate pain medications with local anesthetics to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. The use of the local anesthetic may allow for the use a lower initial dose of the opiate and then the doses can be titrated to proper clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
Bupivacaine; Lidocaine: (Moderate) The use of these drugs together must be approached with caution. Although commonly used together for additive analgesic effects, the patient must be monitored for respiratory depression, hypotension, and excessive sedation due to additive effects on the CNS and blood pressure. In rare instances, serious morbidity and mortality has occurred. Limit the use of opiate pain medications with local anesthetics to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. The use of the local anesthetic may allow for the use a lower initial dose of the opiate and then the doses can be titrated to proper clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
Bupivacaine; Meloxicam: (Major) Concomitant use of low dose aspirin or analgesic doses of aspirin and meloxicam is generally not recommended due to the increased risk of bleeding and renal impairment. Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone. Meloxicam is not a substitute for low dose aspirin for cardiovascular protection. (Moderate) The use of these drugs together must be approached with caution. Although commonly used together for additive analgesic effects, the patient must be monitored for respiratory depression, hypotension, and excessive sedation due to additive effects on the CNS and blood pressure. In rare instances, serious morbidity and mortality has occurred. Limit the use of opiate pain medications with local anesthetics to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. The use of the local anesthetic may allow for the use a lower initial dose of the opiate and then the doses can be titrated to proper clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
Buprenorphine: (Major) Avoid concomitant use of codeine and a mixed opioid agonist/antagonist, such as buprenorphine, due to risk for reduced analgesic effect of codeine and/or precipitation of withdrawal symptoms. (Moderate) Concomitant use of buprenorphine with other CNS depressants can lead to additive CNS depressive effects. Hypotension, profound sedation, coma, respiratory depression, or death may occur; examples of other CNS depressants can include skeletal muscle relaxants. Prior to concurrent use of buprenorphine in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. A dose reduction of one or both drugs may be warranted. It is recommended that the injectable buprenorphine dose be halved for patients who receive other drugs with CNS depressant effects; for the buprenorphine transdermal patch, start with the 5 mcg/hour patch. Monitor patients for sedation or respiratory depression.
Buprenorphine; Naloxone: (Major) Avoid concomitant use of codeine and a mixed opioid agonist/antagonist, such as buprenorphine, due to risk for reduced analgesic effect of codeine and/or precipitation of withdrawal symptoms. (Moderate) Concomitant use of buprenorphine with other CNS depressants can lead to additive CNS depressive effects. Hypotension, profound sedation, coma, respiratory depression, or death may occur; examples of other CNS depressants can include skeletal muscle relaxants. Prior to concurrent use of buprenorphine in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. A dose reduction of one or both drugs may be warranted. It is recommended that the injectable buprenorphine dose be halved for patients who receive other drugs with CNS depressant effects; for the buprenorphine transdermal patch, start with the 5 mcg/hour patch. Monitor patients for sedation or respiratory depression.
Bupropion: (Moderate) Concomitant use of codeine with bupropion may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of bupropion could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If bupropion is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Bupropion is a strong inhibitor of CYP2D6.
Bupropion; Naltrexone: (Major) When naltrexone is used as adjuvant treatment of opiate or alcohol dependence, use is contraindicated in patients currently receiving opiate agonists. Naltrexone will antagonize the therapeutic benefits of opiate agonists and will induce a withdrawal reaction in patients with physical dependence to opioids. An opiate antagonist should only be administered to a patient taking codeine with clinically significant respiratory or cardiovascular depression. Also, patients should be opiate-free for at least 7-10 days prior to initiating naltrexone therapy. If there is any question of opioid use in the past 7-10 days and the patient is not experiencing opioid withdrawal symptoms and/or the urine is negative for opioids, a naloxone challenge test needs to be performed. If a patient receives naltrexone, and an opiate agonist is needed for an emergency situation, large doses of opiate agonists may ultimately overwhelm naltrexone antagonism of opiate receptors. Immediately following administration of exogenous opiate agonists, the opiate plasma concentration may be sufficient to overcome naltrexone competitive blockade, but the patient may experience deeper and more prolonged respiratory depression and thus, may be in danger of respiratory arrest and circulatory collapse. Non-receptor mediated actions like facial swelling, itching, generalized erythema, or bronchoconstriction may occur presumably due to histamine release. A rapidly acting opiate agonist is preferred as the duration of respiratory depression will be shorter. Patients receiving naltrexone may also experience opiate side effects with low doses of opiate agonists. If the opiate agonist is taken in such a way that high concentrations remain in the body beyond the time naltrexone exerts its therapeutic effects, serious side effects may occur. (Moderate) Concomitant use of codeine with bupropion may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of bupropion could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If bupropion is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Bupropion is a strong inhibitor of CYP2D6.
Buspirone: (Moderate) Concomitant use of CNS depressants, such as buspirone, can potentiate the effects of codeine, which may potentially lead to respiratory depression, CNS depression, sedation, or hypotensive responses. If concurrent use of codeine and buspirone is imperative, reduce the dose of one or both drugs. (Minor) In vitro studies showed that therapeutic levels of aspirin, ASA increased the plasma concentrations of free buspirone by 23% through plasma protein binding displacement. In vivo interaction studies with these drugs have not been performed.
Butabarbital: (Major) Concomitant use of codeine with barbiturates may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with barbiturates to only patients for whom alternative treatment options are inadequate. It is recommended to avoid this combination when codeine is being used for cough. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Additionally, concomitant use of codeine with a barbiturate can decrease codeine concentrations, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. Monitor for reduced efficacy of codeine and signs of opioid withdrawal. Discontinuation of a barbiturate may increase the risk of opioid-related adverse reactions, such as fatal respiratory depression. Barbiturates induce CYP3A4. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. (Moderate) Concomitant use of skeletal muscle relaxants with barbiturates can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take barbiturates with another CNS depressant for symptoms of excess sedation.
Butalbital; Acetaminophen: (Major) Concomitant use of codeine with barbiturates may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with barbiturates to only patients for whom alternative treatment options are inadequate. It is recommended to avoid this combination when codeine is being used for cough. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Additionally, concomitant use of codeine with a barbiturate can decrease codeine concentrations, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. Monitor for reduced efficacy of codeine and signs of opioid withdrawal. Discontinuation of a barbiturate may increase the risk of opioid-related adverse reactions, such as fatal respiratory depression. Barbiturates induce CYP3A4. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. (Moderate) Concomitant use of skeletal muscle relaxants with barbiturates can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take barbiturates with another CNS depressant for symptoms of excess sedation.
Butalbital; Acetaminophen; Caffeine: (Major) Concomitant use of codeine with barbiturates may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with barbiturates to only patients for whom alternative treatment options are inadequate. It is recommended to avoid this combination when codeine is being used for cough. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Additionally, concomitant use of codeine with a barbiturate can decrease codeine concentrations, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. Monitor for reduced efficacy of codeine and signs of opioid withdrawal. Discontinuation of a barbiturate may increase the risk of opioid-related adverse reactions, such as fatal respiratory depression. Barbiturates induce CYP3A4. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. (Moderate) Concomitant use of skeletal muscle relaxants with barbiturates can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take barbiturates with another CNS depressant for symptoms of excess sedation. (Minor) Caffeine has been reported to increase the metabolism of aspirin.
Butalbital; Acetaminophen; Caffeine; Codeine: (Major) Concomitant use of codeine with barbiturates may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with barbiturates to only patients for whom alternative treatment options are inadequate. It is recommended to avoid this combination when codeine is being used for cough. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Additionally, concomitant use of codeine with a barbiturate can decrease codeine concentrations, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. Monitor for reduced efficacy of codeine and signs of opioid withdrawal. Discontinuation of a barbiturate may increase the risk of opioid-related adverse reactions, such as fatal respiratory depression. Barbiturates induce CYP3A4. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. (Moderate) Concomitant use of skeletal muscle relaxants with barbiturates can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take barbiturates with another CNS depressant for symptoms of excess sedation. (Minor) Caffeine has been reported to increase the metabolism of aspirin.
Butalbital; Aspirin; Caffeine; Codeine: (Major) Concomitant use of codeine with barbiturates may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with barbiturates to only patients for whom alternative treatment options are inadequate. It is recommended to avoid this combination when codeine is being used for cough. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Additionally, concomitant use of codeine with a barbiturate can decrease codeine concentrations, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. Monitor for reduced efficacy of codeine and signs of opioid withdrawal. Discontinuation of a barbiturate may increase the risk of opioid-related adverse reactions, such as fatal respiratory depression. Barbiturates induce CYP3A4. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. (Moderate) Concomitant use of skeletal muscle relaxants with barbiturates can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take barbiturates with another CNS depressant for symptoms of excess sedation. (Minor) Caffeine has been reported to increase the metabolism of aspirin.
Butorphanol: (Major) Avoid the concomitant use of butorphanol and opiate agonists, such as codeine. Butorphanol is a mixed opiate agonist/antagonist that may block the effects of opiate agonists and reduce analgesic effects of codeine. Butorphanol may cause withdrawal symptoms in patients receiving chronic opiate agonists. Concurrent use of butorphanol with other opiate agonists can cause additive CNS, respiratory, and hypotensive effects. The additive or antagonistic effects are dependent upon the dose of the opiate agonist used; antagonistic effects are more common at low to moderate doses of the opiate agonist. (Moderate) Concomitant use of butorphanol with other CNS depressants, such as carisoprodol, can potentiate the effects of butorphanol on respiratory depression, CNS depression, and sedation.
Caffeine: (Minor) Caffeine has been reported to increase the metabolism of aspirin.
Caffeine; Sodium Benzoate: (Minor) Caffeine has been reported to increase the metabolism of aspirin.
Calcium, Magnesium, Potassium, Sodium Oxybates: (Major) Concomitant use of opioid agonists with sodium oxybate may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medication with sodium oxybate to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. (Major) Sodium oxybate should not be used in combination with CNS depressant anxiolytics, sedatives, and hypnotics or other sedative CNS depressant drugs. Additive CNS depressant effects may be possible when sodium oxybate is used concurrently with skeletal muscle relaxants.
Canagliflozin: (Moderate) Monitor blood glucose during concomitant canagliflozin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Canagliflozin; Metformin: (Moderate) Monitor blood glucose during concomitant canagliflozin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant metformin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Candesartan; Hydrochlorothiazide, HCTZ: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Cannabidiol: (Moderate) Concomitant use of opioid agonists with cannabidiol may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking cannabidiol. Limit the use of opioid pain medications with cannabidiol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. (Moderate) Monitor for excessive sedation and somnolence during coadministration of cannabidiol and carisoprodol. CNS depressants can potentiate the effects of cannabidiol.
Caplacizumab: (Major) Avoid concomitant use of caplacizumab and aspirin when possible. Assess and monitor closely for bleeding if use together is necessary. Interrupt use of caplacizumab if clinically significant bleeding occurs.
Capreomycin: (Major) Since capreomycin is eliminated by the kidney, coadministration with other potentially nephrotoxic drugs, including salicylates, may increase serum concentrations of either drug. Theoretically, the chronic coadministration of these drugs may increase the risk of developing nephrotoxicity, even in patients who have normal renal function. Monitor patients for changes in renal function if these drugs are coadministered.
Capsaicin; Metaxalone: (Major) Concomitant use of opioid agonists with metaxalone may cause respiratory depression, profound sedation, and death. Limit the use of opioid pain medication with metaxalone to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking metaxalone. Educate patients about the risks and symptoms of respiratory depression and sedation. Consider prescribing naloxone for the emergency treatment of opioid overdose. Concomitant use of metaxalone and opioid agonists increases the risk for serotonin syndrome. Avoid concomitant use if possible and monitor for serotonin syndrome if use is necessary.
Captopril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
Captopril; Hydrochlorothiazide, HCTZ: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Carbamazepine: (Moderate) Concomitant use of codeine with carbamazepine can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If carbamazepine is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Carbamazepine is a strong CYP3A4 inducer.
Carbidopa; Levodopa; Entacapone: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including skeletal muscle relaxants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Carbinoxamine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with carbinoxamine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with carbinoxamine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Cariprazine: (Moderate) Concomitant use of opioid agonists lik codeine with cariprazine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with cariprazine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Avoid prescribing opioid cough medication in patients taking cariprazine.
Carisoprodol: (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking carisoprodol.
Cefixime: (Minor) In vitro, salicylates have displaced cefixime from its protein-binding sites, resulting in a 50% increase in free cefixime levels. The clinical significance of this effect is unclear at this time.
Cefotetan: (Minor) Cefotetan has been associated with hypoprothrombinemia and may cause additive effects when given concurrently with salicylates.
Celecoxib: (Major) Concomitant use of analgesic doses of aspirin and celecoxib is generally not recommended due to the increased risk of bleeding. Concurrent use of analgesic doses of aspirin with NSAIDs does not produce a greater therapeutic effect compared to the use of NSAIDs alone. Celecoxib (200 to 400 mg/day) did not interfere with the cardioprotective antiplatelet effect of aspirin (100 to 325 mg) in 2 studies in healthy volunteers and in patients with osteoarthritis and established heart disease. Celecoxib is not a substitute for low dose aspirin for cardiovascular protection. (Moderate) Concomitant use of codeine with celecoxib may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of celecoxib could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If celecoxib is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Celecoxib is an inhibitor of CYP2D6.
Celecoxib; Tramadol: (Major) Concomitant use of analgesic doses of aspirin and celecoxib is generally not recommended due to the increased risk of bleeding. Concurrent use of analgesic doses of aspirin with NSAIDs does not produce a greater therapeutic effect compared to the use of NSAIDs alone. Celecoxib (200 to 400 mg/day) did not interfere with the cardioprotective antiplatelet effect of aspirin (100 to 325 mg) in 2 studies in healthy volunteers and in patients with osteoarthritis and established heart disease. Celecoxib is not a substitute for low dose aspirin for cardiovascular protection. (Major) Concomitant use of codeine with tramadol may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of codeine with tramadol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Additionally, monitor patients for seizures and/or the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. (Major) Concomitant use of tramadol with a skeletal muscle relaxant may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with a skeletal muscle relaxant to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. (Moderate) Concomitant use of codeine with celecoxib may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of celecoxib could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If celecoxib is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Celecoxib is an inhibitor of CYP2D6.
Cenobamate: (Moderate) Concomitant use of codeine with cenobamate may cause excessive sedation and somnolence. Limit the use of codeine with cenobamate to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. Avoid prescribing codeine cough medication in patients taking cenobamate. Additionally, monitor for reduced efficacy of codeine and signs of opioid withdrawal in patients who have developed physical dependence if coadministration with cenobamate is necessary; consider increasing the dose of codeine as needed. If cenobamate is discontinued, consider a dose reduction of codeine and frequently monitor for signs of respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Cenobamate is a moderate CYP3A4 inducer. Concomitant use with cenobamate can increase norcodeine concentrations via increased CYP3A4 metabolism, resulting in decreased metabolism via CYP2D6 resulting in lower morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. (Moderate) Monitor for an altered clinical response to carisoprodol if coadministration with cenobamate is necessary. Carisoprodol is metabolized by CYP2C19 to form meprobamate. Cenobamate is a moderate CYP2C19 inducer. Coadministration could decrease exposure to carisoprodol and increase exposure to meprobamate. The full pharmacological impact of these potential alterations of exposure in terms of either efficacy or safety of carisoprodol is unknown. Additionally, monitor for excessive sedation and somnolence during coadministration of cenobamate and carisoprodol. Concurrent use may result in additive CNS depression.
Ceritinib: (Moderate) Concomitant use of codeine with ceritinib may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6 and, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of ceritinib could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If ceritinib is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Ceritinib is a strong inhibitor of CYP3A4.
Cetirizine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
Cetirizine; Pseudoephedrine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
Chlophedianol; Dexbrompheniramine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with dexbrompheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with dexbrompheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Chlophedianol; Dexchlorpheniramine; Pseudoephedrine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with dexchlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with dexchlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Chloramphenicol: (Moderate) Concomitant use of codeine with chloramphenicol may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of chloramphenicol could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If chloramphenicol is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Chloramphenicol is a strong inhibitor of CYP3A4.
Chlorcyclizine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with chlorcyclizine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with chlorcyclizine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Chlordiazepoxide: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Moderate) Concomitant use of skeletal muscle relaxants with benzodiazepines can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take benzodiazepines with another CNS depressant for symptoms of excess sedation.
Chlordiazepoxide; Amitriptyline: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Moderate) Concomitant use of carisoprodol with tricyclic antidepressants can result in additive CNS depression (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness. (Moderate) Concomitant use of skeletal muscle relaxants with benzodiazepines can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take benzodiazepines with another CNS depressant for symptoms of excess sedation.
Chlordiazepoxide; Clidinium: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Moderate) Concomitant use of skeletal muscle relaxants with benzodiazepines can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take benzodiazepines with another CNS depressant for symptoms of excess sedation.
Chloroprocaine: (Minor) Due to the CNS depression potential of all local anesthetics, they should be used with caution with other agents that can cause respiratory depression, such as opiate agonists.
Chlorothiazide: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Chlorpheniramine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with chlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with chlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Chlorpheniramine; Codeine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with chlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with chlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Chlorpheniramine; Dextromethorphan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with chlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with chlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with chlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with chlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with chlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with chlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Chlorpheniramine; Dihydrocodeine; Phenylephrine: (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking carisoprodol. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with chlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with chlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Chlorpheniramine; Hydrocodone: (Major) Concomitant use of hydrocodone with other CNS depressants may lead to hypotension, profound sedation, coma, respiratory depression and death. Prior to concurrent use of hydrocodone in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. Hydrocodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate hydrocodone at 20 to 30% of the usual dosage in patients that are concurrently receiving another CNS depressant. Also consider a using a lower dose of the CNS depressant. Monitor patients for sedation and respiratory depression. (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking carisoprodol. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with chlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with chlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Chlorpheniramine; Ibuprofen; Pseudoephedrine: (Major) Concomitant use of analgesic doses of aspirin and ibuprofen is generally not recommended due to the increased risk of bleeding and renal impairment. Because there may be an increased risk of cardiovascular events due to the interference of ibuprofen with the antiplatelet effect of aspirin, for patients taking low-dose aspirin for cardioprotection who require analgesics, consider use of an NSAID that does not interfere with the antiplatelet effect of aspirin, or non-NSAID analgesics, as appropriate. Administer single doses of ibuprofen at least 2 to 4 hours or more after aspirin and wait 8 hours after ibuprofen administration before administering aspirin to avoid significant interference. Monitor for signs and symptoms of renal impairment. Pharmacodynamic studies have demonstrated interference with the antiplatelet activity of aspirin when ibuprofen 400 mg 3 times daily is administered with enteric-coated low-dose aspirin. The interaction exists even after ibuprofen 400 mg once daily, particularly when ibuprofen is dosed prior to aspirin. The interaction is alleviated if immediate-release low-dose aspirin is dosed at least 2 hours prior to a once daily regimen of ibuprofen; however, this finding cannot be extended to enteric-coated low-dose aspirin. A decrease in antiplatelet activity (53%) was observed when ibuprofen 400 mg once daily was administered 2 hours before low-dose immediate-release aspirin 81 mg/day for 6 days. An interaction was still observed, but minimized, when ibuprofen 400 mg once daily was administered as early as 8 hours before immediate-release aspirin (90.7%). There was no interaction with the antiplatelet activity of aspirin when ibuprofen 400 mg once daily was administered 2 hours after immediate-release aspirin (99.2%). In another study of low-dose immediate-release aspirin 81 mg/day and ibuprofen 400 mg 3 times daily (1, 7, and 13 hours post-aspirin dose) for 10 consecutive days, there was no interaction with the antiplatelet activity of aspirin (98.3%); however, there were individuals with aspirin antiplatelet activity below 95%, with the lowest being 90.2%. When a similarly designed study was conducted with enteric-coated aspirin 81 mg/day for 6 days and ibuprofen 400 mg 3 times daily (2, 7 and 12 h post-aspirin dose) for 6 days, there was an interaction with the antiplatelet activity at 24 hours after the day 6 aspirin dose (67%). Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone. Ibuprofen is not a substitute for low dose aspirin for cardiovascular protection. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with chlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with chlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Chlorpheniramine; Phenylephrine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with chlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with chlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Chlorpheniramine; Pseudoephedrine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with chlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with chlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Chlorpromazine: (Major) Concomitant use of opioid agonists with chlorpromazine may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking chlorpromazine. Limit the use of opioid pain medications with chlorpromazine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. (Moderate) Phenothiazines can potentiate the CNS-depressant action of other drugs such as skeletal muscle relaxants. Caution should be exercised during simultaneous use of these agents due to potential for additive hypotension and excessive CNS effects (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Chlorpropamide: (Moderate) Monitor blood glucose during concomitant sulfonylurea and aspirin use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Chlorthalidone: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Chlorthalidone; Clonidine: (Major) Concomitant use of opioid agonists with clonidine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with clonidine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Chlorzoxazone: (Major) Concomitant use of opioid agonists with chlorzoxazone may cause excessive sedation and somnolence. Limit the use of opioid pain medications with chlorzoxazone to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking chlorzoxazone.
Cidofovir: (Contraindicated) The concomitant administration of cidofovir and NSAIDs, such as aspirin, is contraindicated due to the potential for increased nephrotoxicity. Aspirin should be discontinued 7 days prior to beginning cidofovir.
Cilostazol: (Moderate) Use caution with the coadministration of aspirin and cilostazol. Although the short-term (<= 4 days) coadministration of aspirin and cilostazol increased the inhibition of ADP-induced platelet aggregation by 22% to 37% compared to aspirin or cilostazol use alone, no clinically significant effect on PT, aPTT, or bleeding time was observed compared to aspirin alone. In clinical trials, there was no apparent increase in hemorrhagic adverse effects in patients taking cilostazol and aspirin compared to aspirin alone. The effects of long-term coadministration are unknown. Monitor for bleeding during concomitant therapy.
Cimetidine: (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as cimetidine, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects. (Minor) Cimetidine may inhibit the conversion of codeine to morphine, codeine's active metabolite, via the CYP2D6 hepatic isoenzyme and therefore may decrease the ability for codeine to produce analgesic effect.
Cinacalcet: (Moderate) Concomitant use of codeine with cinacalcet may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of cinacalcet could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If cinacalcet is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Cinacalcet is a moderate inhibitor of CYP2D6.
Ciprofloxacin: (Moderate) Concomitant use of codeine with ciprofloxacin may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6 and, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of ciprofloxacin could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If ciprofloxacin is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Ciprofloxacin is a moderate inhibitor of CYP3A4.
Citalopram: (Moderate) Serotonin syndrome can occur during concomitant use of opiate agonists like codeine with serotonergic drugs, such as citalopram. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Citric Acid; Potassium Citrate; Sodium Citrate: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid. (Moderate) Urinary alkalinizing agents, like potassium citrate, increase the excretion of salicylates by increasing renal clearance.
Clarithromycin: (Moderate) Concomitant use of codeine with clarithromycin may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of clarithromycin could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If clarithromycin is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Clarithromycin is a strong inhibitor of CYP3A4.
Clemastine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with clemastine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with clemastine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Clobazam: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines.
Clomipramine: (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Moderate) Clomipramine may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. This may increase the risk for an upper GI bleed. (Moderate) Concomitant use of carisoprodol with tricyclic antidepressants can result in additive CNS depression (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Clonazepam: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Moderate) Concomitant use of skeletal muscle relaxants with benzodiazepines can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take benzodiazepines with another CNS depressant for symptoms of excess sedation.
Clonidine: (Major) Concomitant use of opioid agonists with clonidine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with clonidine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Clopidogrel: (Moderate) Coadministration of opioid agonists, such as codeine, delay and reduce the absorption of clopidogrel resulting in reduced exposure to active metabolites and diminished inhibition of platelet aggregation. Consider the use of a parenteral antiplatelet agent in acute coronary syndrome patients requiring an opioid agonist. Coadministration of intravenous morphine decreased the Cmax and AUC of clopidogrel's active metabolites by 34%. Time required for maximal inhibition of platelet aggregation (median 3 hours vs. 1.25 hours) was significantly delayed; times up to 5 hours were reported. Inhibition of platelet plug formation was delayed and residual platelet aggregation was significantly greater 1 to 4 hours after morphine administration. (Moderate) Monitor for bleeding if aspirin and clopidogrel are used together as concomitant has an additive effect on platelet function.
Clorazepate: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Moderate) Concomitant use of skeletal muscle relaxants with benzodiazepines can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take benzodiazepines with another CNS depressant for symptoms of excess sedation.
Clozapine: (Moderate) Concomitant use of central nervous system depressants, such as clozapine, can potentiate the effects of codeine, which may lead to respiratory depression, CNS depression, sedation, or hypotensive responses. Combining clozapine with opiate agonists may also lead to additive effects on intestinal motility or bladder function, resulting in constipation or urinary retention. (Moderate) Skeletal muscle relaxants should be combined cautiously with clozapine because they could cause additive depressant effects and possible respiratory depression or hypotension.
Cobicistat: (Moderate) Concomitant use of codeine with cobicistat may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of cobicistat could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If cobicistat is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Cobicistat is a strong inhibitor of CYP3A4.
Codeine; Phenylephrine; Promethazine: (Major) Concomitant use of opioid agonists with promethazine may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking promethazine. Limit the use of opioid pain medications with promethazine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce the opioid dose by one-quarter to one-half; use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. (Moderate) Phenothiazines can potentiate the CNS-depressant action of other drugs such as skeletal muscle relaxants. Caution should be exercised during simultaneous use of these agents due to potential for additive hypotension and excessive CNS effects (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Codeine; Promethazine: (Major) Concomitant use of opioid agonists with promethazine may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking promethazine. Limit the use of opioid pain medications with promethazine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce the opioid dose by one-quarter to one-half; use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of ex cessive CNS depression. (Moderate) Phenothiazines can potentiate the CNS-depressant action of other drugs such as skeletal muscle relaxants. Caution should be exercised during simultaneous use of these agents due to potential for additive hypotension and excessive CNS effects (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Colistimethate, Colistin, Polymyxin E: (Major) Theoretically, the chronic coadministration of these drugs may increase the risk of developing nephrotoxicity, even in patients who have normal renal function. Monitor patients for changes in renal function if these drugs are coadministered. Since colistimethate sodium is eliminated by the kidney, coadministration with other potentially nephrotoxic drugs, including salicylates, may increase serum concentrations of either drug.
Colistin: (Major) Theoretically, the chronic coadministration of these drugs may increase the risk of developing nephrotoxicity, even in patients who have normal renal function. Monitor patients for changes in renal function if these drugs are coadministered. Since colistimethate sodium is eliminated by the kidney, coadministration with other potentially nephrotoxic drugs, including salicylates, may increase serum concentrations of either drug.
Collagenase: (Moderate) Cautious use of injectable collagenase by patients taking more than 150 mg/day of aspirin is advised. The efficacy and safety of administering injectable collagenase to a patient taking more than 150 mg/day of aspirin within 7 days before the injection are unknown. Receipt of injectable collagenase may cause an ecchymosis or bleeding at the injection site.
COMT inhibitors: (Major) Concomitant use of opioid agonists with COMT inhibitors may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking COMT inhibitors. Limit the use of opioid pain medications with COMT inhibitors to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including skeletal muscle relaxants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Conivaptan: (Moderate) Concomitant use of codeine with conivaptan may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of conivaptan could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If conivaptan is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Conivaptan is a moderate inhibitor of CYP3A.
Corticosteroids: (Moderate) Monitor for gastrointestinal toxicity during concurrent corticosteroid and salicylate use. Concomitant use increases the risk of GI bleeding. In patients receiving concomitant corticosteroids and chronic use of salicylates, withdrawal of corticosteroids may result in salicylism because corticosteroids enhance renal clearance of salicylates and their withdrawal is followed by return to normal rates of renal clearance.
Crizotinib: (Moderate) Concomitant use of codeine with crizotinib may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of crizotinib could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If crizotinib is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Crizotinib is a moderate inhibitor of CYP3A.
Crofelemer: (Moderate) Pharmacodynamic interactions between crofelemer and opiate agonists are theoretically possible. Crofelemer does not affect GI motility mechanisms, but does have antidiarrheal effects. Patients taking medications that decrease GI motility, such as opiate agonists, may be at greater risk for serious complications from crofelemer, such as constipation with chronic use. Use caution and monitor GI symptoms during coadministration.
Cyclizine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with cyclizine may cause excessive sedation and somnolence. Limit the use of opioid pain medications with cyclizine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression.
Cyclobenzaprine: (Major) Concomitant use of codeine with cyclobenzaprine may cause respiratory depression, hypotension, profound sedation, and death and increase the risk for serotonin syndrome and anticholinergic effects. Limit the use of opioid pain medications with cyclobenzaprine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking cyclobenzaprine. Monitor patients for serotonin syndrome if concomitant use is necessary, particularly during treatment initiation and dosage increases. If serotonin syndrome occurs, consider discontinuation of therapy. The concomitant use of serotonergic drugs increases the risk of serotonin syndrome. Monitor for signs of urinary retention or reduced gastric motility during coadministration. The concomitant use of anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Cyclosporine: (Moderate) Concomitant use of codeine with cyclosporine may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of cyclosporine could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If cyclosporine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Cyclosporine is a moderate inhibitor of CYP3A4. (Minor) Due to the inhibition of renal prostaglandins by salicylates, concurrent use of salicylates and other nephrotoxic agents like cyclosporine may lead to additive nephrotoxicity.
Cyproheptadine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with cyproheptadine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with cyproheptadine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Dabigatran: (Major) Educate patients about the signs of increased bleeding and the need to report these signs to a healthcare provider immediately if coadministration of dabigatran and aspirin or another salicylate is necessary. Dabigatran can cause significant and, sometimes, fatal bleeding. This risk may be increased by concurrent use of chronic salicylate therapy.
Dabrafenib: (Moderate) Concomitant use of codeine with dabrafenib can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If dabrafenib is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Dabrafenib is a moderate CYP3A4 inducer.
Dacomitinib: (Moderate) Concomitant use of codeine with dacomitinib may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of dacomitinib could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If dacomitinib is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Dacomitinib is a strong inhibitor of CYP2D6.
Dalfopristin; Quinupristin: (Moderate) Concomitant use of codeine with dalfopristin; quinupristin may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of dalfopristin; quinupristin could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If dalfopristin; quinupristin is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Dalfopristin; quinupristin is a weak inhibitor of CYP3A4.
Dalteparin: (Moderate) An additive risk of bleeding may be seen in patients receiving a low molecular weight heparin in combination with other agents known to increase the risk of bleeding such as salicylates. Monitor clinical and laboratory response closely during concurrent use.
Danazol: (Moderate) Concomitant use of codeine with danazol may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of danazol could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If danazol is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Danazol is a moderate inhibitor of CYP3A4. (Moderate) Danazol can decrease hepatic synthesis of procoagulant factors, increasing the possibility of bleeding when used concurrently with platelet inhibitors.
Dantrolene: (Major) Concomitant use of opioid agonists with dantrolene may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid agonists with dantrolene to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking dantrolene.
Dapagliflozin: (Moderate) Monitor blood glucose during concomitant dapagliflozin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Dapagliflozin; Metformin: (Moderate) Monitor blood glucose during concomitant dapagliflozin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant metformin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Dapagliflozin; Saxagliptin: (Moderate) Monitor blood glucose during concomitant dapagliflozin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant saxagliptin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Daratumumab; Hyaluronidase: (Minor) Salicylates, when given in large systemic doses, may render tissues partially resistant to the action of hyaluronidase. Patients receiving these medications may require larger amounts of hyaluronidase for equivalent dispersing effect.
Daridorexant: (Major) Concomitant use of opiate agonists with daridorexant may cause excessive sedation and somnolence. Limit the use of opiates with daridorexant to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. Avoid prescribing cough medicines that contain opiates in patients taking daridorexant.
Darifenacin: (Moderate) Concomitant use of codeine with darifenacin may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Avoid this combination when codeine is being used for cough; consider alternative therapy for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of darifenacin could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If darifenacin is discontinued, monitor the patient carefully and consider reducing the codeine dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Darifenacin is a moderate inhibitor of CYP2D6. In addition, the concomitant use of these drugs together may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Darifenacin has anticholinergic actions that may produce additive effects. Both agents may also cause drowsiness or blurred vision, and patients should use care in driving or performing other hazardous tasks until the effects of the drugs are known.
Darunavir: (Moderate) Concomitant use of codeine with darunavir may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of darunavir could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If darunavir is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Darunavir is a strong inhibitor of CYP3A4.
Darunavir; Cobicistat: (Moderate) Concomitant use of codeine with cobicistat may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of cobicistat could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If cobicistat is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Cobicistat is a strong inhibitor of CYP3A4. (Moderate) Concomitant use of codeine with darunavir may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of darunavir could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If darunavir is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Darunavir is a strong inhibitor of CYP3A4.
Darunavir; Cobicistat; Emtricitabine; Tenofovir alafenamide: (Moderate) Concomitant use of codeine with cobicistat may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of cobicistat could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If cobicistat is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Cobicistat is a strong inhibitor of CYP3A4. (Moderate) Concomitant use of codeine with darunavir may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of darunavir could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If darunavir is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Darunavir is a strong inhibitor of CYP3A4.
Deferasirox: (Moderate) Because gastric ulceration and GI bleeding have been reported in patients taking deferasirox, use caution when coadministering with other drugs known to increase the risk of peptic ulcers or gastric hemorrhage including salicylates.
Defibrotide: (Contraindicated) Coadministration of defibrotide with antithrombotic agents like aspirin is contraindicated. The pharmacodynamic activity and risk of hemorrhage with antithrombotic agents are increased if coadministered with defibrotide. If therapy with defibrotide is necessary, discontinue antithrombotic agents prior to initiation of defibrotide therapy. Consider delaying the onset of defibrotide treatment until the effects of the antithrombotic agent have abated.
Delavirdine: (Moderate) Concomitant use of codeine with delavirdine may alter codeine plasma concentrations, resulting in an unpredictable effect such as reduced efficacy or symptoms of opioid withdrawal or prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage adjustment of codeine until stable drug effects are achieved. Discontinuation of delavirdine could alter codeine plasma concentrations, resulting in an unpredictable effect such as prolonged opioid adverse reactions or decreased opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If delavirdine is discontinued, monitor the patient carefully and consider adjusting the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Delavirdine is a strong inhibitor of CYP3A4 and a moderate inhibitor of CYP2D6. CYP3A4 inhibitors may increase codeine-related adverse effects while CYP2D6 inhibitors may reduce efficacy. (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as delavirdine, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
Desflurane: (Moderate) Concurrent use with opiate agonists can decrease the minimum alveolar concentration (MAC) of desflurane needed to produce anesthesia.
Desipramine: (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Moderate) Concomitant use of carisoprodol with tricyclic antidepressants can result in additive CNS depression (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Desmopressin: (Major) Additive hyponatremic effects may be seen in patients treated with desmopressin and drugs associated with water intoxication, hyponatremia, or SIADH including opiate agonists. Use combination with caution, and monitor patients for signs and symptoms of hyponatremia.
Desvenlafaxine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and desvenlafaxine because of the potential risk of serotonin syndrome and decreased codeine efficacy. Discontinue codeine if serotonin syndrome is suspected. Additionally, concomitant use of codeine with desvenlafaxine may decrease codeine plasma concentrations resulting in reduced efficacy or symptoms of opioid withdrawal. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of desvenlafaxine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If desvenlafaxine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Desvenlafaxine is a weak inhibitor of CYP2D6.
Deutetrabenazine: (Major) Concomitant use of opiate agonists with deutetrabenazine may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with deutetrabenazine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking deutetrabenazine, use a lower initial dose of the opiate and titrate to clinical response. If deutetrabenazine is prescribed for a patient taking an opiate agonist, use a lower initial dose of deutetrabenazine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking deutetrabenazine. (Moderate) Advise patients that concurrent use of deutetrabenazine and drugs that can cause CNS depression, such as carisoprodol, may have additive effects and worsen drowsiness or sedation.
Dexamethasone: (Moderate) Monitor for reduced efficacy of codeine and signs of opioid withdrawal in patients who have developed physical dependence if coadministration with dexamethasone is necessary; consider increasing the dose of codeine as needed. It is recommended to avoid this combination when codeine is being used for cough. If dexamethasone is discontinued, consider a dose reduction of codeine and frequently monitor for signs of respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Dexamethasone is a weak CYP3A inducer. Concomitant use with dexamethasone can increase norcodeine levels via increased CYP3A metabolism, resulting in decreased metabolism via CYP2D6 resulting in lower morphine levels; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence.
Dexbrompheniramine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with dexbrompheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with dexbrompheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Dexbrompheniramine; Pseudoephedrine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with dexbrompheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with dexbrompheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Dexchlorpheniramine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with dexchlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with dexchlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Dexchlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with dexchlorpheniramine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with dexchlorpheniramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Dexmedetomidine: (Moderate) Concomitant use of opioid agonists with dexmedetomidine may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medication with dexmedetomidine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. (Moderate) Due to the anesthetic effects of dexmedetomidine, concurrent use with other CNS depressants, such as skeletal muscle relaxants, could result in additive sedative effects and possibly prolong recovery from anesthesia. Dosage adjustments of either or both medications may be necessary.
Dextroamphetamine: (Moderate) If concomitant use of codeine and amphetamines is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Dextromethorphan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Dextromethorphan; Bupropion: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Concomitant use of codeine with bupropion may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of bupropion could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If bupropion is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Bupropion is a strong inhibitor of CYP2D6.
Dextromethorphan; Diphenhydramine; Phenylephrine: (Major) Reserve concomitant use of opioids and diphenhydramine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant.
Dextromethorphan; Guaifenesin: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Dextromethorphan; Guaifenesin; Phenylephrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Dextromethorphan; Guaifenesin; Potassium Guaiacolsulfonate: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Dextromethorphan; Guaifenesin; Pseudoephedrine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Dextromethorphan; Quinidine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Concomitant use of codeine with quinidine may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of quinidine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If quinidine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Quinidine is a strong inhibitor of CYP2D6.
Diazepam: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If parental diazepam is used with an opiate agonist, reduce the opiate agonist dosage by at least 1/3. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Moderate) Concomitant use of skeletal muscle relaxants with benzodiazepines can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take benzodiazepines with another CNS depressant for symptoms of excess sedation.
Dichlorphenamide: (Major) Dichlorphenamide is contraindicated with the concomitant use of high dose aspirin, ASA and should be used cautiously in patients receiving low dose aspirin. Dichlorphenamide may cause an elevation in salicylate concentrations in patients receiving aspirin. Adverse reactions including anorexia, tachypnea, lethargy, and coma have been reported with the concomitant use of dichlorphenamide and high dose aspirin.
Diclofenac: (Major) Concomitant use of analgesic doses of aspirin and diclofenac is generally not recommended due to the increased risk of bleeding and renal impairment. Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone. Diclofenac is not a substitute for low dose aspirin for cardiovascular protection.
Diclofenac; Misoprostol: (Major) Concomitant use of analgesic doses of aspirin and diclofenac is generally not recommended due to the increased risk of bleeding and renal impairment. Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone. Diclofenac is not a substitute for low dose aspirin for cardiovascular protection.
Dicloxacillin: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Dicyclomine: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and dicyclomine use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Difelikefalin: (Major) Avoid concomitant use of opioids and other CNS depressants, such as difelikefalin. Concomitant use can increase the risk of respiratory depression, hypotension, profound sedation, and death. If alternate treatment options are inadequate and coadministration is necessary, limit dosages and durations to the minimum required, monitor patients closely for respiratory depression and sedation, and consider prescribing naloxone for the emergency treatment of opioid overdose. (Moderate) Monitor for dizziness, somnolence, mental status changes, and gait disturbances if concomitant use of difelikefalin with CNS depressants is necessary. Concomitant use may increase the risk for these adverse reactions.
Diflunisal: (Major) The concurrent use of diflunisal and salicylates is not recommended due to the increased risk of gastrointestinal toxicity with little or no increase in anti-inflammatory efficacy.
Diltiazem: (Moderate) Concomitant use of codeine with diltiazem may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of diltiazem could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If diltiazem is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Diltiazem is a moderate inhibitor of CYP3A4.
Dimenhydrinate: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with dimenhydrinate may cause excessive sedation and somnolence. Limit the use of opioid pain medication with dimenhydrinate to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Diphenhydramine: (Major) Reserve concomitant use of opioids and diphenhydramine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant.
Diphenhydramine; Ibuprofen: (Major) Concomitant use of analgesic doses of aspirin and ibuprofen is generally not recommended due to the increased risk of bleeding and renal impairment. Because there may be an increased risk of cardiovascular events due to the interference of ibuprofen with the antiplatelet effect of aspirin, for patients taking low-dose aspirin for cardioprotection who require analgesics, consider use of an NSAID that does not interfere with the antiplatelet effect of aspirin, or non-NSAID analgesics, as appropriate. Administer single doses of ibuprofen at least 2 to 4 hours or more after aspirin and wait 8 hours after ibuprofen administration before administering aspirin to avoid significant interference. Monitor for signs and symptoms of renal impairment. Pharmacodynamic studies have demonstrated interference with the antiplatelet activity of aspirin when ibuprofen 400 mg 3 times daily is administered with enteric-coated low-dose aspirin. The interaction exists even after ibuprofen 400 mg once daily, particularly when ibuprofen is dosed prior to aspirin. The interaction is alleviated if immediate-release low-dose aspirin is dosed at least 2 hours prior to a once daily regimen of ibuprofen; however, this finding cannot be extended to enteric-coated low-dose aspirin. A decrease in antiplatelet activity (53%) was observed when ibuprofen 400 mg once daily was administered 2 hours before low-dose immediate-release aspirin 81 mg/day for 6 days. An interaction was still observed, but minimized, when ibuprofen 400 mg once daily was administered as early as 8 hours before immediate-release aspirin (90.7%). There was no interaction with the antiplatelet activity of aspirin when ibuprofen 400 mg once daily was administered 2 hours after immediate-release aspirin (99.2%). In another study of low-dose immediate-release aspirin 81 mg/day and ibuprofen 400 mg 3 times daily (1, 7, and 13 hours post-aspirin dose) for 10 consecutive days, there was no interaction with the antiplatelet activity of aspirin (98.3%); however, there were individuals with aspirin antiplatelet activity below 95%, with the lowest being 90.2%. When a similarly designed study was conducted with enteric-coated aspirin 81 mg/day for 6 days and ibuprofen 400 mg 3 times daily (2, 7 and 12 h post-aspirin dose) for 6 days, there was an interaction with the antiplatelet activity at 24 hours after the day 6 aspirin dose (67%). Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone. Ibuprofen is not a substitute for low dose aspirin for cardiovascular protection. (Major) Reserve concomitant use of opioids and diphenhydramine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant.
Diphenhydramine; Naproxen: (Major) Concomitant use of analgesic doses of aspirin and naproxen is generally not recommended due to the increased risk of bleeding and renal impairment. Because there may be an increased risk of cardiovascular events after discontinuation of naproxen due to the interference with the antiplatelet effect of aspirin during the washout period, for patients taking low-dose aspirin for cardioprotection who require intermittent analgesics, consider use of an NSAID that does not interfere with the antiplatelet effect of aspirin, or non-NSAID analgesics as appropriate. A pharmacodynamic study demonstrated that lower dose naproxen (220mg/day or 220mg twice daily) interfered with the antiplatelet effect of low-dose immediate-release aspirin, with the interaction most marked during the washout period of naproxen. There is reason to expect that the interaction would be present with prescription doses of naproxen or with enteric-coated low-dose aspirin; however, the peak interference with aspirin function may be later than observed in the study due to the longer washout period. A decrease in antiplatelet activity was observed at 24 hours after 10 days of naproxen 220 mg/day with low-dose immediate-release aspirin 81 mg/day (93.1%) vs. aspirin alone (98.7%). The interaction was observed even after discontinuation of naproxen on day 11 while aspirin therapy continued but normalized by day 13. The interaction was greater when naproxen was given 30 minutes before aspirin (87.7% vs. 98.7%) and minimal when aspirin was administered 30 minutes before naproxen (95.4% vs. 98.7%). The interaction was minimal at 24 hours after day 10 when naproxen 220 mg twice daily was given 30 minutes before low-dose immediate-release aspirin (95.7% vs. 98.7%); however, the interaction was greater on day 11 after naproxen discontinuation (84.3% vs. 98.7%) and did not normalize by day 13 (90.7% vs. 98.5%). Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone. Naproxen is not a substitute for low dose aspirin for cardiovascular protection. (Major) Reserve concomitant use of opioids and diphenhydramine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant.
Diphenhydramine; Phenylephrine: (Major) Reserve concomitant use of opioids and diphenhydramine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant.
Diphenoxylate; Atropine: (Major) Reserve concomitant use of codeine and atropine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Concurrent administration of diphenoxylate/difenoxin with carisoprodol can potentiate the CNS-depressant effects of diphenoxylate/difenoxin. Use caution during coadministration. (Moderate) Concurrent administration of diphenoxylate/difenoxin with other opiate agonists can potentiate the CNS-depressant effects of diphenoxylate/difenoxin. Use caution during coadministration. In addition, diphenoxylate/difenoxin use may cause constipation; cases of severe GI reactions including toxic megacolon and adynamic ileus have been reported. Reduced GI motility when combined with opiate agonists may increase the risk of serious GI related adverse events.
Dipyridamole: (Moderate) Although aspirin may be used in combination with dipyridamole, both drugs are associated with bleeding. Monitor for bleeding during concomitant therapy.
Dolasetron: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Doravirine; Lamivudine; Tenofovir disoproxil fumarate: (Major) Renal impairment, which may include hypophosphatemia, has been reported with the use of tenofovir disoproxil fumarate with a majority of the cases occurring in patients who have underlying systemic or renal disease or who are concurrently taking nephrotoxic agents. Tenofovir should be avoided with concurrent or recent use of a nephrotoxic agent; patients receiving concomitant nephrotoxic agents, like salicylates should be carefully monitored for changes in serum creatinine and phosphorus.
Doxepin: (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Moderate) Concomitant use of carisoprodol with tricyclic antidepressants can result in additive CNS depression ( sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Doxylamine: (Major) Reserve concomitant use of opioids and doxylamine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant.
Doxylamine; Pyridoxine: (Major) Reserve concomitant use of opioids and doxylamine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant.
Dronabinol: (Moderate) Concomitant use of opioid agonists with dronabinol may cause excessive sedation and somnolence. Limit the use of opioid pain medication with dronabinol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. (Moderate) Concomitant use of skeletal muscle relaxants with dronabinol can result in additive CNS depression and dizziness, which can impair the ability to undertake tasks requiring mental alertness. Utilize appropriate caution if these drugs are given together.
Dronedarone: (Moderate) Concomitant use of codeine with dronedarone may alter codeine plasma concentrations, resulting in an unpredictable effect such as reduced efficacy or symptoms of opioid withdrawal or prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage adjustment of codeine until stable drug effects are achieved. Discontinuation of dronedarone could alter codeine plasma concentrations, resulting in an unpredictable effect such as prolonged opioid adverse reactions or decreased opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If dronedarone is discontinued, monitor the patient carefully and consider adjusting the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Dronedarone is a moderate inhibitor of CYP3A and CYP2D6. CYP3A inhibitors may increase codeine-related adverse effects while CYP2D6 inhibitors may reduce efficacy.
Droperidol: (Major) Central nervous system depressants, such as carisoprodol have additive or potentiating effects with droperidol. Following administration of droperidol, lower doses of the other CNS depressant should be used. (Major) Concomitant use of opioid agonists with droperidol may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking droperidol. Limit the use of opioid pain medications with droperidol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression.
Duloxetine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and duloxetine because of the potential risk of serotonin syndrome, reduced codeine efficacy, and potential for opioid withdrawal symptoms. Discontinue codeine if serotonin syndrome is suspected. It is recommended to avoid this combination when codeine is being used for cough. Concomitant use may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of duloxetine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If duloxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Duloxetine is a moderate inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Edoxaban: (Major) Monitor for bleeding in patients who require chronic treatment with aspirin. Concomitant use of edoxaban with drugs that affect hemostasis, such as aspirin, may increase the risk of bleeding. The coadministration of aspirin (100 mg or 325 mg) and edoxaban increased bleeding time relative to that seen with either drug alone.
Efavirenz: (Moderate) Concomitant use of codeine with efavirenz can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If efavirenz is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Efavirenz is a moderate CYP3A4 inducer. (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as efavirenz, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
Efavirenz; Emtricitabine; Tenofovir Disoproxil Fumarate: (Major) Renal impairment, which may include hypophosphatemia, has been reported with the use of tenofovir disoproxil fumarate with a majority of the cases occurring in patients who have underlying systemic or renal disease or who are concurrently taking nephrotoxic agents. Tenofovir should be avoided with concurrent or recent use of a nephrotoxic agent; patients receiving concomitant nephrotoxic agents, like salicylates should be carefully monitored for changes in serum creatinine and phosphorus. (Moderate) Concomitant use of codeine with efavirenz can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If efavirenz is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Efavirenz is a moderate CYP3A4 inducer. (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as efavirenz, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
Efavirenz; Lamivudine; Tenofovir Disoproxil Fumarate: (Major) Renal impairment, which may include hypophosphatemia, has been reported with the use of tenofovir disoproxil fumarate with a majority of the cases occurring in patients who have underlying systemic or renal disease or who are concurrently taking nephrotoxic agents. Tenofovir should be avoided with concurrent or recent use of a nephrotoxic agent; patients receiving concomitant nephrotoxic agents, like salicylates should be carefully monitored for changes in serum creatinine and phosphorus. (Moderate) Concomitant use of codeine with efavirenz can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If efavirenz is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Efavirenz is a moderate CYP3A4 inducer. (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as efavirenz, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
Efgartigimod Alfa; Hyaluronidase: (Minor) Salicylates, when given in large systemic doses, may render tissues partially resistant to the action of hyaluronidase. Patients receiving these medications may require larger amounts of hyaluronidase for equivalent dispersing effect.
Elagolix: (Moderate) Concomitant use of codeine with elagolix can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If elagolix is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Elagolix is a weak to moderate CYP3A4 inducer.
Elagolix; Estradiol; Norethindrone acetate: (Moderate) Concomitant use of codeine with elagolix can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If elagolix is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Elagolix is a weak to moderate CYP3A4 inducer.
Elbasvir; Grazoprevir: (Moderate) Administering codeine with elbasvir; grazoprevir may result in elevated codeine plasma concentrations. Codeine is a substrate of CYP3A; grazoprevir is a weak CYP3A inhibitor. If these drugs are used together, closely monitor for signs of adverse events.
Eletriptan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor agonists. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Eliglustat: (Moderate) Concomitant use of codeine with eliglustat may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of eliglustat could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If eliglustat is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Eliglustat is a moderate inhibitor of CYP2D6.
Eluxadoline: (Major) Avoid use of eluxadoline with medications that may cause constipation, such as codeine. Opioids increase the tone and decrease the propulsive contractions of the smooth muscle within the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect. Closely monitor for increased side effects if these drugs are administered together.
Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide: (Moderate) Concomitant use of codeine with cobicistat may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of cobicistat could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If cobicistat is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Cobicistat is a strong inhibitor of CYP3A4.
Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Disoproxil Fumarate: (Major) Renal impairment, which may include hypophosphatemia, has been reported with the use of tenofovir disoproxil fumarate with a majority of the cases occurring in patients who have underlying systemic or renal disease or who are concurrently taking nephrotoxic agents. Tenofovir should be avoided with concurrent or recent use of a nephrotoxic agent; patients receiving concomitant nephrotoxic agents, like salicylates should be carefully monitored for changes in serum creatinine and phosphorus. (Moderate) Concomitant use of codeine with cobicistat may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of cobicistat could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If cobicistat is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Cobicistat is a strong inhibitor of CYP3A4.
Empagliflozin: (Moderate) Monitor blood glucose during concomitant empagliflozin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Empagliflozin; Linagliptin: (Moderate) Monitor blood glucose during concomitant empagliflozin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant linagliptin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Empagliflozin; Linagliptin; Metformin: (Moderate) Monitor blood glucose during concomitant empagliflozin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant linagliptin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant metformin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Empagliflozin; Metformin: (Moderate) Monitor blood glucose during concomitant empagliflozin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant metformin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Emtricitabine; Rilpivirine; Tenofovir Disoproxil Fumarate: (Major) Renal impairment, which may include hypophosphatemia, has been reported with the use of tenofovir disoproxil fumarate with a majority of the cases occurring in patients who have underlying systemic or renal disease or who are concurrently taking nephrotoxic agents. Tenofovir should be avoided with concurrent or recent use of a nephrotoxic agent; patients receiving concomitant nephrotoxic agents, like salicylates should be carefully monitored for changes in serum creatinine and phosphorus.
Emtricitabine; Tenofovir Disoproxil Fumarate: (Major) Renal impairment, which may include hypophosphatemia, has been reported with the use of tenofovir disoproxil fumarate with a majority of the cases occurring in patients who have underlying systemic or renal disease or who are concurrently taking nephrotoxic agents. Tenofovir should be avoided with concurrent or recent use of a nephrotoxic agent; patients receiving concomitant nephrotoxic agents, like salicylates should be carefully monitored for changes in serum creatinine and phosphorus.
Enalapril, Enalaprilat: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
Enalapril; Hydrochlorothiazide, HCTZ: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Enoxaparin: (Moderate) An additive risk of bleeding may be seen in patients receiving a low molecular weight heparin in combination with other agents known to increase the risk of bleeding such as salicylates. Monitor clinical and laboratory response closely during concurrent use.
Entacapone: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including skeletal muscle relaxants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Enzalutamide: (Moderate) Concomitant use of codeine with enzalutamide can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If enzalutamide is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Enzalutamide is a strong CYP3A4 inducer. (Minor) Monitor for decreased efficacy of carisoprodol if coadministration with enzalutamide is necessary. Carisoprodol is a CYP2C19 substrate and enzalutamide is a moderate CYP2C19 inducer. The full pharmacological impact of this interaction is unknown.
Epoprostenol: (Moderate) When used concurrently with platelet inhibitors, epoprostenol may increase the risk of bleeding.
Eprosartan; Hydrochlorothiazide, HCTZ: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Eptifibatide: (Moderate) Unless contraindicated, aspirin is used in combination with eptifibatide. However, both drugs are associated with bleeding. Monitor for bleeding during concomitant therapy.
Ergotamine; Caffeine: (Minor) Caffeine has been reported to increase the metabolism of aspirin.
Ertugliflozin; Metformin: (Moderate) Monitor blood glucose during concomitant metformin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Ertugliflozin; Sitagliptin: (Moderate) Monitor blood glucose during concomitant sitagliptin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Erythromycin: (Moderate) Concomitant use of codeine with erythromycin may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of erythromycin could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If erythromycin is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Erythromycin is a moderate inhibitor of CYP3A4.
Escitalopram: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and escitalopram because of the potential risk of serotonin syndrome. Discontinue codeine if serotonin syndrome is suspected. Additionally, concomitant use of codeine with escitalopram may decrease codeine plasma concentrations resulting in reduced efficacy or symptoms of opioid withdrawal. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of escitalopram could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If escitalopram is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Escitalopram is a weak inhibitor of CYP2D6. (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Esketamine: (Major) Closely monitor patients receiving esketamine and skeletal muscle relaxants for sedation and other CNS depressant effects. Patients who receive a dose of esketamine should not drive or engage in other activities requiring alertness until the next day after a restful sleep. (Major) Concomitant use of opioid agonists with esketamine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with esketamine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Patients who have received a dose of esketamine should be instructed not to drive or engage in other activities requiring complete mental alertness until the next day after a restful sleep. Educate patients about the risks and symptoms of excessive CNS depression.
Eslicarbazepine: (Moderate) Concomitant use of codeine with eslicarbazepine can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If eslicarbazepine is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Eslicarbazepine is a moderate CYP3A4 inducer. (Minor) Eslicarbazepine may inhibit the CYP2C19-mediated metabolism of carisoprodol resulting in increased concentrations of carisoprodol. Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. The formation of meprobamate (active metabolite of carisoprodol) is catalyzed by CYP2C19. CYP2C19 inhibitors such as eslicarbazepine could increase carisoprodol plasma concentrations and decrease meprobamate concentrations, with potential for enhanced CNS depressant effects. The full pharmacological impact of these potential alterations of exposures in terms of either efficacy or safety of carisoprodol is unknown.
Esomeprazole: (Minor) Esomeprazole may inhibit the CYP2C19 isoenzyme, leading to increased plasma levels of drugs that are substrates for the CYP2C19 isoenzyme, such as carisoprodol. Carisoprdol is metabolized in the liver by CYP2C19 to form meprobamate. Coadministration may result in increased exposure to carisoprdol and decreased exposure of meprobamate.
Estazolam: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Moderate) Concomitant use of skeletal muscle relaxants with benzodiazepines can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take benzodiazepines with another CNS depressant for symptoms of excess sedation.
Eszopiclone: (Major) Concomitant use of opioid agonists with eszopiclone may cause excessive sedation, somnolence, and complex sleep-related behaviors (e.g., driving, talking, eating, or performing other activities while not fully awake). Avoid prescribing opioid cough medications in patients taking eszopiclone Limit the use of opioid pain medications with eszopiclone to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Instruct patients to contact their provider immediately if sleep-related symptoms or behaviors occur. Educate patients about the risks and symptoms of excessive CNS depression. (Moderate) Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants.
Ethacrynic Acid: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a loop diuretic and codeine; increase the dosage of the loop diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. (Moderate) Salicylates may decrease the diuretic, natriuretic, and antihypertensive actions of diuretics, possibly through inhibition of renal prostaglandin synthesis. Patients receiving loop diuretics and salicylates should be monitored for changes in the effectiveness of their diuretic therapy.
Ethanol: (Major) Advise patients to avoid alcohol consumption while taking CNS depressants. Alcohol consumption may result in additive CNS depression. (Major) Advise patients to avoid alcohol consumption while taking opioids. Alcohol consumption may result in additive CNS depression and may increase the risk for opioid overdose. Consider the patient's use of alcohol when prescribing opioid medications. If the patient is unlikely to be compliant with avoiding alcohol, consider prescribing naloxone especially if additional risk factors for opioid overdose are present. (Major) Concomitant ingestion of alcohol with salicylates, especially aspirin, ASA, increases the risk of developing gastric irritation and GI mucosal bleeding. Alcohol and salicylates are mucosal irritants and aspirin decreases platelet aggregation. Routine ingestion of alcohol and aspirin can cause significant GI bleeding, which may or may not be overt. Even occasional concomitant use of salicylates and alcohol should be avoided. Chronic ingestion of alcohol is often associated with hypoprothrombinemia and this condition increases the risk of salicylate-induced bleeding. Patients should be warned regarding the potential for increased risk of GI bleeding if alcohol-containing beverages are taken concurrently with salicylates.
Ethotoin: (Moderate) Additive CNS depression could be seen with the combined use of the hydantoin and opiate agonists. (Minor) Large doses of salicylates can displace hydantoins from plasma protein-binding sites. Although increased serum concentrations of unbound phenytoin may lead to phenytoin toxicity, the liver may also more rapidly clear unbound drug.
Etidronate: (Minor) Monitor for gastrointestinal adverse events during concurrent use of etidronate and aspirin. Both medications have been associated with gastrointestinal irritation although data suggest concomitant use introduces little additional risk for adverse effects for most patients.
Etodolac: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
Etomidate: (Major) Concomitant use of codeine with a general anesthetic may cause respiratory depression, hypotension, profound sedation, and death. Avoid prescribing opioid cough medications in patients receiving a general anesthetic. Limit the use of opioid pain medications with a general anesthetic to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation.
Etravirine: (Moderate) Concomitant use of codeine with etravirine can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If etravirine is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Etravirine is a moderate CYP3A4 inducer.
Everolimus: (Moderate) Monitor for signs and symptoms of respiratory depression or sedation and analgesic response if coadministration of codeine and everolimus is necessary, particularly if everolimus is added after a stable dose of codeine is achieved. If concurrent use is necessary, use the lowest effective dose of codeine and carefully titrate to desired clinical effect. Educate patients about the risks and symptoms of respiratory depression and sedation. Codeine is a substrate of CYP3A4 and CYP2D6; everolimus is a weak CYP3A4 inhibitor and CYP2D6 inhibitor. Concurrent use of a CYP3A4 inhibitor may shift codeine metabolism away from the CYP3A4 pathway such that more codeine is metabolized by CYP2D6, resulting in a higher rate of conversion to morphine and subsequent adverse events including respiratory depression, hypotension, profound sedation, and death. Discontinuation of a CYP3A4 inhibitor in a patient stabilized on codeine may decrease opioid efficacy and lead to withdrawal symptoms. Alternatively, CYP2D6 inhibitors can increase the plasma concentration of codeine, but decrease exposure to morphine resulting in decreased analgesia or opioid withdrawal. Discontinuation of a CYP2D6 inhibitor results in decreased codeine concentrations as the effect of the inhibitor declines but increased morphine plasma concentrations which may result in increased or prolonged opioid-related adverse reactions and potentially fatal respiratory depression.
Fedratinib: (Moderate) Concomitant use of codeine with fedratinib may alter codeine plasma concentrations, resulting in an unpredictable effect such as reduced efficacy or symptoms of opioid withdrawal or prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage adjustment of codeine until stable drug effects are achieved. If fedratinib is discontinued, monitor the patient carefully and consider adjusting the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Fedratinib is a moderate inhibitor of CYP3A4 and CYP2D6. CYP3A4 inhibitors may increase codeine-related adverse effects while CYP2D6 inhibitors may reduce efficacy. (Moderate) Monitor for an altered clinical response to carisoprodol if coadministration with fedratinib is necessary. Carisoprodol is metabolized by CYP2C19 to form meprobamate. Fedratinib is a moderate CYP2C19 inhibitor. Coadministration could increase exposure to carisoprodol and decrease exposure to meprobamate. The full pharmacological impact of these potential alterations of exposures in terms of either efficacy or safety of carisoprodol is unknown.
Felbamate: (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as felbamate, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
Fenfluramine: (Moderate) Concomitant use of opioid agonists with fenfluramine may cause excessive sedation and somnolence. Limit the use of opioid agonists with fenfluramine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Avoid prescribing opioid cough medication in patients taking fenfluramine. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Monitor for excessive sedation and somnolence during coadministration of fenfluramine and carisoprodol. Concurrent use may result in additive CNS depression.
Fenofibric Acid: (Minor) At therapeutic concentrations, fenofibric acid is a weak inhibitor of CYP2C19. Concomitant use of fenofibric acid with CYP2C19 substrates, such as carisoprodol, has not been formally studied. Fenofibric acid may theoretically increase plasma concentrations of CYP2C19 substrates and could lead to toxicity for drugs that have a narrow therapeutic range. Monitor the therapeutic effect of carisoprodol during coadministration with fenofibric acid.
Fenoprofen: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
Fentanyl: (Major) Concomitant use of fentanyl with carisoprodol may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation.
Fesoterodine: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when fesoterodine, an anticholinergic drug for overactive bladder is used with opiate agonists. The concomitant use of these drugs together may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Opiates increase the tone and decrease the propulsive contractions of the smooth muscle of the gastrointestinal tract. Prolongation of the gastrointestinal transit time may be the mechanism of the constipating effect. Both agents may also cause drowsiness or blurred vision, and patients should use care in driving or performing other hazardous tasks until the effects of the drugs are known.
Fish Oil, Omega-3 Fatty Acids (Dietary Supplements): (Moderate) Because fish oil, omega-3 fatty acids inhibit platelet aggregation, caution is advised when fish oils are used concurrently with aspirin. Theoretically, the risk of bleeding may be increased.
Flavocoxid, Flavocoxid; Citrated Zinc Bisglycinate: (Major) Because flavocoxid has been associated with isolated cases of occult GI bleeding, additive pharmacodynamic effects may be seen in patients receiving salicylates. Avoid the concurrent use of flavocoxid with salicylates until further data are available.
Flavoxate: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and flavoxate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Flibanserin: (Moderate) Concomitant use of opioid agonists with flibanserin may cause excessive sedation and somnolence. Limit the use of opioid pain medication with flibanserin to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Fluconazole: (Moderate) Concomitant use of codeine with fluconazole may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of fluconazole could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If fluconazole is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Fluconazole is a moderate inhibitor of CYP3A4.
Fluoxetine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and fluoxetine because of the potential risk of serotonin syndrome, reduced codeine efficacy, and potential for opioid withdrawal symptoms. Discontinue codeine if serotonin syndrome is suspected. It is recommended to avoid this combination when codeine is being used for cough. Concomitant use may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of fluoxetine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If fluoxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Fluoxetine is a strong inhibitor of CYP2D6. (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation. (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as fluoxetine, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
Fluphenazine: (Moderate) Concomitant use of opioid agonists with fluphenazine may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking fluphenazine. Limit the use of opioid pain medications with fluphenazine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. (Moderate) Phenothiazines can potentiate the CNS-depressant action of other drugs such as skeletal muscle relaxants. Caution should be exercised during simultaneous use of these agents due to potential for additive hypotension and excessive CNS effects (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Flurazepam: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Moderate) Concomitant use of skeletal muscle relaxants with benzodiazepines can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take benzodiazepines with another CNS depressant for symptoms of excess sedation.
Flurbiprofen: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
Fluvoxamine: (Major) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and fluvoxamine because of the potential risk of serotonin syndrome and prolonged opioid adverse reactions. Discontinue codeine if serotonin syndrome is suspected. It is recommended to avoid this combination when codeine is being used for cough. Concomitant use of codeine with fluvoxamine may increase codeine plasma concentrations and prolong opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of fluvoxamine could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If fluvoxamine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Fluvoxamine is a moderate inhibitor of CYP3A4. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation. (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as fluvoxamine, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
Fondaparinux: (Moderate) An additive risk of bleeding may be seen in patients receiving platelet inhibitors (e.g., aspirin, ASA) in combination with fondaparinux. Data on the concomitant use of fondaparinux with aspirin are lacking; however, large doses of salicylates (>= 3-4 g/day) can cause hypoprothrombinemia, an additional risk factor for bleeding.
Food: (Major) Advise patients to avoid cannabis use while taking CNS depressants due to the risk for additive CNS depression and potential for other cognitive adverse reactions.
Fosamprenavir: (Moderate) Concomitant use of codeine with fosamprenavir may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of fosamprenavir could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If fosamprenavir is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Fosamprenavir is a moderate inhibitor of CYP3A4.
Foscarnet: (Minor) Due to the inhibition of renal prostaglandins by salicylates, concurrent use of salicylates and other nephrotoxic agents, such as foscarnet, may lead to additive nephrotoxicity.
Fosinopril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
Fosinopril; Hydrochlorothiazide, HCTZ: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Fosphenytoin: (Moderate) Concomitant use of codeine with fosphenytoin can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If fosphenytoin is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Phenytoin, the active metabolite of fosphenytoin, is a strong CYP3A4 inducer. (Minor) Carisoprodol is metabolized by CYP2C19 to form meprobamate. Inducers of CYP2C19 like fosphenytoin could result in decreased exposure of carisoprodol and increased exposure of meprobamate. The clinical significance of these potential alterations of carisoprodol exposure is unknown. (Minor) Large doses of salicylates can displace phenytoin from plasma protein-binding sites. Although increased serum concentrations of unbound phenytoin may lead to phenytoin toxicity, the liver may also more rapidly clear unbound drug. Fosphenytoin is converted to phenytoin in vivo, so this interaction may also occur with fosphenytoin.
Fostamatinib: (Moderate) Monitor for codeine toxicities that may require codeine dose reduction if given concurrently with fostamatinib. Concomitant use of fostamatinib with a CYP3A4 substrate may increase the concentration of the CYP3A4 substrate. The active metabolite of fostamatinib, R406, is a CYP3A4 inhibitor; codeine is a substrate for CYP3A4. Coadministration of fostamatinib with a sensitive CYP3A4 substrate increased the substrate AUC by 64% and Cmax by 113%.
Frovatriptan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor agonists. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Furosemide: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a loop diuretic and codeine; increase the dosage of the loop diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. (Moderate) Salicylates may decrease the diuretic, natriuretic, and antihypertensive actions of diuretics, possibly through inhibition of renal prostaglandin synthesis. Patients receiving loop diuretics and salicylates should be monitored for changes in the effectiveness of their diuretic therapy.
Gabapentin: (Major) Concomitant use of opioid agonists with gabapentin may cause excessive sedation, somnolence, and respiratory depression. Avoid prescribing opioid cough medications in patients taking gabapentin. Limit the use of opioid pain medications with gabapentin to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, initiate gabapentin at the lowest recommended dose and monitor patients for symptoms of respiratory depression and sedation. Use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression and respiratory depression. (Major) Initiate gabapentin at the lowest recommended dose and monitor patients for symptoms of sedation and somnolence during coadministration of gabapentin and carisoprodol. Concomitant use of gabapentin with carisoprodol may cause additive CNS depression. Educate patients about the risks and symptoms of excessive CNS depression.
Garlic, Allium sativum: (Moderate) Garlic, Allium sativum may produce clinically-significant antiplatelet effects; until more data are available, garlic should be used cautiously in patients receiving drugs with a potential risk for bleeding such as aspirin, ASA.
General anesthetics: (Major) Concomitant use of codeine with a general anesthetic may cause respiratory depression, hypotension, profound sedation, and death. Avoid prescribing opioid cough medications in patients receiving a general anesthetic. Limit the use of opioid pain medications with a general anesthetic to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. (Moderate) General anesthetics potentiate the effect of other CNS depressants including carisoprodol.
Ginger, Zingiber officinale: (Moderate) There may be an increased risk of bleeding in patients on aspirin therapy who take ginger as a supplement (i.e., usual dietary intake is not expected to pose a risk). Several pungent constituents of ginger, Zingiber officinale are reported to inhibit arachidonic acid induced platelet activation in human whole blood. Ginger-associated platelet inhibition may be related to a decrease in COX-1/Thromboxane synthase enzymatic activity. The increas ed risk of bleeding is theoretical; clinical data of an interaction are not available.
Ginkgo, Ginkgo biloba: (Moderate) Monitor for signs or symptoms of bleeding with coadministration of ginkgo biloba and aspirin as an increased bleeding risk may occur. Although data are mixed, ginkgo biloba is reported to inhibit platelet aggregation and several case reports describe bleeding complications with ginkgo biloba, with or without concomitant drug therapy.
Givosiran: (Major) Avoid concomitant use of givosiran and codeine due to the risk of increased codeine plasma concentrations, but decreased plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of givosiran could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If givosiran is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Givosiran may moderately reduce hepatic CYP2D6 enzyme activity because of its pharmacological effects on the hepatic heme biosynthesis pathway.
Glimepiride: (Moderate) Monitor blood glucose during concomitant sulfonylurea and aspirin use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Glipizide: (Moderate) Monitor blood glucose during concomitant sulfonylurea and aspirin use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Glipizide; Metformin: (Moderate) Monitor blood glucose during concomitant metformin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant sulfonylurea and aspirin use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Glyburide: (Moderate) Monitor blood glucose during concomitant sulfonylurea and aspirin use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Glyburide; Metformin: (Moderate) Monitor blood glucose during concomitant metformin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant sulfonylurea and aspirin use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Glycerol Phenylbutyrate: (Moderate) Monitor for reduced efficacy of codeine and signs of opioid withdrawal in patients who have developed physical dependence if coadministration with glycerol phenylbutyrate is necessary; consider increasing the dose of codeine as needed. It is recommended to avoid this combination when codeine is being used for cough. If glycerol phenylbutyrate is discontinued, consider a dose reduction of codeine and frequently monitor for signs of respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Glycerol phenylbutyrate is a weak CYP3A inducer. Concomitant use with glycerol phenylbutyrate can increase norcodeine levels via increased CYP3A metabolism, resulting in decreased metabolism via CYP2D6 resulting in lower morphine levels; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence.
Glycopyrrolate: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and glycopyrrolate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Glycopyrrolate; Formoterol: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and glycopyrrolate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Granisetron: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Grapefruit juice: (Moderate) Patients should not significantly alter their intake of grapefruit or grapefruit juice during therapy with codeine. Grapefruit juice, a CYP3A4 inhibitor, may increase plasma concentrations of codeine, a CYP3A4 substrate. This may increase or prolong codeine-related toxicities including respiratory depression. Advise patients accordingly; patient monitoring and dosage adjustments may be necessary if grapefruit is consumed regularly.
Green Tea: (Moderate) Green tea should be used cautiously in patients taking aspirin; there may be an increased risk of bleeding. Monitoring clinical and/or laboratory parameters is warranted. Green tea has demonstrated antiplatelet and fibrinolytic actions in animals.
Griseofulvin: (Moderate) Concurrent administration of griseofulvin with salicylates may result in decreased salicylate serum concentrations. Caution and close monitoring for changes in the effectiveness of the salicylate are recommended.
Guaifenesin; Hydrocodone: (Major) Concomitant use of hydrocodone with other CNS depressants may lead to hypotension, profound sedation, coma, respiratory depression and death. Prior to concurrent use of hydrocodone in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. Hydrocodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate hydrocodone at 20 to 30% of the usual dosage in patients that are concurrently receiving another CNS depressant. Also consider a using a lower dose of the CNS depressant. Monitor patients for sedation and respiratory depression. (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking carisoprodol.
Guanfacine: (Moderate) Concomitant use of opioid agonists with guanfacine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with guanfacine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Guselkumab: (Moderate) Clinically relevant drug interactions may occur when guselkumab is administered with sensitive substrates of CYP2D6, such as codeine. Monitor for altered patient response to codeine; codeine dosage adjustments may be needed. During chronic inflammation, increased levels of certain cytokines can alter the formation of CYP450 enzymes. Thus, the formation of CYP2D6 could be normalized during guselkumab administration.
Haloperidol: (Moderate) Concomitant use of codeine with haloperidol may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of haloperidol could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If haloperidol is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Haloperidol is a moderate inhibitor of CYP2D6.
Heparin: (Moderate) An additive risk of bleeding may be seen in patients receiving platelet inhibitors (e.g., aspirin, ASA). Despite the potential drug-drug interaction between aspirin and heparin, heparin is frequently administered in combination with low-dose aspirin therapy to patients who have had an acute myocardial infarction and in other disease states. In addition, large doses of salicylates (>= 3-4 g/day) can cause hypoprothrombinemia, an additional risk factor for bleeding.
Homatropine; Hydrocodone: (Major) Concomitant use of hydrocodone with other CNS depressants may lead to hypotension, profound sedation, coma, respiratory depression and death. Prior to concurrent use of hydrocodone in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. Hydrocodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate hydrocodone at 20 to 30% of the usual dosage in patients that are concurrently receiving another CNS depressant. Also consider a using a lower dose of the CNS depressant. Monitor patients for sedation and respiratory depression. (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking carisoprodol. (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and homatropine use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Hyaluronidase, Recombinant; Immune Globulin: (Moderate) Immune Globulin (IG) products have been reported to be associated with renal dysfunction, acute renal failure, osmotic nephrosis, and death. Patients predisposed to acute renal failure include patients receiving known nephrotoxic drugs like nonsteroidal anti-inflammatory drugs (NSAIDs) and salicylates. Coadminister IG products at the minimum concentration available and the minimum rate of infusion practicable. Also, closely monitor renal function. (Minor) Salicylates, when given in large systemic doses, may render tissues partially resistant to the action of hyaluronidase. Patients receiving these medications may require larger amounts of hyaluronidase for equivalent dispersing effect.
Hyaluronidase: (Minor) Salicylates, when given in large systemic doses, may render tissues partially resistant to the action of hyaluronidase. Patients receiving these medications may require larger amounts of hyaluronidase for equivalent dispersing effect.
Hydrochlorothiazide, HCTZ: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Hydrochlorothiazide, HCTZ; Methyldopa: (Moderate) Concomitant use of opioid agonists with methyldopa may cause excessive sedation and somnolence. Limit the use of opioid pain medication with methyldopa to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Hydrochlorothiazide, HCTZ; Moexipril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Hydrocodone: (Major) Concomitant use of hydrocodone with other CNS depressants may lead to hypotension, profound sedation, coma, respiratory depression and death. Prior to concurrent use of hydrocodone in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. Hydrocodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate hydrocodone at 20 to 30% of the usual dosage in patients that are concurrently receiving another CNS depressant. Also consider a using a lower dose of the CNS depressant. Monitor patients for sedation and respiratory depression. (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking carisoprodol.
Hydrocodone; Ibuprofen: (Major) Concomitant use of analgesic doses of aspirin and ibuprofen is generally not recommended due to the increased risk of bleeding and renal impairment. Because there may be an increased risk of cardiovascular events due to the interference of ibuprofen with the antiplatelet effect of aspirin, for patients taking low-dose aspirin for cardioprotection who require analgesics, consider use of an NSAID that does not interfere with the antiplatelet effect of aspirin, or non-NSAID analgesics, as appropriate. Administer single doses of ibuprofen at least 2 to 4 hours or more after aspirin and wait 8 hours after ibuprofen administration before administering aspirin to avoid significant interference. Monitor for signs and symptoms of renal impairment. Pharmacodynamic studies have demonstrated interference with the antiplatelet activity of aspirin when ibuprofen 400 mg 3 times daily is administered with enteric-coated low-dose aspirin. The interaction exists even after ibuprofen 400 mg once daily, particularly when ibuprofen is dosed prior to aspirin. The interaction is alleviated if immediate-release low-dose aspirin is dosed at least 2 hours prior to a once daily regimen of ibuprofen; however, this finding cannot be extended to enteric-coated low-dose aspirin. A decrease in antiplatelet activity (53%) was observed when ibuprofen 400 mg once daily was administered 2 hours before low-dose immediate-release aspirin 81 mg/day for 6 days. An interaction was still observed, but minimized, when ibuprofen 400 mg once daily was administered as early as 8 hours before immediate-release aspirin (90.7%). There was no interaction with the antiplatelet activity of aspirin when ibuprofen 400 mg once daily was administered 2 hours after immediate-release aspirin (99.2%). In another study of low-dose immediate-release aspirin 81 mg/day and ibuprofen 400 mg 3 times daily (1, 7, and 13 hours post-aspirin dose) for 10 consecutive days, there was no interaction with the antiplatelet activity of aspirin (98.3%); however, there were individuals with aspirin antiplatelet activity below 95%, with the lowest being 90.2%. When a similarly designed study was conducted with enteric-coated aspirin 81 mg/day for 6 days and ibuprofen 400 mg 3 times daily (2, 7 and 12 h post-aspirin dose) for 6 days, there was an interaction with the antiplatelet activity at 24 hours after the day 6 aspirin dose (67%). Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone. Ibuprofen is not a substitute for low dose aspirin for cardiovascular protection. (Major) Concomitant use of hydrocodone with other CNS depressants may lead to hypotension, profound sedation, coma, respiratory depression and death. Prior to concurrent use of hydrocodone in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. Hydrocodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate hydrocodone at 20 to 30% of the usual dosage in patients that are concurrently receiving another CNS depressant. Also consider a using a lower dose of the CNS depressant. Monitor patients for sedation and respiratory depression. (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking carisoprodol.
Hydrocodone; Pseudoephedrine: (Major) Concomitant use of hydrocodone with other CNS depressants may lead to hypotension, profound sedation, coma, respiratory depression and death. Prior to concurrent use of hydrocodone in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. Hydrocodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate hydrocodone at 20 to 30% of the usual dosage in patients that are concurrently receiving another CNS depressant. Also consider a using a lower dose of the CNS depressant. Monitor patients for sedation and respiratory depression. (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking carisoprodol.
Hydromorphone: (Major) Concomitant use of hydromorphone with other central nervous system (CNS) depressants, such as other opiate agonists, can potentiate the effects of hydromorphone and may lead to additive CNS or respiratory depression, profound sedation, or coma. Prior to concurrent use of hydromorphone in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. If hydromorphone is used concurrently with a CNS depressant, a reduced dosage of hydromorphone and/or the CNS depressant is recommended; start with one-third to one-half of the estimated hydromorphone starting dose when using hydromorphone extended-release tablets. Carefully monitor the patient for hypotension, CNS depression, and respiratory depression. Carbon dioxide retention from opioid-induced respiratory depression can exacerbate the sedating effects of opioids. (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations.
Hydroxyzine: (Major) Concomitant use of opioid agonists with hydroxyzine may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking hydroxyzine. Limit the use of opioid pain medications with hydroxyzine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant.
Hyoscyamine: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and hyoscyamine use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate; Sodium Biphosphate: (Contraindicated) Codeine use in patients taking methylene blue or within 14 days of stopping such treatment is contraindicated due to the risk of serotonin syndrome or opioid toxicity. If urgent use of an opioid is necessary, use test doses and frequent titration of small doses of another opioid to treat pain while closely monitoring blood pressure and signs and symptoms of CNS and respiratory depression. (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and hyoscyamine use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Ibandronate: (Moderate) Monitor renal function and for gastrointestinal adverse events during concurrent use of intravenous or oral ibandronate use, respectively, and aspirin. Acute renal failure has been observed with intravenous ibandronate and concomitant use of other nephrotoxic agents may increase this risk. Additionally, the oral formulations of both medications have been associated with gastrointestinal irritation although data suggest concomitant use introduces little additional risk for adverse effects for most patients.
Ibritumomab Tiuxetan: (Major) During and after therapy, avoid the concomitant use of Yttrium (Y)-90 ibrutumomab tiuxetan with drugs that interfere with platelet function such as aspirin; the risk of bleeding may be increased. If coadministration with asprin is necessary, monitor platelet counts more frequently for evidence of thrombocytopenia. (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels. (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid.
Ibrutinib: (Moderate) The concomitant use of ibrutinib and antiplatelet agents such as aspirin may increase the risk of bleeding; monitor patients for signs of bleeding. Severe bleeding events have occurred with ibrutinib therapy including intracranial hemorrhage, GI bleeding, hematuria, and post procedural hemorrhage; some events were fatal. The mechanism for bleeding with ibrutinib therapy is not well understood. Also, aspirin may mask signs of infection such as fever and in patients following treatment with antineoplastic agents or immunosuppressives.
Ibuprofen: (Major) Concomitant use of analgesic doses of aspirin and ibuprofen is generally not recommended due to the increased risk of bleeding and renal impairment. Because there may be an increased risk of cardiovascular events due to the interference of ibuprofen with the antiplatelet effect of aspirin, for patients taking low-dose aspirin for cardioprotection who require analgesics, consider use of an NSAID that does not interfere with the antiplatelet effect of aspirin, or non-NSAID analgesics, as appropriate. Administer single doses of ibuprofen at least 2 to 4 hours or more after aspirin and wait 8 hours after ibuprofen administration before administering aspirin to avoid significant interference. Monitor for signs and symptoms of renal impairment. Pharmacodynamic studies have demonstrated interference with the antiplatelet activity of aspirin when ibuprofen 400 mg 3 times daily is administered with enteric-coated low-dose aspirin. The interaction exists even after ibuprofen 400 mg once daily, particularly when ibuprofen is dosed prior to aspirin. The interaction is alleviated if immediate-release low-dose aspirin is dosed at least 2 hours prior to a once daily regimen of ibuprofen; however, this finding cannot be extended to enteric-coated low-dose aspirin. A decrease in antiplatelet activity (53%) was observed when ibuprofen 400 mg once daily was administered 2 hours before low-dose immediate-release aspirin 81 mg/day for 6 days. An interaction was still observed, but minimized, when ibuprofen 400 mg once daily was administered as early as 8 hours before immediate-release aspirin (90.7%). There was no interaction with the antiplatelet activity of aspirin when ibuprofen 400 mg once daily was administered 2 hours after immediate-release aspirin (99.2%). In another study of low-dose immediate-release aspirin 81 mg/day and ibuprofen 400 mg 3 times daily (1, 7, and 13 hours post-aspirin dose) for 10 consecutive days, there was no interaction with the antiplatelet activity of aspirin (98.3%); however, there were individuals with aspirin antiplatelet activity below 95%, with the lowest being 90.2%. When a similarly designed study was conducted with enteric-coated aspirin 81 mg/day for 6 days and ibuprofen 400 mg 3 times daily (2, 7 and 12 h post-aspirin dose) for 6 days, there was an interaction with the antiplatelet activity at 24 hours after the day 6 aspirin dose (67%). Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone. Ibuprofen is not a substitute for low dose aspirin for cardiovascular protection.
Ibuprofen; Famotidine: (Major) Concomitant use of analgesic doses of aspirin and ibuprofen is generally not recommended due to the increased risk of bleeding and renal impairment. Because there may be an increased risk of cardiovascular events due to the interference of ibuprofen with the antiplatelet effect of aspirin, for patients taking low-dose aspirin for cardioprotection who require analgesics, consider use of an NSAID that does not interfere with the antiplatelet effect of aspirin, or non-NSAID analgesics, as appropriate. Administer single doses of ibuprofen at least 2 to 4 hours or more after aspirin and wait 8 hours after ibuprofen administration before administering aspirin to avoid significant interference. Monitor for signs and symptoms of renal impairment. Pharmacodynamic studies have demonstrated interference with the antiplatelet activity of aspirin when ibuprofen 400 mg 3 times daily is administered with enteric-coated low-dose aspirin. The interaction exists even after ibuprofen 400 mg once daily, particularly when ibuprofen is dosed prior to aspirin. The interaction is alleviated if immediate-release low-dose aspirin is dosed at least 2 hours prior to a once daily regimen of ibuprofen; however, this finding cannot be extended to enteric-coated low-dose aspirin. A decrease in antiplatelet activity (53%) was observed when ibuprofen 400 mg once daily was administered 2 hours before low-dose immediate-release aspirin 81 mg/day for 6 days. An interaction was still observed, but minimized, when ibuprofen 400 mg once daily was administered as early as 8 hours before immediate-release aspirin (90.7%). There was no interaction with the antiplatelet activity of aspirin when ibuprofen 400 mg once daily was administered 2 hours after immediate-release aspirin (99.2%). In another study of low-dose immediate-release aspirin 81 mg/day and ibuprofen 400 mg 3 times daily (1, 7, and 13 hours post-aspirin dose) for 10 consecutive days, there was no interaction with the antiplatelet activity of aspirin (98.3%); however, there were individuals with aspirin antiplatelet activity below 95%, with the lowest being 90.2%. When a similarly designed study was conducted with enteric-coated aspirin 81 mg/day for 6 days and ibuprofen 400 mg 3 times daily (2, 7 and 12 h post-aspirin dose) for 6 days, there was an interaction with the antiplatelet activity at 24 hours after the day 6 aspirin dose (67%). Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone. Ibuprofen is not a substitute for low dose aspirin for cardiovascular protection.
Ibuprofen; Oxycodone: (Major) Concomitant use of analgesic doses of aspirin and ibuprofen is generally not recommended due to the increased risk of bleeding and renal impairment. Because there may be an increased risk of cardiovascular events due to the interference of ibuprofen with the antiplatelet effect of aspirin, for patients taking low-dose aspirin for cardioprotection who require analgesics, consider use of an NSAID that does not interfere with the antiplatelet effect of aspirin, or non-NSAID analgesics, as appropriate. Administer single doses of ibuprofen at least 2 to 4 hours or more after aspirin and wait 8 hours after ibuprofen administration before administering aspirin to avoid significant interference. Monitor for signs and symptoms of renal impairment. Pharmacodynamic studies have demonstrated interference with the antiplatelet activity of aspirin when ibuprofen 400 mg 3 times daily is administered with enteric-coated low-dose aspirin. The interaction exists even after ibuprofen 400 mg once daily, particularly when ibuprofen is dosed prior to aspirin. The interaction is alleviated if immediate-release low-dose aspirin is dosed at least 2 hours prior to a once daily regimen of ibuprofen; however, this finding cannot be extended to enteric-coated low-dose aspirin. A decrease in antiplatelet activity (53%) was observed when ibuprofen 400 mg once daily was administered 2 hours before low-dose immediate-release aspirin 81 mg/day for 6 days. An interaction was still observed, but minimized, when ibuprofen 400 mg once daily was administered as early as 8 hours before immediate-release aspirin (90.7%). There was no interaction with the antiplatelet activity of aspirin when ibuprofen 400 mg once daily was administered 2 hours after immediate-release aspirin (99.2%). In another study of low-dose immediate-release aspirin 81 mg/day and ibuprofen 400 mg 3 times daily (1, 7, and 13 hours post-aspirin dose) for 10 consecutive days, there was no interaction with the antiplatelet activity of aspirin (98.3%); however, there were individuals with aspirin antiplatelet activity below 95%, with the lowest being 90.2%. When a similarly designed study was conducted with enteric-coated aspirin 81 mg/day for 6 days and ibuprofen 400 mg 3 times daily (2, 7 and 12 h post-aspirin dose) for 6 days, there was an interaction with the antiplatelet activity at 24 hours after the day 6 aspirin dose (67%). Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone. Ibuprofen is not a substitute for low dose aspirin for cardiovascular protection. (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Reduce the initial oxycodone dosage by one-third to one-half when using the extended-release tablets. (Major) Concomitant use of oxycodone with other opiate agonists may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Prior to concurrent use of oxycodone in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. If a CNS depressant is used concurrently with oxycodone, a reduced dosage of oxycodone and/or the CNS depressant is recommended; use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor for sedation and respiratory depression.
Ibuprofen; Pseudoephedrine: (Major) Concomitant use of analgesic doses of aspirin and ibuprofen is generally not recommended due to the increased risk of bleeding and renal impairment. Because there may be an increased risk of cardiovascular events due to the interference of ibuprofen with the antiplatelet effect of aspirin, for patients taking low-dose aspirin for cardioprotection who require analgesics, consider use of an NSAID that does not interfere with the antiplatelet effect of aspirin, or non-NSAID analgesics, as appropriate. Administer single doses of ibuprofen at least 2 to 4 hours or more after aspirin and wait 8 hours after ibuprofen administration before administering aspirin to avoid significant interference. Monitor for signs and symptoms of renal impairment. Pharmacodynamic studies have demonstrated interference with the antiplatelet activity of aspirin when ibuprofen 400 mg 3 times daily is administered with enteric-coated low-dose aspirin. The interaction exists even after ibuprofen 400 mg once daily, particularly when ibuprofen is dosed prior to aspirin. The interaction is alleviated if immediate-release low-dose aspirin is dosed at least 2 hours prior to a once daily regimen of ibuprofen; however, this finding cannot be extended to enteric-coated low-dose aspirin. A decrease in antiplatelet activity (53%) was observed when ibuprofen 400 mg once daily was administered 2 hours before low-dose immediate-release aspirin 81 mg/day for 6 days. An interaction was still observed, but minimized, when ibuprofen 400 mg once daily was administered as early as 8 hours before immediate-release aspirin (90.7%). There was no interaction with the antiplatelet activity of aspirin when ibuprofen 400 mg once daily was administered 2 hours after immediate-release aspirin (99.2%). In another study of low-dose immediate-release aspirin 81 mg/day and ibuprofen 400 mg 3 times daily (1, 7, and 13 hours post-aspirin dose) for 10 consecutive days, there was no interaction with the antiplatelet activity of aspirin (98.3%); however, there were individuals with aspirin antiplatelet activity below 95%, with the lowest being 90.2%. When a similarly designed study was conducted with enteric-coated aspirin 81 mg/day for 6 days and ibuprofen 400 mg 3 times daily (2, 7 and 12 h post-aspirin dose) for 6 days, there was an interaction with the antiplatelet activity at 24 hours after the day 6 aspirin dose (67%). Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone. Ibuprofen is not a substitute for low dose aspirin for cardiovascular protection.
Idelalisib: (Moderate) Concomitant use of codeine with idelalisib may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of idelalisib could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If idelalisib is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Idelalisib is a strong inhibitor of CYP3A4.
Iloperidone: (Moderate) Concomitant use of iloperidone with other centrally-acting medications such as opiate agonists, may increase both the frequency and the intensity of adverse effects including drowsiness, sedation, and dizziness.
Iloprost: (Moderate) When used concurrently with platelet inhibitors, inhaled iloprost may increase the risk of bleeding.
Imatinib: (Moderate) Concomitant use of codeine with imatinib may alter codeine plasma concentrations, resulting in an unpredictable effect such as reduced efficacy or symptoms of opioid withdrawal or prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage adjustment of codeine until stable drug effects are achieved. Discontinuation of imatinib could alter codeine plasma concentrations, resulting in an unpredictable effect such as prolonged opioid adverse reactions or decreased opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If imatinib is discontinued, monitor the patient carefully and consider adjusting the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Imatinib is a moderate inhibitor of CYP3A4 and CYP2D6. CYP3A4 inhibitors may increase codeine-related adverse effects while CYP2D6 inhibitors may reduce efficacy.
Imipramine: (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Moderate) Concomitant use of carisoprodol with tricyclic antidepressants can result in additive CNS depression (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Immune Globulin IV, IVIG, IGIV: (Moderate) Immune Globulin (IG) products have been reported to be associated with renal dysfunction, acute renal failure, osmotic nephrosis, and death. Patients predisposed to acute renal failure include patients receiving known nephrotoxic drugs like nonsteroidal anti-inflammatory drugs (NSAIDs) and salicylates. Coadminister IG products at the minimum concentration available and the minimum rate of infusion practicable. Also, closely monitor renal function.
Incretin Mimetics: (Moderate) Monitor blood glucose during concomitant incretin mimetic and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Indacaterol; Glycopyrrolate: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and glycopyrrolate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Indapamide: (Moderate) Monitor for decreased diuretic efficacy and additive orthostatic hypotension when indapamide is administered with codeine. Adjustments to diuretic therapy may be needed in some patients. The efficacy of diuretics may be reduced due to opioid-induced release of antidiuretic hormone. (Moderate) Salicylates can increase the risk of renal toxicity in patients receiving diuretics because salicylates inhibit renal prostaglandin synthesis, which can lead to fluid retention and increased peripheral vascular resistance.
Indinavir: (Moderate) Concomitant use of codeine with indinavir may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of indinavir could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If indinavir is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Indinavir is a strong inhibitor of CYP3A4.
Indomethacin: (Major) The concurrent use of salicylates and indomethacin is not recommended. Combined use does not produce any greater therapeutic effect than indomethacin monotherapy. Also, a significantly greater incidence of gastrointestinal adverse effects with concurrent use has been observed. Because NSAIDs can cause GI bleeding, inhibit platelet aggregation, and prolong bleeding time, additive effects may be seen in patients receiving platelet inhibitors (e.g., aspirin), anticoagulants, or thrombolytic agents.
Inotersen: (Moderate) Use caution with concomitant use of inotersen and salicylates due to the risk of glomerulonephritis and nephrotoxicity as well as the potential risk of bleeding from thrombocytopenia. Consider discontinuation of salicylates in a patient taking inotersen with a platelet count of less than 50,000 per microliter.
Insulins: (Moderate) Monitor blood glucose during concomitant insulin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Intravenous Lipid Emulsions: (Moderate) Because fish oil, omega-3 fatty acids inhibit platelet aggregation, caution is advised when fish oils are used concurrently with aspirin. Theoretically, the risk of bleeding may be increased.
Irbesartan; Hydrochlorothiazide, HCTZ: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Iron Sucrose, Sucroferric Oxyhydroxide: (Moderate) Administer aspirin at least 1 hour before oral iron sucrose, sucroferric oxyhydroxide. Oral iron salts may reduce the bioavailability of aspirin, leading to decreased absorption.
Isavuconazonium: (Moderate) Concomitant use of codeine with isavuconazonium may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of isavuconazonium could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If isavuconazonium is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Isavuconazonium is a moderate inhibitor of CYP3A4.
Isocarboxazid: (Contraindicated) Codeine use is contraindicated in patients who are receiving or who have received monoamine oxidase inhibitors (MAOIs) within the previous 14 days due to a risk for serotonin syndrome or opioid toxicity, including respiratory depression. Concomitant use of codeine with other serotonergic drugs such as MAOIs may result in serious adverse effects including serotonin syndrome. MAOIs may cause additive CNS depression, respiratory depression, drowsiness, dizziness, or hypotension when used with opiate agonists such as codeine. If urgent use of an opioid is necessary, use test doses and frequent titration of small doses of alternate opioids to treat pain while closely monitoring blood pressure and signs and symptoms of CNS and respiratory depression.
Isoflurane: (Major) Concomitant use of codeine with a general anesthetic may cause respiratory depression, hypotension, profound sedation, and death. Avoid prescribing opioid cough medications in patients receiving a general anesthetic. Limit the use of opioid pain medications with a general anesthetic to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation.
Isoniazid, INH: (Moderate) Concomitant use of codeine with isoniazid may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of isoniazid could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If isoniazid is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Isoniazid is a weak inhibitor of CYP3A.
Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Moderate) Concomitant use of codeine with isoniazid may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of isoniazid could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If isoniazid is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Isoniazid is a weak inhibitor of CYP3A. (Moderate) Concomitant use of codeine with rifampin can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If rifampin is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Rifampin is a strong CYP3A4 inducer. (Minor) Carisoprodol is metabolized via CYP2C19. The formation of meprobamate (active metabolite of carisoprodol) is catalyzed by CYP2C19. If carisoprodol is combined with an inducer of CYP2C19 such as rifampin, the potential exists for increased metabolism of carisoprodol. Theoretically, carisoprodol plasma concentrations could be decreased, and meprobamate (active metabolite) plasma concentrations could be increased. The clinical significance of this interaction is unknown.
Isoniazid, INH; Rifampin: (Moderate) Concomitant use of codeine with isoniazid may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of isoniazid could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If isoniazid is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Isoniazid is a weak inhibitor of CYP3A. (Moderate) Concomitant use of codeine with rifampin can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If rifampin is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Rifampin is a strong CYP3A4 inducer. (Minor) Carisoprodol is metabolized via CYP2C19. The formation of meprobamate (active metabolite of carisoprodol) is catalyzed by CYP2C19. If carisoprodol is combined with an inducer of CYP2C19 such as rifampin, the potential exists for increased metabolism of carisoprodol. Theoretically, carisoprodol plasma concentrations could be decreased, and meprobamate (active metabolite) plasma concentrations could be increased. The clinical significance of this interaction is unknown.
Istradefylline: (Moderate) Concomitant use of codeine with istradefylline 40 mg daily may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of istradefylline could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If istradefylline is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Istradefylline administered as 40 mg daily is a weak CYP3A4 inhibitor; there was no effect on drug exposure when istradefylline 20 mg daily was coadministered with a sensitive CYP3A4 substrate.
Itraconazole: (Moderate) Concomitant use of codeine with itraconazole may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of itraconazole could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If itraconazole is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Itraconazole is a strong inhibitor of CYP3A4.
Ketamine: (Major) Concomitant use of codeine with a general anesthetic may cause respiratory depression, hypotension, profound sedation, and death. Avoid prescribing opioid cough medications in patients receiving a general anesthetic. Limit the use of opioid pain medications with a general anesthetic to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation.
Ketoconazole: (Moderate) Concomitant use of codeine with ketoconazole may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of ketoconazole could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If ketoconazole is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Ketoconazole is a strong inhibitor of CYP3A4.
Ketoprofen: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
Ketorolac: (Contraindicated) Ketorolac is contraindicated in patients currently receiving salicylates due to increased risk of serious NSAID-related adverse events, including gastrointestinal bleeding, ulceration, and perforation.
Lamivudine; Tenofovir Disoproxil Fumarate: (Major) Renal impairment, which may include hypophosphatemia, has been reported with the use of tenofovir disoproxil fumarate with a majority of the cases occurring in patients who have underlying systemic or renal disease or who are concurrently taking nephrotoxic agents. Tenofovir should be avoided with concurrent or recent use of a nephrotoxic agent; patients receiving concomitant nephrotoxic agents, like salicylates should be carefully monitored for changes in serum creatinine and phosphorus.
Lansoprazole; Amoxicillin; Clarithromycin: (Moderate) Concomitant use of codeine with clarithromycin may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of clarithromycin could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If clarithromycin is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Clarithromycin is a strong inhibitor of CYP3A4. (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Lapatinib: (Moderate) Concomitant use of codeine with lapatinib may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of lapatinib could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If lapatinib is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Lapatinib is a weak inhibitor of CYP3A4.
Larotrectinib: (Moderate) Concomitant use of codeine with larotrectinib may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6 and, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of larotrectinib could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If larotrectinib is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Larotrectinib is a weak inhibitor of CYP3A4.
Lasmiditan: (Moderate) Concomitant use of codeine with lasmiditan may cause excessive sedation, somnolence, and serotonin syndrome. Limit the use of codeine with lasmiditan to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression and serotonin syndrome. Avoid prescribing codeine cough medications in patients taking lasmiditan. (Moderate) Monitor for excessive sedation and somnolence during coadministration of lasmiditan and carisoprodol. Concurrent use may result in additive CNS depression.
Lefamulin: (Moderate) Concomitant use of codeine with oral lefamulin may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of oral lefamulin could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If oral lefamulin is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Oral lefamulin is a moderate CYP3A4 inhibitor; an interaction is not expected with intravenous lefamulin.
Lemborexant: (Moderate) Concomitant use of codeine with lemborexant may cause excessive sedation and somnolence. Limit the use of codeine with lemborexant to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. Avoid prescribing codeine cough medicine in patients taking lemborexant. (Moderate) Monitor for excessive sedation and somnolence during coadministration of lemborexant and carisoprodol. Dosage adjustments of lemborexant and carisoprodol may be necessary when administered together because of potentially additive CNS effects. The risk of next-day impairment, including impaired driving, is increased if lemborexant is taken with other CNS depressants.
Lenacapavir: (Moderate) Concomitant use of codeine with lenacapavir may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of lenacapavir could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If lenacapavir is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Lenacapavir is a moderate inhibitor of CYP3A.
Lesinurad: (Moderate) Aspirin, ASA at doses higher than 325 mg per day may decrease the efficacy of lesinurad in combination with allopurinol. Aspirin at doses of 325 mg or less per day (i.e., for cardiovascular protection) does not decrease the efficacy of lesinurad and can be coadministered with lesinurad.
Lesinurad; Allopurinol: (Moderate) Aspirin, ASA at doses higher than 325 mg per day may decrease the efficacy of lesinurad in combination with allopurinol. Aspirin at doses of 325 mg or less per day (i.e., for cardiovascular protection) does not decrease the efficacy of lesinurad and can be coadministered with lesinurad.
Letermovir: (Moderate) Concomitant use of codeine with letermovir may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of letermovir could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If letermovir is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Letermovir is a moderate inhibitor of CYP3A4.
Levamlodipine: (Moderate) Monitor for an increase in codeine-related adverse reactions including sedation and respiratory depression if coadministration with amlodipine is necessary; adjust the dose of codeine if necessary. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Amlodipine is a weak CYP3A4 inhibitor. Concomitant use may result in an increase in codeine plasma concentrations, resulting in greater metabolism by CYP2D6 and increased morphine concentrations.
Levocetirizine: (Major) Reserve concomitant use of opioids and cetirizine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Monitor for unusual drowsiness and sedation during coadministration of cetirizine and skeletal muscle relaxants due to the risk for additive CNS depression.
Levoketoconazole: (Moderate) Concomitant use of codeine with ketoconazole may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of ketoconazole could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If ketoconazole is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Ketoconazole is a strong inhibitor of CYP3A4.
Levomilnacipran: (Moderate) If concomitant use of codeine and levomilnacipran is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Levorphanol: (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Reduce the initial levorphanol dosage by 50% or more.
Lidocaine: (Moderate) The use of these drugs together must be approached with caution. Although commonly used together for additive analgesic effects, the patient must be monitored for respiratory depression, hypotension, and excessive sedation due to additive effects on the CNS and blood pressure. In rare instances, serious morbidity and mortality has occurred. Limit the use of opiate pain medications with local anesthetics to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. The use of the local anesthetic may allow for the use a lower initial dose of the opiate and then the doses can be titrated to proper clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
Lidocaine; Epinephrine: (Moderate) The use of these drugs together must be approached with caution. Although commonly used together for additive analgesic effects, the patient must be monitored for respiratory depression, hypotension, and excessive sedation due to additive effects on the CNS and blood pressure. In rare instances, serious morbidity and mortality has occurred. Limit the use of opiate pain medications with local anesthetics to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. The use of the local anesthetic may allow for the use a lower initial dose of the opiate and then the doses can be titrated to proper clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
Lidocaine; Prilocaine: (Moderate) The use of these drugs together must be approached with caution. Although commonly used together for additive analgesic effects, the patient must be monitored for respiratory depression, hypotension, and excessive sedation due to additive effects on the CNS and blood pressure. In rare instances, serious morbidity and mortality has occurred. Limit the use of opiate pain medications with local anesthetics to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. The use of the local anesthetic may allow for the use a lower initial dose of the opiate and then the doses can be titrated to proper clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
Linagliptin: (Moderate) Monitor blood glucose during concomitant linagliptin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Linagliptin; Metformin: (Moderate) Monitor blood glucose during concomitant linagliptin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant metformin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Linezolid: (Contraindicated) Codeine use in patients taking linezolid or within 14 days of stopping such treatment is contraindicated due to the risk of serotonin syndrome or opioid toxicity. If urgent use of an opioid is necessary, use test doses and frequent titration of small doses of another opioid to treat pain while closely monitoring blood pressure and signs and symptoms of CNS and respiratory depression.
Lisdexamfetamine: (Moderate) If concomitant use of codeine and amphetamines is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Lisinopril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
Lisinopril; Hydrochlorothiazide, HCTZ: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Lithium: (Moderate) If concomitant use of codeine and lithium is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Lofexidine: (Moderate) Monitor for excessive hypotension and sedation during coadministration of lofexidine and carisoprodol. Lofexidine can potentiate the effects of CNS depressants. (Moderate) Monitor for excessive hypotension and sedation during coadministration of lofexidine and codeine. Lofexidine can potentiate the effects of CNS depressants.
Lonafarnib: (Moderate) Concomitant use of codeine with lonafarnib may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6 and, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of lonafarnib could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If lonafarnib is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties; lonafarnib is a strong inhibitor of CYP3A4. (Moderate) Monitor for an altered clinical response to carisoprodol if coadministration with lonafarnib is necessary. Carisoprodol is metabolized by CYP2C19 to form meprobamate; lonafarnib is a moderate CYP2C19 inhibitor. Coadministration could increase exposure to carisoprodol and decrease exposure to meprobamate. The full pharmacological impact of these potential alterations of exposure in terms of either efficacy or safety of carisoprodol is unknown.
Loop diuretics: (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a loop diuretic and codeine; increase the dosage of the loop diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. (Moderate) Salicylates may decrease the diuretic, natriuretic, and antihypertensive actions of diuretics, possibly through inhibition of renal prostaglandin synthesis. Patients receiving loop diuretics and salicylates should be monitored for changes in the effectiveness of their diuretic therapy.
Lopinavir; Ritonavir: (Moderate) Concomitant use of codeine with ritonavir may alter codeine plasma concentrations, resulting in an unpredictable effect such as reduced efficacy or symptoms of opioid withdrawal or prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage adjustment of codeine until stable drug effects are achieved. Discontinuation of ritonavir could alter codeine plasma concentrations, resulting in an unpredictable effect such as prolonged opioid adverse reactions or decreased opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If ritonavir is discontinued, monitor the patient carefully and consider adjusting the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Ritonavir is a strong inhibitor of CYP3A4 and a weak inhibitor of CYP2D6. CYP3A4 inhibitors may increase codeine-related adverse effects while CYP2D6 inhibitors may reduce efficacy.
Lorazepam: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Moderate) Concomitant use of skeletal muscle relaxants with benzodiazepines can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take benzodiazepines with another CNS depressant for symptoms of excess sedation.
Lorcaserin: (Moderate) If concomitant use of codeine and lorcaserin is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Lorlatinib: (Moderate) Monitor for reduced efficacy of codeine and signs of opioid withdrawal in patients who have developed physical dependence if coadministration with lorlatinib is necessary; consider increasing the dose of codeine as needed. It is recommended to avoid this combination when codeine is being used for cough. If lorlatinib is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Lorlatinib is a moderate CYP3A4 inducer. Concomitant use with lorlatinib can increase norcodeine levels via increased CYP3A4 metabolism, resulting in decreased metabolism via CYP2D6 resulting in lower morphine levels; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence.
Losartan; Hydrochlorothiazide, HCTZ: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Low Molecular Weight Heparins: (Moderate) An additive risk of bleeding may be seen in patients receiving a low molecular weight heparin in combination with other agents known to increase the risk of bleeding such as salicylates. Monitor clinical and laboratory response closely during concurrent use.
Loxapine: (Moderate) Concomitant use of opioid agonists like codeine with loxapine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with loxapine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Avoid prescribing opioid cough medication in patients taking loxapine. (Moderate) Loxapine is a central nervous system (CNS) depressant. The concurrent use of loxapine with other CNS depressants (e.g., muscle relaxants such as carisprodol) can increase the risk of respiratory depression, hypotension, profound sedation, and syncope. Therefore, consider reducing the dose of CNS depressants if used concomitantly with loxapine.
Luliconazole: (Moderate) Theoretically, luliconazole may increase the side effects of carisoprodol, which is a CYP2C19 substrate. Monitor patients for adverse effects of carisoprodol, such as CNS depression. In vitro, therapeutic doses of luliconazole inhibit the activity of CYP2C19 and small systemic concentrations may be noted with topical application, particularly when applied to patients with moderate to severe tinea cruris. No in vivo drug interaction trials were conducted prior to the approval of luliconazole.
Lumacaftor; Ivacaftor: (Moderate) Concomitant use of codeine with lumacaftor; ivacaftor can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If lumacaftor; ivacaftor is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Lumacaftor; ivacaftor is a strong CYP3A4 inducer. (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. The formation of meprobamate (active metabolite of carisoprodol) is catalyzed by CYP2C19. In vitro data suggest that lumacaftor may induce CYP2C19. If these drugs are coadministered, the potential exists for increased metabolism of carisoprodol. Theoretically, carisoprodol plasma concentrations could be decreased, and meprobamate (active metabolite) plasma concentrations could be increased. The full pharmacological impact of these potential alterations of exposures in terms of either efficacy or safety of carisoprodol is unknown.
Lumateperone: (Moderate) Concomitant use of opioid agonists like codeine with lumateperone may cause excessive sedation and somnolence. Limit the use of opioid pain medication with lumateperone to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Avoid prescribing opioid cough medication in patients taking lumateperone. (Moderate) Monitor for excessive sedation and somnolence during coadministration of lumateperone and skeletal muscle relaxants. Concurrent use may result in additive CNS depression.
Lurasidone: (Moderate) Concomitant use of opioid agonists like codeine with lurasidone may cause excessive sedation and somnolence. Limit the use of opioid pain medication with lurasidone to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Avoid prescribing opioid cough medication in patients taking lurasidone.
Macimorelin: (Major) Avoid use of macimorelin with drugs that directly affect pituitary growth hormone secretion, such as salicylates. Healthcare providers are advised to discontinue salicylate therapy and observe a sufficient washout period before administering macimorelin. Use of these medications together may impact the accuracy of the macimorelin growth hormone test.
Mannitol: (Major) In general, avoid use of mannitol and salicylates. Concomitant administration of nephrotoxic drugs, such as the salicylates, increases the risk of renal failure after administration of mannitol. However, mannitol promotes the urinary excretion of salicylates, and may be used as an adjunct in salicylate intoxication.
Maprotiline: (Major) Concomitant use of opioid agonists with maprotiline may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking maprotiline. Limit the use of opioid pain medications with maprotiline to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. (Moderate) Skeletal muscle relaxants should be combined cautiously with cyclic antidepressants like maprotiline because they could cause additive CNS depressant effects. Depending on the specific agent (e.g., cyclobenzaprine, and orphenadrine), additive anticholinergic effects may also be seen. Clinicians should note that antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Patients should be monitored for excessive adverse effects from either agent.
Maribavir: (Moderate) Concomitant use of codeine with maribavir may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of maribavir could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If maribavir is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Maribavir is a weak CYP3A inhibitor.
Mavacamten: (Moderate) Monitor for an altered clinical response to carisoprodol if coadministration with mavacamten is necessary. Carisoprodol is metabolized by CYP2C19 to form meprobamate; mavacamten is a moderate CYP2C19 inducer. Coadministration could decrease exposure to carisoprodol and increase exposure to meprobamate. The full pharmacological impact of these potential alterations of exposure in terms of either efficacy or safety of carisoprodol is unknown. (Moderate) Monitor for reduced efficacy of codeine and signs of opioid withdrawal in patients who have developed physical dependence if coadministration with mavacamten is necessary; consider increasing the dose of codeine as needed. It is recommended to avoid this combination when codeine is being used for cough. If mavacamten is discontinued, consider a dose reduction of codeine and frequently monitor for signs of respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Mavacamten is a moderate CYP3A inducer. Concomitant use with mavacamten can increase norcodeine levels via increased CYP3A metabolism, resulting in decreased metabolism via CYP2D6 resulting in lower morphine levels; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence.
Measles Virus; Mumps Virus; Rubella Virus; Varicella Virus Vaccine, Live: (Major) No adverse events associated with the use of salicylates after varicella vaccination have been reported. However, the manufacturer of varicella virus vaccine live recommends the avoidance of salicylates or aspirin, ASA use for 6 weeks after vaccination. Reye's syndrome, which exclusively affects children under 15 years old, has been associated with aspirin use following active varicella infection. Vaccination with close clinical monitoring is recommended for children who require therapeutic aspirin, ASA therapy; according to the CDC the use of attenuated, live varicella virus vaccine is thought to present less risk than natural varicella disease to such children.
Meclizine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant.
Meclofenamate Sodium: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
Mefenamic Acid: (Major) Increased adverse gastrointestinal (GI) effects are possible if mefenamic acid is used with salicylates. In addition, concomitant administration of salicylates and mefenamic acid may result in an increase in unbound plasma concentrations of either drug, which could result in greater adverse effects. In general, concomitant use of aspirin and mefenamic acid is not recommended.
Meglitinides: (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of antidiabetic agents. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose or use of greater than maximum recommended daily dosages, salicylates can cause either hypoglycemia or hyperglycemia. Large doses of aspirin should be used cautiously in patients who receive antidiabetic agents.
Melatonin: (Moderate) Concomitant use of opioid agonists with melatonin may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking melatonin. Limit the use of opioid pain medications with melatonin to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression.
Meloxicam: (Major) Concomitant use of low dose aspirin or analgesic doses of aspirin and meloxicam is generally not recommended due to the increased risk of bleeding and renal impairment. Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone. Meloxicam is not a substitute for low dose aspirin for cardiovascular protection.
Meperidine: (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations.
Mepivacaine: (Moderate) The use of these drugs together must be approached with caution. Although commonly used together for additive analgesic effects, the patient must be monitored for respiratory depression, hypotension, and excessive sedation due to additive effects on the CNS and blood pressure. In rare instances, serious morbidity and mortality has occurred. Limit the use of opiate pain medications with local anesthetics to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. The use of the local anesthetic may allow for the use a lower initial dose of the opiate and then the doses can be titrated to proper clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
Meprobamate: (Major) Concomitant use of carisoprodol and meprobamate is not recommended. Meprobamate is an active metabolite of carisoprodol. (Moderate) Concomitant use of meprobamate with codeine can potentiate the effects of codeine, which may potentially lead to respiratory depression, CNS depression, sedation, or hypotensive responses. Prior to concurrent use, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. A reduced dosage of codeine and/or meprobamate may be recommended. Monitor patients for sedation and respiratory depression.
Metaxalone: (Major) Concomitant use of opioid agonists with metaxalone may cause respiratory depression, profound sedation, and death. Limit the use of opioid pain medication with metaxalone to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking metaxalone. Educate patients about the risks and symptoms of respiratory depression and sedation. Consider prescribing naloxone for the emergency treatment of opioid overdose. Concomitant use of metaxalone and opioid agonists increases the risk for serotonin syndrome. Avoid concomitant use if possible and monitor for serotonin syndrome if use is necessary.
Metformin: (Moderate) Monitor blood glucose during concomitant metformin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Metformin; Repaglinide: (Moderate) Monitor blood glucose during concomitant metformin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of antidiabetic agents. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose or use of greater than maximum recommended daily dosages, salicylates can cause either hypoglycemia or hyperglycemia. Large doses of aspirin should be used cautiously in patients who receive antidiabetic agents.
Metformin; Rosiglitazone: (Moderate) Monitor blood glucose during concomitant metformin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Metformin; Saxagliptin: (Moderate) Monitor blood glucose during concomitant metformin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant saxagliptin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Metformin; Sitagliptin: (Moderate) Monitor blood glucose during concomitant metformin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant sitagliptin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Methadone: (Major) Concomitant use of methadone with another CNS depressant can lead to additive respiratory depression, hypotension, profound sedation, or coma. Prior to concurrent use of methadone in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. Methadone should be used with caution and in reduced dosages if used concurrently with a CNS depressant; also consider a using a lower dose of the CNS depressant. Monitor patients for sedation and respiratory depression. (Major) Concomitant use of methadone with carisoprodol may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation.
Methamphetamine: (Moderate) If concomitant use of codeine and amphetamines is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Methazolamide: (Major) Avoid the coadministration of high-dose salicylates and carbonic anhydrase inhibitors, like methazolamide, whenever possible. The combination yielded reports of anorexia, tachypnea, lethargy, metabolic acidosis, coma, and death. The mechanism appears to be accumulation of the carbonic anhydrase inhibitor, resulting in increased CNS depression and metabolic acidosis. The acidosis may allow greater CNS penetration of the salicylate.
Methenamine; Sodium Acid Phosphate; Methylene Blue; Hyoscyamine: (Contraindicated) Codeine use in patients taking methylene blue or within 14 days of stopping such treatment is contraindicated due to the risk of serotonin syndrome or opioid toxicity. If urgent use of an opioid is necessary, use test doses and frequent titration of small doses of another opioid to treat pain while closely monitoring blood pressure and signs and symptoms of CNS and respiratory depression. (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and hyoscyamine use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Methocarbamol: (Major) Concomitant use of opioid agonists with methocarbamol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with methocarbamol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking methocarbamol.
Methohexital: (Major) Concomitant use of codeine with barbiturates may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with barbiturates to only patients for whom alternative treatment options are inadequate. It is recommended to avoid this combination when codeine is being used for cough. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Additionally, concomitant use of codeine with a barbiturate can decrease codeine concentrations, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. Monitor for reduced efficacy of codeine and signs of opioid withdrawal. Discontinuation of a barbiturate may increase the risk of opioid-related adverse reactions, such as fatal respiratory depression. Barbiturates induce CYP3A4. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. (Moderate) Concomitant use of skeletal muscle relaxants with barbiturates can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take barbiturates with another CNS depressant for symptoms of excess sedation.
Methotrexate: (Major) Do not administer salicylates before or concomitantly with high doses of methotrexate, such as used in the treatment of osteosarcoma. Concomitant administration of some NSAIDs with high dose methotrexate therapy has been reported to elevate and prolong serum methotrexate concentrations, resulting in deaths from severe hematologic and gastrointestinal toxicity. Use caution when salicylates are administered concomitantly with lower doses of methotrexate. Salicylates have been reported to reduce the tubular secretion of methotrexate in an animal model and may enhance its toxicity. Methotrexate is partially bound to serum albumin, and toxicity may be increased because of displacement by salicylates.
Methscopolamine: (Moderate) CNS depression can be increased when methscopolamine is combined with other CNS depressants such as skeletal muscle relaxants. (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and methscopolamine use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Methyclothiazide: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Methyldopa: (Moderate) Concomitant use of opioid agonists with methyldopa may cause excessive sedation and somnolence. Limit the use of opioid pain medication with methyldopa to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Methylene Blue: (Contraindicated) Codeine use in patients taking methylene blue or within 14 days of stopping such treatment is contraindicated due to the risk of serotonin syndrome or opioid toxicity. If urgent use of an opioid is necessary, use test doses and frequent titration of small doses of another opioid to treat pain while closely monitoring blood pressure and signs and symptoms of CNS and respiratory depression.
Methylphenidate Derivatives: (Moderate) If concomitant use of codeine and methylphenidate or its derivatives is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Methylsulfonylmethane, MSM: (Moderate) It would be prudent for patients who take aspirin to avoid methylsulfonylmethane, MSM. Monitor patients who choose to take MSM while on aspirin therapy for bleeding. Patients taking MSM and anticoagulant drugs have reported increased anticoagulant effects such as increased bruising or blood in the stool.
Metoclopramide: (Moderate) The effects of metoclopramide on gastrointestinal motility are antagonized by narcotic analgesics. Concomitant use of opioid agonists with metoclopramide may also cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking metoclopramide. Limit the use of opioid pain medications with metoclopramide to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. (Minor) Metoclopramide can increase the rate or extent of absorption of aspirin because of accelerated gastric emptying, which increases the contact time with the small bowel where this drug is absorbed.
Metolazone: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Metoprolol; Hydrochlorothiazide, HCTZ: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Metyrapone: (Moderate) Metyrapone may cause dizziness and/or drowsiness. Other drugs that may also cause drowsiness, such as carisoprodol, should be used with caution. Additive drowsiness and/or dizziness is possible.
Metyrosine: (Moderate) The concomitant administration of metyrosine with opiate agonists can result in additive sedative effects.
Midazolam: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Moderate) Concomitant use of skeletal muscle relaxants with benzodiazepines can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take benzodiazepines with another CNS depressant for symptoms of excess sedation.
Mifepristone: (Moderate) Concomitant use of codeine with chronic mifepristone therapy may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of mifepristone could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If mifepristone is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Mifepristone is a strong inhibitor of CYP3A4. The clinical significance of this interaction with the short-term use of mifepristone for termination of pregnancy is unknown.
Milnacipran: (Moderate) If concomitant use of codeine and milnacipran is warranted, monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Minocycline: (Minor) Injectable minocycline contains magnesium sulfate heptahydrate. Because of the CNS-depressant effects of magnesium sulfate, additive central-depressant effects can occur following concurrent administration with CNS depressants such as opiate agonists. Caution should be exercised when using these agents concurrently.
Mirabegron: (Moderate) Concomitant use of codeine with mirabegron may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of mirabegron could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If mirabegron is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Mirabegron is a moderate inhibitor of CYP2D6.
Mirtazapine: (Major) Concomitant use of opioid agonists with mirtazapine may cause excessive sedation and somnolence. Limit the use of opioid pain medications with mirtazapine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking mirtazapine. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. (Moderate) Skeletal muscle relaxants like carisoprodol may cause additive CNS depression if used concomitantly with other drugs with CNS depressant properties such as mirtazapine. Combination therapy may amplify sedation and dizziness, which can impair the patient's ability to perform tasks requiring mental alertness. Dosage adjustments of either or both medications may be necessary in some instances.
Mitapivat: (Moderate) Monitor for reduced efficacy of codeine and signs of opioid withdrawal in patients who have developed physical dependence if coadministration with mitapivat is necessary; consider increasing the dose of codeine as needed. It is recommended to avoid this combination when codeine is being used for cough. If mitapivat is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Mitapivat is a weak CYP3A inducer. Concomitant use with mitapivat can increase norcodeine levels via increased CYP3A metabolism, resulting in decreased metabolism via CYP2D6 resulting in lower morphine levels; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence.
Mitotane: (Moderate) Concomitant use of codeine with mitotane can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If mitotane is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Mitotane is a strong CYP3A4 inducer.
Mobocertinib: (Moderate) Monitor for reduced efficacy of codeine and signs of opioid withdrawal in patients who have developed physical dependence if coadministration with mobocertinib is necessary; consider increasing the dose of codeine as needed. It is recommended to avoid this combination when codeine is being used for cough. If mobocertinib is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Mobocertinib is a weak CYP3A inducer. Concomitant use with mobocertinib can increase norcodeine levels via increased CYP3A metabolism, resulting in decreased metabolism via CYP2D6 resulting in lower morphine levels; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence.
Modafinil: (Moderate) Concomitant use of codeine with modafinil can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If modafinil is discontinued, consider a dose reduction of codeine and frequently monitor for signs or resp iratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Modafinil is a moderate CYP3A4 inducer. (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as modafinil, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
Moexipril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
Molindone: (Moderate) Concomitant use of opioid agonists like codeine with molindone may cause excessive sedation and somnolence. Limit the use of opioid pain medication with molindone to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Avoid prescribing opioid cough medication in patients taking molindone. (Moderate) Simultaneous use of skeletal muscle relaxants and other CNS depressants, such as molindone, can increase CNS depression. In addition, antipsychotics are associated with anticholinergic effects; therefore, additive effects may be seen during concurrent use of molindone and other drugs having anticholinergic activity. Clinicians should note that antimuscarinic effects may be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation.
Monoamine oxidase inhibitors: (Contraindicated) Codeine use is contraindicated in patients who are receiving or who have received monoamine oxidase inhibitors (MAOIs) within the previous 14 days due to a risk for serotonin syndrome or opioid toxicity, including respiratory depression. Concomitant use of codeine with other serotonergic drugs such as MAOIs may result in serious adverse effects including serotonin syndrome. MAOIs may cause additive CNS depression, respiratory depression, drowsiness, dizziness, or hypotension when used with opiate agonists such as codeine. If urgent use of an opioid is necessary, use test doses and frequent titration of small doses of alternate opioids to treat pain while closely monitoring blood pressure and signs and symptoms of CNS and respiratory depression.
Morphine: (Major) Concomitant use of morphine with carisoprodol may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. For extended-release morphine tablets (MS Contin and Morphabond), start with 15 mg every 12 hours. Morphine; naltrexone should be initiated at 1/3 to 1/2 the recommended starting dosage. Educate patients about the risks and symptoms of respiratory depression and sedation. (Major) Concomitant use of morphine with codeine can potentiate the effects of morphine on respiration, blood pressure, and alertness. Profound sedation and coma may also occur. Prior to concurrent use, assess the level of tolerance to CNS depression that has developed and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. A reduced dosage of morphine and/or codeine is recommended; for extended-release morphine products, start with the lowest possible dose of morphine (i.e., 15 mg PO every 12 hours, extended-release tablets; 30 mg or less PO every 24 hours; extended-release capsules). Monitor patients for sedation and respiratory depression.
Morphine; Naltrexone: (Major) Concomitant use of morphine with carisoprodol may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. For extended-release morphine tablets (MS Contin and Morphabond), start with 15 mg every 12 hours. Morphine; naltrexone should be initiated at 1/3 to 1/2 the recommended starting dosage. Educate patients about the risks and symptoms of respiratory depression and sedation. (Major) Concomitant use of morphine with codeine can potentiate the effects of morphine on respiration, blood pressure, and alertness. Profound sedation and coma may also occur. Prior to concurrent use, assess the level of tolerance to CNS depression that has developed and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. A reduced dosage of morphine and/or codeine is recommended; for extended-release morphine products, start with the lowest possible dose of morphine (i.e., 15 mg PO every 12 hours, extended-release tablets; 30 mg or less PO every 24 hours; extended-release capsules). Monitor patients for sedation and respiratory depression.
Mycophenolate: (Moderate) Mycophenolic acid is more than 98% bound to albumin. Concurrent use of mycophenolate with salicylates can decrease the protein binding of mycophenolic acid resulting in an increase in the free fraction of MPA. Patients should be observed for increased clinical effects from mycophenolate as well as additive adverse effects.
Nabilone: (Major) Avoid coadministration of opioid agonists with nabilone due to the risk of additive CNS depression. (Major) Avoid use together if possible. Use of nabilone with skeletal muscle relaxants can potentiate the CNS depressant effects of nabilone on sedation, dizziness and other side effects, which can impair the ability to undertake tasks requiring mental alertness.
Nabumetone: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
Nafcillin: (Moderate) Concomitant use of codeine with nafcillin can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If nafcillin is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Nafcillin is a moderate CYP3A4 inducer. (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Nalbuphine: (Major) Avoid the concomitant use of nalbuphine and opiate agonists, such as codeine. Nalbuphine is a mixed opiate agonist/antagonist that may block the effects of opiate agonists and reduce analgesic effects of acetaminophen; codeine. Nalbuphine may cause withdrawal symptoms in patients receiving chronic opiate agonists. Concurrent use of nalbuphine opiate agonist used; antagonistic effects are more common at low to moderate doses of the opiate agonist. (Major) Concomitant use of nalbuphine with carisoprodol may cause excessive sedation and somnolence. Limit the use of nalbuphine with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations.
Naltrexone: (Major) When naltrexone is used as adjuvant treatment of opiate or alcohol dependence, use is contraindicated in patients currently receiving opiate agonists. Naltrexone will antagonize the therapeutic benefits of opiate agonists and will induce a withdrawal reaction in patients with physical dependence to opioids. An opiate antagonist should only be administered to a patient taking codeine with clinically significant respiratory or cardiovascular depression. Also, patients should be opiate-free for at least 7-10 days prior to initiating naltrexone therapy. If there is any question of opioid use in the past 7-10 days and the patient is not experiencing opioid withdrawal symptoms and/or the urine is negative for opioids, a naloxone challenge test needs to be performed. If a patient receives naltrexone, and an opiate agonist is needed for an emergency situation, large doses of opiate agonists may ultimately overwhelm naltrexone antagonism of opiate receptors. Immediately following administration of exogenous opiate agonists, the opiate plasma concentration may be sufficient to overcome naltrexone competitive blockade, but the patient may experience deeper and more prolonged respiratory depression and thus, may be in danger of respiratory arrest and circulatory collapse. Non-receptor mediated actions like facial swelling, itching, generalized erythema, or bronchoconstriction may occur presumably due to histamine release. A rapidly acting opiate agonist is preferred as the duration of respiratory depression will be shorter. Patients receiving naltrexone may also experience opiate side effects with low doses of opiate agonists. If the opiate agonist is taken in such a way that high concentrations remain in the body beyond the time naltrexone exerts its therapeutic effects, serious side effects may occur.
Naproxen: (Major) Concomitant use of analgesic doses of aspirin and naproxen is generally not recommended due to the increased risk of bleeding and renal impairment. Because there may be an increased risk of cardiovascular events after discontinuation of naproxen due to the interference with the antiplatelet effect of aspirin during the washout period, for patients taking low-dose aspirin for cardioprotection who require intermittent analgesics, consider use of an NSAID that does not interfere with the antiplatelet effect of aspirin, or non-NSAID analgesics as appropriate. A pharmacodynamic study demonstrated that lower dose naproxen (220mg/day or 220mg twice daily) interfered with the antiplatelet effect of low-dose immediate-release aspirin, with the interaction most marked during the washout period of naproxen. There is reason to expect that the interaction would be present with prescription doses of naproxen or with enteric-coated low-dose aspirin; however, the peak interference with aspirin function may be later than observed in the study due to the longer washout period. A decrease in antiplatelet activity was observed at 24 hours after 10 days of naproxen 220 mg/day with low-dose immediate-release aspirin 81 mg/day (93.1%) vs. aspirin alone (98.7%). The interaction was observed even after discontinuation of naproxen on day 11 while aspirin therapy continued but normalized by day 13. The interaction was greater when naproxen was given 30 minutes before aspirin (87.7% vs. 98.7%) and minimal when aspirin was administered 30 minutes before naproxen (95.4% vs. 98.7%). The interaction was minimal at 24 hours after day 10 when naproxen 220 mg twice daily was given 30 minutes before low-dose immediate-release aspirin (95.7% vs. 98.7%); however, the interaction was greater on day 11 after naproxen discontinuation (84.3% vs. 98.7%) and did not normalize by day 13 (90.7% vs. 98.5%). Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone. Naproxen is not a substitute for low dose aspirin for cardiovascular protection.
Naproxen; Esomeprazole: (Major) Concomitant use of analgesic doses of aspirin and naproxen is generally not recommended due to the increased risk of bleeding and renal impairment. Because there may be an increased risk of cardiovascular events after discontinuation of naproxen due to the interference with the antiplatelet effect of aspirin during the washout period, for patients taking low-dose aspirin for cardioprotection who require intermittent analgesics, consider use of an NSAID that does not interfere with the antiplatelet effect of aspirin, or non-NSAID analgesics as appropriate. A pharmacodynamic study demonstrated that lower dose naproxen (220mg/day or 220mg twice daily) interfered with the antiplatelet effect of low-dose immediate-release aspirin, with the interaction most marked during the washout period of naproxen. There is reason to expect that the interaction would be present with prescription doses of naproxen or with enteric-coated low-dose aspirin; however, the peak interference with aspirin function may be later than observed in the study due to the longer washout period. A decrease in antiplatelet activity was observed at 24 hours after 10 days of naproxen 220 mg/day with low-dose immediate-release aspirin 81 mg/day (93.1%) vs. aspirin alone (98.7%). The interaction was observed even after discontinuation of naproxen on day 11 while aspirin therapy continued but normalized by day 13. The interaction was greater when naproxen was given 30 minutes before aspirin (87.7% vs. 98.7%) and minimal when aspirin was administered 30 minutes before naproxen (95.4% vs. 98.7%). The interaction was minimal at 24 hours after day 10 when naproxen 220 mg twice daily was given 30 minutes before low-dose immediate-release aspirin (95.7% vs. 98.7%); however, the interaction was greater on day 11 after naproxen discontinuation (84.3% vs. 98.7%) and did not normalize by day 13 (90.7% vs. 98.5%). Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone. Naproxen is not a substitute for low dose aspirin for cardiovascular protection. (Minor) Esomeprazole may inhibit the CYP2C19 isoenzyme, leading to increased plasma levels of drugs that are substrates for the CYP2C19 isoenzyme, such as carisoprodol. Carisoprdol is metabolized in the liver by CYP2C19 to form meprobamate. Coadministration may result in increased exposure to carisoprdol and decreased exposure of meprobamate.
Naproxen; Pseudoephedrine: (Major) Concomitant use of analgesic doses of aspirin and naproxen is generally not recommended due to the increased risk of bleeding and renal impairment. Because there may be an increased risk of cardiovascular events after discontinuation of naproxen due to the interference with the antiplatelet effect of aspirin during the washout period, for patients taking low-dose aspirin for cardioprotection who require intermittent analgesics, consider use of an NSAID that does not interfere with the antiplatelet effect of aspirin, or non-NSAID analgesics as appropriate. A pharmacodynamic study demonstrated that lower dose naproxen (220mg/day or 220mg twice daily) interfered with the antiplatelet effect of low-dose immediate-release aspirin, with the interaction most marked during the washout period of naproxen. There is reason to expect that the interaction would be present with prescription doses of naproxen or with enteric-coated low-dose aspirin; however, the peak interference with aspirin function may be later than observed in the study due to the longer washout period. A decrease in antiplatelet activity was observed at 24 hours after 10 days of naproxen 220 mg/day with low-dose immediate-release aspirin 81 mg/day (93.1%) vs. aspirin alone (98.7%). The interaction was observed even after discontinuation of naproxen on day 11 while aspirin therapy continued but normalized by day 13. The interaction was greater when naproxen was given 30 minutes before aspirin (87.7% vs. 98.7%) and minimal when aspirin was administered 30 minutes before naproxen (95.4% vs. 98.7%). The interaction was minimal at 24 hours after day 10 when naproxen 220 mg twice daily was given 30 minutes before low-dose immediate-release aspirin (95.7% vs. 98.7%); however, the interaction was greater on day 11 after naproxen discontinuation (84.3% vs. 98.7%) and did not normalize by day 13 (90.7% vs. 98.5%). Controlled clinical studies showed that the concomitant use of NSAIDs and analgesic doses of aspirin does not produce any greater therapeutic effect than the use of NSAIDs alone. In a clinical study, the concomitant use of an NSAID and aspirin was associated with a significantly increased incidence of GI adverse reactions as compared to use of the NSAID alone. Naproxen is not a substitute for low dose aspirin for cardiovascular protection.
Naratriptan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor agonists. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Nateglinide: (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of antidiabetic agents. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose or use of greater than maximum recommended daily dosages, salicylates can cause either hypoglycemia or hyperglycemia. Large doses of aspirin should be used cautiously in patients who receive antidiabetic agents.
Nefazodone: (Moderate) Concomitant use of codeine with nefazodone may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. Additionally, the concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinue codeine if serotonin syndrome occurs. Discontinuation of nefazodone could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If nefazodone is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Nefazodone is a strong inhibitor of CYP3A4.
Nelfinavir: (Moderate) Concomitant use of codeine with nelfinavir may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of nelfinavir could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If nelfinavir is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Nelfinavir is a strong inhibitor of CYP3A4.
Neostigmine; Glycopyrrolate: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and glycopyrrolate use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Nesiritide, BNP: (Major) The potential for hypotension may be increased when coadministering nesiritide with opiate agonists.
Netupitant, Fosnetupitant; Palonosetron: (Moderate) Concomitant use of codeine with netupitant may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of netupitant could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If netupitant is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Netupitant is a moderate inhibitor of CYP3A4.
Nevirapine: (Moderate) Monitor for reduced efficacy of codeine and signs of opioid withdrawal in patients who have developed physical dependence if coadministration with nevirapine is necessary; consider increasing the dose of codeine as needed. It is recommended to avoid this combination when codeine is being used for cough. If nevirapine is discontinued, consider a dose reduction of codeine and frequently monitor for signs of respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Nevirapine is a weak CYP3A inducer. Concomitant use with nevirapine can increase norcodeine levels via increased CYP3A metabolism, resulting in decreased metabolism via CYP2D6 resulting in lower morphine levels; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence.
Nilotinib: (Moderate) Concomitant use of codeine with nilotinib may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of nilotinib could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If nilotinib is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Nilotinib is a moderate inhibitor of CYP3A4.
Niraparib; Abiraterone: (Moderate) Concomitant use of codeine with abiraterone may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of abiraterone could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If abiraterone is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Abiraterone is a moderate inhibitor of CYP2D6.
Nirmatrelvir; Ritonavir: (Major) Consider withholding codeine if clinically appropriate during receipt of ritonavir-boosted nirmatrelvir. If this is not feasible, consider an alternative COVID-19 therapy. Coadministration may increase codeine exposure, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Nirmatrelvir is a CYP3A inhibitor. (Moderate) Concomitant use of codeine with ritonavir may alter codeine plasma concentrations, resulting in an unpredictable effect such as reduced efficacy or symptoms of opioid withdrawal or prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage adjustment of codeine until stable drug effects are achieved. Discontinuation of ritonavir could alter codeine plasma concentrations, resulting in an unpredictable effect such as prolonged opioid adverse reactions or decreased opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If ritonavir is discontinued, monitor the patient carefully and consider adjusting the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Ritonavir is a strong inhibitor of CYP3A4 and a weak inhibitor of CYP2D6. CYP3A4 inhibitors may increase codeine-related adverse effects while CYP2D6 inhibitors may reduce efficacy.
Nitazoxanide: (Moderate) The active metabolite of nitazoxanide, tizoxanide, is highly bound to plasma proteins. Caution should be exercised when administering nitazoxanide concurrently with other highly plasma protein-bound drugs with narrow therapeutic indices because competition for binding sites may occur.
Nitroglycerin: (Moderate) When coadministered with aspirin, ASA (doses between 500 mg and 1000 mg), the maximum plasma concentration (Cmax) and exposure (AUC) of a single nitroglycerin dose is increased by 67% and 73%, respectively. Additionally, limited data suggest that patients receiving aspirin, ASA in high doses can exhibit an exaggerated response to sublingual nitroglycerin. Although hypotension and tachycardia were more significant during concomitant therapy, no special precautions appear necessary. The pharmacologic effects of 0.4% nitroglycerin rectal ointment may also be enhanced when administered concomitantly with aspirin, ASA; therefore, close clinical monitoring is advised. (Minor) Nitroglycerin can cause hypotension. This action may be additive with other agents that can cause hypotension such as opiate agonists. Patients should be monitored more closely for hypotension if nitroglycerin is used concurrently with opiate agonists.
Nortriptyline: (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Moderate) Concomitant use of carisoprodol with tricyclic antidepressants can result in additive CNS depression (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Odevixibat: (Moderate) Monitor for reduced efficacy of codeine and signs of opioid withdrawal in patients who have developed physical dependence if coadministration with odevixibat is necessary; consider increasing the dose of codeine as needed. It is recommended to avoid this combination when codeine is being used for cough. If odevixibat is discontinued, consider a dose reduction of codeine and frequently monitor for signs of respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Odevixibat is a weak CYP3A inducer. Concomitant use with odevixibat can increase norcodeine levels via increased CYP3A metabolism, resulting in decreased metabolism via CYP2D6 resulting in lower morphine levels; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence.
Olanzapine: (Major) Concomitant use of opioid agonists with olanzapine may cause excessive sedation and somnolence. Limit the use of opioid pain medications with olanzapine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking olanzapine.
Olanzapine; Fluoxetine: (Major) Concomitant use of opioid agonists with olanzapine may cause excessive sedation and somnolence. Limit the use of opioid pain medications with olanzapine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking olanzapine. (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and fluoxetine because of the potential risk of serotonin syndrome, reduced codeine efficacy, and potential for opioid withdrawal symptoms. Discontinue codeine if serotonin syndrome is suspected. It is recommended to avoid this combination when codeine is being used for cough. Concomitant use may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of fluoxetine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If fluoxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Fluoxetine is a strong inhibitor of CYP2D6. (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation. (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as fluoxetine, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
Olanzapine; Samidorphan: (Contraindicated) Salmidorphan is contraindicated in patients who are using opiate agonists or undergoing acute opioid withdrawal. Salmidorphan increases the risk of precipitating acute opioid withdrawal in patients dependent on opioids. Before initiating salmidorphan, there should be at least a 7-day opioid-free interval from the last use of short-acting opioids, and at least a 14-day opioid-free interval from the last use of long-acting opioids. In emergency situations, if a salmidorphan-treated patient requires opiates for anesthesia or analgesia, discontinue salmidorphan. The opiate agonist should be administered by properly trained individual(s), and the patient properly monitored in a setting equipped and staffed for cardiopulmonary resuscitation. In non-emergency situations, if a salmidorphan-treated patient requires opiate agonist treatment (e.g., for analgesia) discontinue salmidorphan at least 5 days before opioid treatment. Salmidorphan, as an opioid antagonist, may cause opioid treatment to be less effective or ineffective shortly after salmidorphan discontinuation. (Major) Concomitant use of opioid agonists with olanzapine may cause excessive sedation and somnolence. Limit the use of opioid pain medications with olanzapine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking olanzapine.
Oliceridine: (Major) Concomitant use of oliceridine with carisoprodol may cause excessive sedation and somnolence. Limit the use of oliceridine with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. (Major) Concomitant use of oliceridine with codeine may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of oliceridine with codeine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medications in patients taking other opioid agonists. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Olmesartan; Amlodipine; Hydrochlorothiazide, HCTZ: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for an increase in codeine-related adverse reactions including sedation and respiratory depression if coadministration with amlodipine is necessary; adjust the dose of codeine if necessary. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Amlodipine is a weak CYP3A4 inhibitor. Concomitant use may result in an increase in codeine plasma concentrations, resulting in greater metabolism by CYP2D6 and increased morphine concentrations. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Olmesartan; Hydrochlorothiazide, HCTZ: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Olutasidenib: (Moderate) Monitor for reduced efficacy of codeine and signs of opioid withdrawal in patients who have developed physical dependence if coadministration with olutasidenib is necessary; consider increasing the dose of codeine as needed. It is recommended to avoid this combination when codeine is being used for cough. If olutasidenib is discontinued, consider a dose reduction of codeine and frequently monitor for signs of respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Olutasidenib is a weak CYP3A inducer. Concomitant use with olutasidenib can increase norcodeine levels via increased CYP3A metabolism, resulting in decreased metabolism via CYP2D6 resulting in lower morphine levels; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence.
Omacetaxine: (Major) Avoid the concomitant use of omacetaxine and aspirin, ASA when the platelet count is less than 50,000 cells/microliter due to an increased risk of bleeding. Also, aspirin may mask signs of infection such as fever and pain in patients following treatment with antineoplastic agents or immunosuppressives. Aspirin, ASA should be used with caution in patients receiving immunosuppressive therapy. Special consideration should be given to myelosuppressed patients prior to receiving aspirin.
Omaveloxolone: (Moderate) Monitor for reduced efficacy of codeine and signs of opioid withdrawal in patients who have developed physical dependence if coadministration with omaveloxolone is necessary; consider increasing the dose of codeine as needed. It is recommended to avoid this combination when codeine is being used for cough. If omaveloxolone is discontinued, consider a dose reduction of codeine and frequently monitor for signs of respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Omaveloxolone is a weak CYP3A inducer. Concomitant use with omaveloxolone can increase norcodeine levels via increased CYP3A metabolism, resulting in decreased metabolism via CYP2D6 resulting in lower morphine levels; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence.
Omeprazole: (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as omeprazole, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
Omeprazole; Amoxicillin; Rifabutin: (Moderate) Concomitant use of codeine with rifabutin can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If rifabutin is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Rifabutin is a moderate CYP3A4 inducer. (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as omeprazole, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects. (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Omeprazole; Sodium Bicarbonate: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid. (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as omeprazole, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
Ondansetron: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Opicapone: (Moderate) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including skeletal muscle relaxants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Oritavancin: (Moderate) Carisoprodol is metabolized by CYP2C19; oritavancin is a weak CYP2C19 inhibitor. Coadministration may result in elevated carisoprodol plasma concentrations. If these drugs are administered concurrently, monitor patients for signs of carisoprodol toxicity, such as extreme drowsiness, confusion, or a slowed rate of breathing. (Moderate) Codeine is metabolized by CYP2D6; oritavancin is a weak CYP2D6 inducer. Plasma concentrations and efficacy of codeine may be reduced if these drugs are administered concurrently.
Orphenadrine: (Major) Concomitant use of opioid agonists with orphenadrine may cause excessive sedation and somnolence. Limit the use of opioid pain medications with orphenadrine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Avoid prescribing opioid cough medication in patients taking orphenadrine.
Osilodrostat: (Moderate) Concomitant use of codeine with osilodrostat may alter codeine plasma concentrations, resulting in an unpredictable effect such as reduced efficacy or symptoms of opioid withdrawal or prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage adjustment of codeine until stable drug effects are achieved. Discontinuation of osilodrostat could alter codeine plasma concentrations, resulting in an unpredictable effect such as prolonged opioid adverse reactions or decreased opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If osilodrostat is discontinued, monitor the patient carefully and consider adjusting the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Osilodrostat is a weak inhibitor of CYP3A4 and CYP2D6. CYP3A4 inhibitors may increase codeine-related adverse effects while CYP2D6 inhibitors may reduce efficacy.
Oxacillin: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Oxaprozin: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
Oxazepam: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Moderate) Concomitant use of skeletal muscle relaxants with benzodiazepines can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take benzodiazepines with another CNS depressant for symptoms of excess sedation.
Oxcarbazepine: (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. Theoretically, CY2C19 inhibitors, such as oxcarbazepine, could increase carisoprodol plasma levels, with potential for enhanced CNS depressant effects.
Oxybutynin: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and oxybutynin use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Oxycodone: (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Reduce the initial oxycodone dosage by one-third to one-half when using the extended-release tablets. (Major) Concomitant use of oxycodone with other opiate agonists may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Prior to concurrent use of oxycodone in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. If a CNS depressant is used concurrently with oxycodone, a reduced dosage of oxycodone and/or the CNS depressant is recommended; use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor for sedation and respiratory depression.
Oxymorphone: (Major) Concomitant use of opioid agonists with carisoprodol may cause excessive sedation and somnolence. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Reduce the initial oxymorphone dosage by one-third to one-half. (Major) Concomitant use of oxymorphone with other CNS depressants may produce additive CNS depressant effects. Respiratory depression, hypotension, profound sedation, or coma may result from combination therapy. Prior to concurrent use of oxymorphone in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. Oxymorphone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxymorphone at one-third to one-half the usual dosage in patients that are concurrently receiving another CNS depressant. Also consider a using a lower dose of the CNS depressant. Slowly titrate the dose as necessary for adequate pain relief and monitor for sedation or respiratory depression.
Ozanimod: (Contraindicated) Do not use codeine in patients taking MAOIs or within 14 days of stopping them. An active metabolite of ozanimod inhibits MAO-B. MAO inhibitor interactions with codeine may manifest as serotonin syndrome, hypertensive crisis, or opioid toxicity (e.g., respiratory depression, coma). Although a small number of patients treated with ozanimod were concomitantly exposed to opioids, this exposure was not adequate to rule out the possibility of an adverse reaction from coadministration.
Pacritinib: (Moderate) Concomitant use of codeine with pacritinib may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of pacritinib could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If pacritinib is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Pacritinib is a weak inhibitor of CYP3A.
Palbociclib: (Moderate) Monitor for an increase in codeine-related adverse reactions, including sedation and respiratory depression, if coadministration with palbociclib is necessary; consider reducing the dose of codeine if clinically appropriate. If palbociclib is discontinued, monitor for evidence of opioid withdrawal until stable drug effects are achieved and consider increasing the codeine dose if necessary. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Palbociclib is a CYP3A4 inhibitor. Concomitant use may result in an increase in codeine plasma concentrations, resulting in greater metabolism by CYP2D6 and increased morphine concentrations.
Paliperidone: (Moderate) Drugs that can cause CNS depression such as opiate agonists, if used concomitantly with paliperidone, can increase both the frequency and the intensity of adverse effects such as drowsiness, sedation, and dizziness. Monitor for signs and symptoms of CNS depression and advise patients to avoid driving or engaging in other activities requiring mental alertness until they know how this combination affects them.
Palonosetron: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with serotonin-receptor antagonists. The development of serotonin syndrome has been reported with 5-HT3 receptor antagonists, mostly when used in combination with other serotonergic medications. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Pamidronate: (Moderate) Monitor renal function during concomitant pamidronate and aspirin use due to risk for additive nephrotoxicity.
Panobinostat: (Moderate) Concomitant use of codeine with panobinostat may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of panobinostat could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If panobinostat is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Panobinostat is a moderate inhibitor of CYP2D6.
Paroxetine: (Moderate) Careful monitoring, particularly during treatment initiation and dose adjustment, is recommended during coadministration of codeine and paroxetine because of the potential risk of serotonin syndrome, reduced codeine efficacy, and potential for opioid withdrawal symptoms. Discontinue codeine if serotonin syndrome is suspected. It is recommended to avoid this combination when codeine is being used for cough. Concomitant use may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. Monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of paroxetine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If paroxetine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Paroxetine is a strong inhibitor of CYP2D6. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. (Moderate) The combined use of selective serotonin reuptake inhibitors and aspirin, ASA may elevate the risk for an upper GI bleed. SSRIs may inhibit serotonin uptake by platelets, augmenting the antiplatelet effects of aspirin. Additionally, aspirin impairs the gastric mucosa defenses by inhibiting prostaglandin formation.
Peginterferon Alfa-2b: (Moderate) Peginterferon alfa-2b inhibits CYP2D6. Exposure of drugs metabolized by CYP2D6 such as codeine may be increased when co-administered with peginterferon alfa-2b. The pharmacological activity of codeine is due to its conversion to morphine via the cytochrome CYP2D6 hepatic isoenzyme. Codeine has a low affinity for CYP2D6; therefore, its analgesic activity may vary greatly when it is combined with drugs that inhibit CYP2D6. Therefore, appropriate monitoring and dose adjustment may be necessary.
Pegvisomant: (Moderate) In clinical trials, patients taking opiate agonists often required higher serum pegvisomant concentrations to achieve appropriate IGF-I suppression compared with patients not receiving opiate agonists. The mechanism of this interaction is unknown.
Penicillin G Benzathine: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Penicillin G Benzathine; Penicillin G Procaine: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Penicillin G Procaine: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Penicillin G: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Penicillin V: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Penicillins: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Pentazocine: (Major) Avoid the concomitant use of pentazocine and opiate agonists, such as codeine. Pentazocine is a mixed opiate agonist/antagonist that may block the effects of mu-receptor opiate agonists and reduce analgesic effects of codeine. Pentazocine may cause withdrawal symptoms in patients receiving chronic opiate agonists. Concurrent use of pentazocine with other opiate agonists can cause addit ive CNS, respiratory, and hypotensive effects. The additive or antagonistic effects are dependent upon the dose of the opiate agonist used; antagonistic effects are more common at low to moderate doses of the opiate agonist. (Major) Concomitant use of pentazocine with carisoprodol may cause respiratory depression, profound sedation, and death. Limit the use of pentazocine with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Consider prescribing naloxone for the emergency treatment of opioid overdose.
Pentazocine; Naloxone: (Major) Avoid the concomitant use of pentazocine and opiate agonists, such as codeine. Pentazocine is a mixed opiate agonist/antagonist that may block the effects of mu-receptor opiate agonists and reduce analgesic effects of codeine. Pentazocine may cause withdrawal symptoms in patients receiving chronic opiate agonists. Concurrent use of pentazocine with other opiate agonists can cause additive CNS, respiratory, and hypotensive effects. The additive or antagonistic effects are dependent upon the dose of the opiate agonist used; antagonistic effects are more common at low to moderate doses of the opiate agonist. (Major) Concomitant use of pentazocine with carisoprodol may cause respiratory depression, profound sedation, and death. Limit the use of pentazocine with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Consider prescribing naloxone for the emergency treatment of opioid overdose.
Pentobarbital: (Major) Concomitant use of codeine with barbiturates may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with barbiturates to only patients for whom alternative treatment options are inadequate. It is recommended to avoid this combination when codeine is being used for cough. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Additionally, concomitant use of codeine with a barbiturate can decrease codeine concentrations, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. Monitor for reduced efficacy of codeine and signs of opioid withdrawal. Discontinuation of a barbiturate may increase the risk of opioid-related adverse reactions, such as fatal respiratory depression. Barbiturates induce CYP3A4. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. (Moderate) Concomitant use of skeletal muscle relaxants with barbiturates can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take barbiturates with another CNS depressant for symptoms of excess sedation.
Pentosan: (Moderate) Pentosan is a weak anticoagulant. Pentosan has 1/15 the anticoagulant activity of heparin. An additive risk of bleeding may be seen in patients receiving other platelet inhibitors (e.g., aspirin, ASA) in combination with pentosan. Also, large doses of salicylates (>= 3-4 g/day) can cause hypoprothrombinemia, an additional risk factor for bleeding.
Pentoxifylline: (Moderate) The concomitant administration of platelet inhibitor with pentoxifylline in the treatment of intermittent claudication has not been evaluated and should be approached with caution, due to the potential for synergistic effects.
Perampanel: (Moderate) Co-administration of perampanel with CNS depressants, including ethanol, may increase CNS depression. The combination of perampanel (particularly at high doses) with ethanol has led to decreased mental alertness and ability to perform complex tasks (such as driving), as well as increased levels of anger, confusion, and depression; similar reactions should be expected with concomitant use of other CNS depressants, such as carisoprodol. (Moderate) Concomitant use of opioid agonists with perampanel may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking perampanel. Limit the use of opioid pain medications with perampanel to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression.
Perindopril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
Perindopril; Amlodipine: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Moderate) Monitor for an increase in codeine-related adverse reactions including sedation and respiratory depression if coadministration with amlodipine is necessary; adjust the dose of codeine if necessary. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Amlodipine is a weak CYP3A4 inhibitor. Concomitant use may result in an increase in codeine plasma concentrations, resulting in greater metabolism by CYP2D6 and increased morphine concentrations.
Perphenazine: (Moderate) Concomitant use of opioid agonists with perphenazine may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking perphenazine. Limit the use of opioid pain medications with perphenazine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. (Moderate) Phenothiazines can potentiate the CNS-depressant action of other drugs such as skeletal muscle relaxants. Caution should be exercised during simultaneous use of these agents due to potential for additive hypotension and excessive CNS effects (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Perphenazine; Amitriptyline: (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Moderate) Concomitant use of carisoprodol with tricyclic antidepressants can result in additive CNS depression (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness. (Moderate) Concomitant use of opioid agonists with perphenazine may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking perphenazine. Limit the use of opioid pain medications with perphenazine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. (Moderate) Phenothiazines can potentiate the CNS-depressant action of other drugs such as skeletal muscle relaxants. Caution should be exercised during simultaneous use of these agents due to potential for additive hypotension and excessive CNS effects (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Pertuzumab; Trastuzumab; Hyaluronidase: (Minor) Salicylates, when given in large systemic doses, may render tissues partially resistant to the action of hyaluronidase. Patients receiving these medications may require larger amounts of hyaluronidase for equivalent dispersing effect.
Pexidartinib: (Moderate) Monitor for reduced efficacy of codeine and signs of opioid withdrawal in patients who have developed physical dependence if coadministration with pexidartinib is necessary; consider increasing the dose of codeine as needed. It is recommended to avoid this combination when codeine is being used for cough. If pexidartinib is discontinued, consider a dose reduction of codeine, and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Pexidartinib is a moderate CYP3A4 inducer. Concomitant use with pexidartinib can increase norcodeine levels via increased CYP3A4 metabolism, resulting in decreased metabolism via CYP2D6 resulting in lower morphine levels; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence.
Phenelzine: (Contraindicated) Codeine use is contraindicated in patients who are receiving or who have received monoamine oxidase inhibitors (MAOIs) within the previous 14 days due to a risk for serotonin syndrome or opioid toxicity, including respiratory depression. Concomitant use of codeine with other serotonergic drugs such as MAOIs may result in serious adverse effects including serotonin syndrome. MAOIs may cause additive CNS depression, respiratory depression, drowsiness, dizziness, or hypotension when used with opiate agonists such as codeine. If urgent use of an opioid is necessary, use test doses and frequent titration of small doses of alternate opioids to treat pain while closely monitoring blood pressure and signs and symptoms of CNS and respiratory depression.
Phenobarbital: (Major) Concomitant use of codeine with barbiturates may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with barbiturates to only patients for whom alternative treatment options are inadequate. It is recommended to avoid this combination when codeine is being used for cough. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Additionally, concomitant use of codeine with a barbiturate can decrease codeine concentrations, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. Monitor for reduced efficacy of codeine and signs of opioid withdrawal. Discontinuation of a barbiturate may increase the risk of opioid-related adverse reactions, such as fatal respiratory depression. Barbiturates induce CYP3A4. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. (Moderate) Concomitant use of skeletal muscle relaxants with barbiturates can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take barbiturates with another CNS depressant for symptoms of excess sedation.
Phenobarbital; Hyoscyamine; Atropine; Scopolamine: (Major) Concomitant use of codeine with barbiturates may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with barbiturates to only patients for whom alternative treatment options are inadequate. It is recommended to avoid this combination when codeine is being used for cough. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Additionally, concomitant use of codeine with a barbiturate can decrease codeine concentrations, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. Monitor for reduced efficacy of codeine and signs of opioid withdrawal. Discontinuation of a barbiturate may increase the risk of opioid-related adverse reactions, such as fatal respiratory depression. Barbiturates induce CYP3A4. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. (Major) Reserve concomitant use of codeine and atropine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Major) Reserve concomitant use of codeine and scopolamine for patients in whom alternate treatment options are inadequate. Limit dosages and durations to the minimum required and monitor patients closely for respiratory depression and sedation. If concomitant use is necessary, consider prescribing naloxone for the emergency treatment of opioid overdose and monitor for signs of urinary retention or reduced gastric motility. Concomitant use can increase the risk of hypotension, respiratory depression, profound sedation, coma, and death as well as urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Concomitant use of skeletal muscle relaxants with barbiturates can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take barbiturates with another CNS depressant for symptoms of excess sedation. (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and hyoscyamine use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Phenothiazines: (Moderate) Phenothiazines can potentiate the CNS-depressant action of other drugs such as skeletal muscle relaxants. Caution should be exercised during simultaneous use of these agents due to potential for additive hypotension and excessive CNS effects (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Phenytoin: (Moderate) Concomitant use of codeine with phenytoin can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If phenytoin is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Phenytoin is a strong CYP3A4 inducer. (Minor) Carisoprodol is extensively metabolized and is a significant substrate of CYP2C19 isoenzymes. If carisoprodol is combined with an inducer of hepatic enzymes, such as phenytoin, the potential exists for increased metabolism of carisoprodol and meprobamate, the active metabolite, plasma concentrations could be increased. (Minor) Large doses of salicylates can displace phenytoin from plasma protein-binding sites. Although increased serum concentrations of unbound phenytoin may lead to phenytoin toxicity, the liver may also more rapidly clear unbound drug. Displacement of phenytoin from binding sites can lead to a decrease in the total phenytoin serum concentration. Close monitoring for excessive phenytoin toxicity or decreased phenytoin efficacy is recommended.
Phosphorated Carbohydrate Solution: (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
Phosphorus: (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
Photosensitizing agents (topical): (Minor) Preclinical data suggest that agents that affect platelet function and inhibit prostaglandin synthesis could decrease the efficacy of photosensitizing agents used during photodynamic therapy.
Pimozide: (Moderate) Concomitant use of codeine with other central nervous system (CNS) depressants, such as pimozide, can potentiate the effects of codeine and may lead to additive CNS or respiratory depression, profound sedation, or coma. Prior to concurrent use of codeine in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. If these agents are used together, a reduced dosage of codeine may be required. Carefully monitor the patient for hypotension, CNS depression, and respiratory depression. Carbon dioxide retention from opioid-induced respiratory depression can exacerbate the sedating effects of opioids.
Pioglitazone: (Moderate) Monitor blood glucose during concomitant thiazolidinedione and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Pioglitazone; Glimepiride: (Moderate) Monitor blood glucose during concomitant sulfonylurea and aspirin use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Pioglitazone; Metformin: (Moderate) Monitor blood glucose during concomitant metformin and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia. (Moderate) Monitor blood glucose during concomitant thiazolidinedione and salicylate use. Concomitant use may cause an increased blood glucose-lowering effect with risk of hypoglycemia.
Piperacillin; Tazobactam: (Minor) Due to the high protein binding of aspirin, it could displace or be displaced from binding sites by other highly protein-bound drugs, such as penicillins. Also, aspirin may compete with penicillin for renal tubular secretion, increasing penicillin serum concentrations. Overall, this combination should be used with caution and patients monitored for increased side effects.
Piroxicam: (Major) The concurrent use of aspirin with other NSAIDs should be avoided because this may increase bleeding or lead to decreased renal function. The use of salicylates together with NSAIDs can also lead to additive GI toxicity.
Pirtobrutinib: (Moderate) Concomitant use of codeine with pirtobrutinib may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of pirtobrutinib could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If pirtobrutinib is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Pirtobrutinib is a weak inhibitor of CYP3A.
Pneumococcal Vaccine, Polyvalent: (Moderate) Concomitant administration of antipyretics, such as aspirin, ASA, may decrease an individual's immunological response to the pneumococcal vaccine. A post-marketing study conducted in Poland using a non-US vaccination schedule (2, 3, 4, and 12 months of age) evaluated the impact of prophylactic oral acetaminophen on antibody responses to Prevnar 13. Data show that acetaminophen, given at the time of vaccination and then dosed at 6 to 8 hour intervals for 3 doses on a scheduled basis, reduced the antibody response to some serotypes after the third dose of Prevnar 13 when compared to the antibody responses of infants who only received antipyretics 'as needed' for treatment. However, reduced antibody responses were not observed after the fourth dose of Prevnar 13 with prophylactic acetaminophen.
Posaconazole: (Moderate) Concomitant use of codeine with posaconazole may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of posaconazole could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If posaconazole is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Posaconazole is a strong inhibitor of CYP3A4.
Potassium Bicarbonate: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid. (Moderate) Urinary alkalinizing agents, like potassium citrate, increase the excretion of salicylates by increasing renal clearance.
Potassium Chloride: (Moderate) Urinary alkalinizing agents, like potassium citrate, increase the excretion of salicylates by increasing renal clearance.
Potassium Citrate: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid. (Moderate) Urinary alkalinizing agents, like potassium citrate, increase the excretion of salicylates by increasing renal clearance.
Potassium Citrate; Citric Acid: (Moderate) Concurrent administration of high doses of alkalinizing agents may increase urine pH and decrease serum salicylate levels by decreasing renal tubular reabsorption of salicylic acid. (Moderate) Urinary alkalinizing agents, like potassium citrate, increase the excretion of salicylates by increasing renal clearance.
Potassium Phosphate: (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
Potassium Phosphate; Sodium Phosphate: (Moderate) Agents that acidify the urine, like phosphate salts, should be avoided in patients receiving high-dose salicylates. Urine acidifying agents may increase renal tubular reabsorption of salicylic acid and possibly increase salicylic acid levels.
Pramipexole: (Major) Concomitant use of opioid agonists with pramipexole may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking pramipexole. Limit the use of opioid pain medications with pramipexole to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. Dopaminergic agents like pramipexole have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment.
Pramlintide: (Major) Pramlintide slows gastric emptying and the rate of nutrient delivery to the small intestine. Medications with the potential to slow GI motility, such as opiate agonists, should be used with caution, if at all, with pramlintide until more data are available from the manufacturer. Monitor blood glucose. (Moderate) Salicylates can indirectly increase insulin secretion, and thus decrease blood glucose concentrations. In large doses, salicylates may cause hyperglycemia and glycosuria. After acute overdose, aspirin can cause either hypo- or hyperglycemia. Large doses of aspirin should be used cautiously in patients receiving antidiabetic agents.
Prasterone, Dehydroepiandrosterone, DHEA (Dietary Supplements): (Moderate) Prasterone, dehydroepiandrosterone, DHEA appears to have antiplatelet effects, which may prolong bleeding times. Because of these potential, varied effects on coagulation, patients receiving DHEA concurrently with aspirin, should be monitored for side effects or the need for dosage adjustments.
Prasterone, Dehydroepiandrosterone, DHEA (FDA-approved): (Moderate) Prasterone, dehydroepiandrosterone, DHEA appears to have antiplatelet effects, which may prolong bleeding times. Because of these potential, varied effects on coagulation, patients receiving DHEA concurrently with aspirin, should be monitored for side effects or the need for dosage adjustments.
Prasugrel: (Moderate) Although indicated for concomitant use, both prasugrel and aspirin are associated with bleeding. Aspirin 150 mg did not alter prasugrel-mediated inhibition of platelet aggregation; however, bleeding time was increased compared to either drug alone. Monitor for bleeding during concomitant therapy. (Moderate) Consider the use of a parenteral anti-platelet agent for patients with acute coronary syndrome who require concomitant opioid agonists. Coadministration of opioid agonists with prasugrel delays and reduces the absorption of prasugrel's active metabolite due to slowed gastric emptying.
Pregabalin: (Major) Concomitant use of opioid agonists with pregabalin may cause excessive sedation, somnolence, and respiratory depression. Avoid prescribing opioid cough medications in patients taking pregabalin. Limit the use of opioid pain medications with pregabalin to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, initiate pregabalin at the lowest recommended dose and monitor patients for symptoms of respiratory depression and sedation. Use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression and respiratory depression. (Major) Initiate pregabalin at the lowest recommended dose and monitor patients for symptoms of sedation and somnolence during coadministration of pregabalin and carisoprodol. Concomitant use of pregabalin with carisoprodol may cause additive CNS depression. Educate patients about the risks and symptoms of excessive CNS depression.
Prilocaine: (Moderate) The use of these drugs together must be approached with caution. Although commonly used together for additive analgesic effects, the patient must be monitored for respiratory depression, hypotension, and excessive sedation due to additive effects on the CNS and blood pressure. In rare instances, serious morbidity and mortality has occurred. Limit the use of opiate pain medications with local anesthetics to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. The use of the local anesthetic may allow for the use a lower initial dose of the opiate and then the doses can be titrated to proper clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
Prilocaine; Epinephrine: (Moderate) The use of these drugs together must be approached with caution. Although commonly used together for additive analgesic effects, the patient must be monitored for respiratory depression, hypotension, and excessive sedation due to additive effects on the CNS and blood pressure. In rare instances, serious morbidity and mortality has occurred. Limit the use of opiate pain medications with local anesthetics to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. The use of the local anesthetic may allow for the use a lower initial dose of the opiate and then the doses can be titrated to proper clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
Primidone: (Major) Concomitant use of codeine with barbiturates may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with barbiturates to only patients for whom alternative treatment options are inadequate. It is recommended to avoid this combination when codeine is being used for cough. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation. Additionally, concomitant use of codeine with a barbiturate can decrease codeine concentrations, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. Monitor for reduced efficacy of codeine and signs of opioid withdrawal. Discontinuation of a barbiturate may increase the risk of opioid-related adverse reactions, such as fatal respiratory depression. Barbiturates induce CYP3A4. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. (Moderate) Concomitant use of skeletal muscle relaxants with barbiturates can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take barbiturates with another CNS depressant for symptoms of excess sedation.
Probenecid: (Contraindicated) Concurrent use of probenecid and salicylates is contraindicated. The uricosuric actions of probenecid are inhibited by salicylates. When probenecid is used to treat hyperuricemia or gout, do not administer with salicylates.
Probenecid; Colchicine: (Contraindicated) Concurrent use of probenecid and salicylates is contraindicated. The uricosuric actions of probenecid are inhibited by salicylates. When probenecid is used to treat hyperuricemia or gout, do not administer with salicylates.
Procarbazine: (Moderate) Opiate agonists may cause additive sedation or other CNS effects when given in combination with procarbazine.
Prochlorperazine: (Major) Concomitant use of opioid agonists with prochlorperazine may cause excessive sedation and somnolence. Concurrent administration of prochlorperazine is contraindicated in patients receiving large doses of opiate agonists. Avoid prescribing opioid cough medications in patients taking prochlorperazine. Limit the use of opioid pain medications with prochlorperazine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. (Moderate) Phenothiazines can potentiate the CNS-depressant action of other drugs such as skeletal muscle relaxants. Caution should be exercised during simultaneous use of these agents due to potential for additive hypotension and excessive CNS effects (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Promethazine: (Major) Concomitant use of opioid agonists with promethazine may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking promethazine. Limit the use of opioid pain medications with promethazine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce the opioid dose by one-quarter to one-half; use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. (Moderate) Phenothiazines can potentiate the CNS-depressant action of other drugs such as skeletal muscle relaxants. Caution should be exercised during simultaneous use of these agents due to potential for additive hypotension and excessive CNS effects (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Promethazine; Dextromethorphan: (Major) Concomitant use of opioid agonists with promethazine may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking promethazine. Limit the use of opioid pain medications with promethazine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce the opioid dose by one-quarter to one-half; use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering codeine with dextromethorphan. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustment. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Phenothiazines can potentiate the CNS-depressant action of other drugs such as skeletal muscle relaxants. Caution should be exercised during simultaneous use of these agents due to potential for additive hypotension and excessive CNS effects (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Promethazine; Phenylephrine: (Major) Concomitant use of opioid agonists with promethazine may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking promethazine. Limit the use of opioid pain medications with promethazine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce the opioid dose by one-quarter to one-half; use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression. (Moderate) Phenothiazines can potentiate the CNS-depressant action of other drugs such as skeletal muscle relaxants. Caution should be exercised during simultaneous use of these agents due to potential for additive hypotension and excessive CNS effects (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Propafenone: (Moderate) Concomitant use of codeine with propafenone may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of propafenone could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If propafenone is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Propafenone is a moderate inhibitor of CYP2D6.
Propantheline: (Moderate) Monitor for signs of urinary retention or reduced gastric motility during concomitant codeine and propantheline use. Concomitant use may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Propofol: (Major) Concomitant use of codeine with a general anesthetic may cause respiratory depression, hypotension, profound sedation, and death. Avoid prescribing opioid cough medications in patients receiving a general anesthetic. Limit the use of opioid pain medications with a general anesthetic to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation.
Propranolol; Hydrochlorothiazide, HCTZ: (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Protriptyline: (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Moderate) Concomitant use of carisoprodol with tricyclic antidepressants can result in additive CNS depression (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Pseudoephedrine; Triprolidine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with triprolidine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with triprolidine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Psyllium: (Moderate) Psyllium can interfere with the absorption of certain oral drugs if administered concomitantly. For example, psyllium fiber can adsorb salicylates. Per the psyllium manufacturers, administration of other prescribed oral drugs should be separated from the administration of psyllium by at least 2 hours.
Pyrilamine: (Moderate) Carisoprodol is metabolized to meprobamate, a significant CNS depressant. Carisoprodol can cause additive CNS depression if used concomitantly with other CNS depressants. Additive effects of sedation and dizziness, which can impair the ability to undertake tasks requiring mental alertness, may occur if carisoprodol is taken with sedating H1-blockers. Utilize appropriate caution if carisoprodol is coadministered with another CNS depressant. (Moderate) Concomitant use of opioid agonists with pyrilamine may cause excessive sedation and somnolence. Limit the use of opioid pain medication with pyrilamine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect.
Quazepam: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Moderate) Concomitant use of skeletal muscle relaxants with benzodiazepines can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take benzodiazepines with another CNS depressant for symptoms of excess sedation.
Quetiapine: (Major) Concomitant use of opioid agonists with quetiapine may cause excessive sedation and somnolence. Limit the use of opioid pain medications with quetiapine to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking quetiapine.
Quinapril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
Quinapril; Hydrochlorothiazide, HCTZ: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation. (Moderate) Monitor blood pressure as well as for signs of worsening renal function and loss of diuretic efficacy, including antihypertensive effects, during concomitant thiazide diuretic and salicylate use. Salicylate use decreases glomerular filtration rate and renal blood flow, and concomitant diuretic use may increase the risk of this reaction. Salicylates may diminish the effectiveness of diuretics due to inhibition of renal prostaglandins, leading to decreased renal blood flow and salt and fluid retention. (Moderate) Monitor for signs of diminished diuresis and/or effects on blood pressure during coadministration of a thiazide diuretic and codeine; increase the dosage of the thiazide diuretic as needed. Opioids can reduce the efficacy of diuretics by inducing the release of antidiuretic hormone. Opioids may also potentiate orthostatic hypotension when given concomitantly with a thiazide diuretic.
Quinidine: (Moderate) Concomitant use of codeine with quinidine may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of quinidine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If quinidine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Quinidine is a strong inhibitor of CYP2D6.
Quinine: (Moderate) Concomitant use of codeine with quinine may alter codeine plasma concentrations, resulting in an unpredictable effect such as reduced efficacy or symptoms of opioid withdrawal or prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage adjustment of codeine until stable drug effects are achieved. Discontinuation of quinine could alter codeine plasma concentrations, resulting in an unpredictable effect such as prolonged opioid adverse reactions or decreased opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If quinine is discontinued, monitor the patient carefully and consider adjusting the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Quinine is a moderate inhibitor of CYP3A4 and CYP2D6. CYP3A4 inhibitors may increase codeine-related adverse effects while CYP2D6 inhibitors may reduce efficacy.
Ramelteon: (Moderate) Concomitant use of opioid agonists with ramelteon may cause excessive sedation and somnolence. Avoid prescribing opioid cough medications in patients taking ramelteon. Limit the use of opioid pain medications with ramelteon to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression.
Ramipril: (Moderate) Aspirin, ASA may reduce the vasodilatory efficacy of ACE inhibitors by inhibiting the synthesis of vasodilatory prostaglandins. This interaction has been documented primarily in heart failure patients. However, the established benefits of using aspirin in combination with an ACE inhibitor in patients with ischemic heart disease and left ventricular dysfunction generally outweigh this concern. Patients receiving concurrent salicylates and ACE inhibitor therapy should be monitored for antihypertensive or vasodilatory efficacy; the dose of the ACE inhibitor can be adjusted if indicated based on clinical evaluation.
Ranolazine: (Moderate) Concomitant use of codeine with ranolazine may increase codeine plasma concentrations, but decrease the plasma concentration of the active metabolite, morphine, resulting in reduced efficacy or symptoms of opioid withdrawal. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage increase of codeine until stable drug effects are achieved. Discontinuation of ranolazine could decrease codeine plasma concentrations and increase morphine plasma concentrations resulting in prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. If ranolazine is discontinued, monitor the patient carefully and consider reducing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Ranolazine is a moderate inhibitor of CYP2D6.
Rasagiline: (Contraindicated) Rasagiline is contraindicated for use with codeine due to the risk of serotonin syndrome. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. At least 14 days should elapse between the discontinuation of rasagiline and the initiation of codeine.
Remifentanil: (Major) Concomitant use of remifentanil with carisoprodol may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medications with carisoprodol to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Educate patients about the risks and symptoms of respiratory depression and sedation.
Remimazolam: (Major) Concomitant use of opioid agonists with remimazolam may cause respiratory depression, hypotension, profound sedation, and death. Titrate the dose of remimazolam to the desired clinical response and continuously monitor sedated patients for hypotension, airway obstruction, hypoventilation, apnea, and oxygen desaturation. (Moderate) Concomitant use of skeletal muscle relaxants with benzodiazepines can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take benzodiazepines with another CNS depressant for symptoms of excess sedation.
Repaglinide: (Moderate) Salicylates, by inhibiting prostaglandin E2 synthesis, can indirectly increase insulin secretion. Thus, salicylates can decrease blood sugar and may potentiate the effects of antidiabetic agents. In large doses, salicylates uncouple oxidative phosphorylation, deplete hepatic and muscle glycogen, and cause hyperglycemia and glycosuria. After acute overdose or use of greater than maximum recommended daily dosages, salicylates can cause either hypoglycemia or hyperglycemia. Large doses of aspirin should be used cautiously in patients who receive antidiabetic agents.
Ribociclib: (Moderate) Concomitant use of codeine with ribociclib may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of ribociclib could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If ribociclib is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Ribociclib is a strong inhibitor of CYP3A4.
Ribociclib; Letrozole: (Moderate) Concomitant use of codeine with ribociclib may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of ribociclib could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If ribociclib is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Ribociclib is a strong inhibitor of CYP3A4.
Rifabutin: (Moderate) Concomitant use of codeine with rifabutin can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If rifabutin is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Rifabutin is a moderate CYP3A4 inducer.
Rifampin: (Moderate) Concomitant use of codeine with rifampin can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If rifampin is discontinued, consider a dose reduction of codeine and frequently monitor for signs or respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Rifampin is a strong CYP3A4 inducer. (Minor) Carisoprodol is metabolized via CYP2C19. The formation of meprobamate (active metabolite of carisoprodol) is catalyzed by CYP2C19. If carisoprodol is combined with an inducer of CYP2C19 such as rifampin, the potential exists for increased metabolism of carisoprodol. Theoretically, carisoprodol plasma concentrations could be decreased, and meprobamate (active metabolite) plasma concentrations could be increased. The clinical significance of this interaction is unknown.
Rifapentine: (Moderate) Concomitant use of codeine with rifapentine can decrease codeine levels, resulting in less metabolism by CYP2D6 and decreased morphine concentrations; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor for reduced efficacy of codeine and signs of opioid withdrawal; consider increasing the dose of codeine as needed. If rifapentine is discontinued, consider a dose reduction of codeine and frequently monitor for signs of respiratory depression and sedation. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A4 to norcodeine; norcodeine does not have analgesic properties. Rifapentine is a strong CYP3A4 inducer.
Risedronate: (Minor) Monitor for gastrointestinal adverse events during concurrent use of risedronate and aspirin. Both medications have been associated with gastrointestinal irritation although data suggest concomitant use introduces little additional risk for adverse effects for most patients.
Risperidone: (Moderate) Concomitant use of codeine with other central nervous system (CNS) depressants, such as risperidone, can potentiate the effects of codeine and may lead to additive CNS or respiratory depression, profound sedation, or coma. Prior to concurrent use of codeine in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Consider the patient's use of alcohol or illicit drugs. If these agents are used together, a reduced dosage of codeine and/or the CNS depressant is recommended. Carefully monitor the patient for hypotension, CNS depression, and respiratory depression. Carbon dioxide retention from opioid-induced respiratory depression can exacerbate the sedating effects of opioids.
Ritlecitinib: (Moderate) Concomitant use of codeine with ritlecitinib may increase codeine plasma concentrations, resulting in greater metabolism by CYP2D6, increased morphine concentrations, and prolonged opioid adverse reactions, including hypotension, respiratory depression, profound sedation, coma, and death. It is recommended to avoid this combination when codeine is being used for cough. If coadministration is necessary, monitor patients closely at frequent intervals and consider a dosage reduction of codeine until stable drug effects are achieved. Discontinuation of ritlecitinib could decrease codeine plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to codeine. If ritlecitinib is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Codeine is primarily metabolized by CYP2D6 to morphine, and by CYP3A to norcodeine; norcodeine does not have analgesic properties. Ritlecitinib is a moderate inh

Carisoprodol, Aspirin, Codeine Phosphate/Soma Compound with Codeine Oral Tab: 200-325-16mg

Adults

1,600 mg/day PO carisoprodol, 2,600 mg/day PO aspirin, and 128 mg/day PO codeine (8 tablets/day PO).

Geriatric

1,600 mg/day PO carisoprodol, 2,600 mg/day PO aspirin, and 128 mg/day PO codeine (8 tablets/day PO).

Adolescents

Safety and efficacy have not been established.

Children

12 years: Safety and efficacy have not been established.
1 to 11 years: Use is contraindicated.

Infants

Use is contraindicated.

Aspirin; carisoprodol; codeine is a fixed dose product containing a centrally acting muscle relaxant (carisoprodol), an analgesic with antiinflammatory and antipyretic properties (aspirin), and a centrally acting narcotic analgesic (codeine). The combination provides pain and muscle spasm relief. Clinical studies have shown that combining aspirin and codeine produces a significant additive effect in analgesic efficacy.
 
Aspirin, ASA: Aspirin inhibits cyclo-oxygenase (COX), an enzyme responsible for the conversion of arachidonic acid to prostaglandin G2 (PGG2), the first step in prostaglandin synthesis. In vivo, aspirin is hydrolyzed to salicylic acid and acetate. However, hydrolysis is not required for aspirin activity. Aspirin irreversibly inhibits COX by acetylation of a specific serine moiety. In comparison, salicylic acid has little or no ability to inhibit COX in vitro despite inhibiting prostaglandin synthesis at the site of inflammation in vivo. The exact mechanism of prostaglandin inhibition by salicylic acid is unclear. Aspirin appears to inhibit COX through two pathways and seems to have a different mechanism of action than other salicylates. The antiinflammatory action of aspirin is believed to be a result of peripheral inhibition of COX-1 and COX-2, but aspirin may also inhibit the action and synthesis of other mediators of inflammation. Salicylates are effective in cases where inflammation has caused sensitivity of pain receptors (hyperalgesia). It appears prostaglandins, specifically prostaglandins E and F, are responsible for sensitizing the pain receptors; therefore, salicylates have an indirect analgesic effect by inhibiting the production of further prostaglandins and does not directly affect hyperalgesia or the pain threshold. Other aspirin-mediated activities include GI injury secondary to prostaglandin inhibition, and inhibition of platelet aggregation by irreversible inhibition of prostaglandin cylo-oxygenase.
Carisoprodol: The actions of carisoprodol are related to a central mechanism and not to a direct effect on skeletal muscle. The exact mechanism is not known, but may be related to its sedative properties. The active metabolite of carisoprodol, meprobamate, has anxiolytic and sedative properties; it is unknown to what degree meprobamate affects the safety and efficacy of the combination. In animals, carisoprodol has been shown to produce muscle relaxation by blocking interneuronal activity and depressing transmission of polysynaptic neurons in the spinal cord and in the descending reticular formation of the brain.
Codeine: Codeine is a weak mu-opiate receptor agonist and the majority of its analgesic effect is due to metabolism to morphine. Opiate analgesia is mediated through changes in the perception of pain at the spinal cord and higher levels in the CNS. Opiate analgesics also alter the emotional response to pain. The stimulatory effects of opioids are the result of 'disinhibition' as the release of inhibitory neurotransmitters such as GABA and acetylcholine is blocked. Other opioid-mediated activities include depression of the respiratory center at the brainstem, cough suppression at the cough center in the medulla, decreased gastric, biliary, and pancreatic secretions, delayed GI motility, stimulation of chemoreceptor trigger zone resulting in nausea and vomiting, peripheral vasodilation, histamine release, and increased bladder detrusor muscle tone.

Aspirin; carisoprodol; codeine combination is administered orally. The pharmacokinetics of this drug combination have not been studied. The systemic pharmacokinetic information below is based on administration of each agent alone.
Carisoprodol: Carisoprodol distributes widely in the body; it crosses the placenta and is distributed into breast milk. Carisoprodol is hepatically metabolized to several metabolites, including meprobamate, via the cytochrome isoenzyme CYP2C19. After a single dose administration of 350mg, the plasma half-life of carisoprodol is about 2 hours and the plasma half-life of meprobamate is about 10 hours. Excretion is mainly via the urine as metabolites.
Aspirin, ASA: Aspirin is hydrolyzed to salicylic acid by the liver. Salicylic acid is widely distributed into most body tissues including CNS, breast milk, and fetal tissues. Aspirin is bound to plasma proteins in a concentration dependent fashion; use in patients already receiving other highly protein-bound drugs may increase free-drug and thus effect. Aspirin is 99% metabolized to salicylic acid and other metabolites. The elimination half-life of aspirin in plasma is about 15 minutes. Salicylic acid, but not aspirin itself, undergoes saturable kinetics. At low doses, the elimination is first-order and the half-life remains constant at 2 to 3 hours; however, at higher doses, the enzymes responsible for metabolism become saturated and the apparent half-life can increase to over 20 hours. Because of this, 5 to 7 days may be required before a steady-state concentration is reached. Salicylic acid and its metabolites are excreted primarily by the kidneys. The clearance of free salicylic acid is enhanced by alkalinization of the urine from less than 5% at normal pH to more than 80% at pH more than 6.5.
Codeine: After absorption codeine distributes widely from the intravascular spaces to the tissues; it is found in CNS, breast milk, and fetal tissue. The plasma concentration of codeine does not correlate with brain concentration of codeine or the relief of pain. The metabolism to morphine is mediated by CYP2D6. Patients with altered CYP2D6 activity may not experience the expected analgesic response to codeine (low-activity) or may have higher than expected serum morphine concentrations after codeine administration. The plasma half-life is approximately 2.9 hours with 90% renal elimination of codeine and metabolites within 24 hours of oral dosing.

Oral Route

Carisoprodol: The absolute bioavailability of carisoprodol has not been determined, but the time to peak concentrations is 1.5 to 2 hours. Administration of carisoprodol 350 mg orally with a high-fat meal had no effect on drug pharmacokinetics.
Aspirin, ASA: The rate of aspirin absorption from the gastrointestinal (GI) tract is dependent upon the presence or absence of food, gastric pH (the presence of absence of GI antacids), and other physiologic factors.
Codeine: Codeine is readily absorbed from the GI tract. At therapeutic doses, the analgesic effect reaches a peak within 2 hours and persists between 4 and 6 hours.

Pregnancy

Avoid aspirin use during the third trimester of pregnancy (starting at 30 weeks of gestation) due to the risk of premature closure of the fetal ductus arteriosus and persistent pulmonary hypertension in the neonate. If NSAID treatment is deemed necessary between 20 to 30 weeks of pregnancy, limit use to the lowest effective dose and shortest duration possible. Consider ultrasound monitoring of amniotic fluid if NSAID treatment extends beyond 48 hours. Discontinue the NSAID if oligohydramnios occurs and follow up according to clinical practice. These recommendations do not apply to low-dose 81 mg aspirin prescribed for certain conditions in pregnancy. Use of NSAIDs around 20 weeks gestation or later in pregnancy may cause fetal renal dysfunction leading to oligohydramnios, and in some cases, neonatal renal impairment. These adverse outcomes are seen, on average, after days to weeks of treatment, although oligohydramnios has been infrequently reported as soon as 48 hours after NSAID initiation. Oligohydramnios is often, but not always, reversible with treatment discontinuation. Complications of prolonged oligohydramnios may include limb contractures and delayed lung maturation. In some postmarketing cases of impaired neonatal renal function, invasive procedures such as exchange transfusion or dialysis were required. Salicylates have also been associated with alterations in maternal and neonatal hemostasis mechanisms, decreased birth weight, and perinatal mortality. Avoid aspirin 1 week prior to and during labor and obstetric delivery because it can result in excessive blood loss at delivery. Prolonged gestation and labor due to prostaglandin inhibition have been reported. Data over many decades of carisoprodol use in pregnancy have not identified a drug-associated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes. Data on meprobamate, the primary metabolite of carisoprodol, also do not show a consistent association between maternal use of meprobamate and an increased risk of major birth defects. Codeine is not recommended for use during and immediately before labor when other analgesic techniques are more appropriate. Opioids can prolong labor and obstetric delivery by temporarily reducing the strength, duration, and frequency of uterine contractions. This effect is not consistent and may be offset by an increased rate of cervical dilatation, which may shorten labor. Opioids cross the placenta and may produce respiratory depression and psycho-physiologic effects in the neonate. An opioid antagonist (e.g., naloxone) should be available for reversal of opioid-induced respiratory depression in the neonate. Further, prolonged maternal use of opioids during pregnancy may result in neonatal opioid withdrawal syndrome (NOWS). Monitor the exposed neonate for withdrawal symptoms, including irritability, hyperactivity and abnormal sleep pattern, high-pitched cry, tremor, vomiting, diarrhea, and failure to gain weight, and manage accordingly. Onset, duration, and severity of opioid withdrawal may vary based on the specific opioid used, duration of use, timing and amount of last maternal use, and rate of elimination by the newborn. [55881] Guidelines recommend early universal screening of pregnant patients for opioid use and opioid use disorder at the first prenatal visit. Obtain a thorough history of substance use and review the Prescription Drug Monitoring Program to determine if patients have received prior prescriptions for opioids or other high-risk drugs such as benzodiazepines. Discuss the risks and benefits of opioid use during pregnancy, including the risk of becoming physiologically dependent on opioids, the possibility for NOWS, and how long-term opioid use may affect care during a future pregnancy.[64838] [64909] In women undergoing uncomplicated normal spontaneous vaginal birth, consider opioid therapy only if expected benefits for both pain and function are anticipated to outweigh risks to the patient. If opioids are used, use in combination with nonpharmacologic therapy and nonopioid pharmacologic therapy, as appropriate. Use immediate-release opioids instead of extended-release or long-acting opioids; order the lowest effective dosage and prescribe no greater quantity of opioids than needed for the expected duration of such pain severe enough to require opioids.[64909] For women using opioids for chronic pain, consider strategies to avoid or minimize the use of opioids, including alternative pain therapies (i.e., nonpharmacologic) and nonopioid pharmacologic treatments. Opioid agonist pharmacotherapy (e.g., methadone or buprenorphine) is preferable to medically supervised withdrawal in pregnant women with opioid use disorder.[64838]