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    Opioid Agonists and Other Drug Combinations

    BOXED WARNING

    Accidental exposure, asthma, chronic obstructive pulmonary disease (COPD), coadministration with other CNS depressants, cor pulmonale, hypoxemia, obesity, pulmonary disease, respiratory depression, respiratory insufficiency, scoliosis, sleep apnea, status asthmaticus

    As with other opiate agonists, products containing oxycodone should be avoided in patients with severe pulmonary disease. Additionally, avoid coadministration with other CNS depressants unless no other alternatives are available, as this significantly increases the risk for respiratory depression, low blood pressure, and death. Acetaminophen; oxycodone use is contraindicated in patients with significant respiratory depression, and in patients with acute or severe asthma (e.g., status asthmaticus) or hypercarbia in unmonitored care settings or in the absence of resuscitative equipment. Receipt of moderate oxycodone doses in these patients may significantly decrease pulmonary ventilation. In patients with chronic obstructive pulmonary disease (COPD), cor pulmonale, decreased respiratory reserve, hypoxia, hypercapnia, respiratory insufficiency, upper airway obstruction, or preexisting respiratory depression, it is recommended that non-opioid analgesics be considered as alternatives to acetaminophen; oxycodone, as even usual therapeutic doses of oxycodone may decrease respiratory drive and cause apnea in these patient populations. Extreme caution should also be used in patients with chronic asthma, kyphoscoliosis (a type of scoliosis), hypoxemia, or paralysis of the phrenic nerve. Patients with advanced age, debilitation, or sleep apnea are at an increased risk for the development of respiratory depression associated with oxycodone. Use with caution in patients with obesity as this is a risk factor for obstructive sleep apnea syndrome and/or decreased respiratory reserve. Respiratory depression, if left untreated, may cause respiratory arrest and death. Carbon dioxide retention from respiratory depression may also worsen opioid sedating effects. Due to the risk of serious respiratory depression, the extended-release tablets should be reserved for patients in whom alternative treatment options (e.g., non-opioid analgesics) are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain. Do not use extended-release tablets on an as needed basis. Proper dosing and titration are essential; patients should be monitored for respiratory depression, particularly during the first 24—72 hours after therapy initiation or after a dose increase. Patients must be instructed to keep acetaminophen; oxycodone away from pediatric patients and others for whom the drug was not prescribed, as accidental exposure or improper use may lead to fatal respiratory depression. Management of respiratory depression should include observation, necessary supportive measures, and opioid antagonist use when indicated.

    Substance abuse

    Oxycodone is a strong opiate agonist; therefore, acetaminophen; oxycodone is subject to substance abuse and psychologic dependence. Addiction may occur in patients appropriately prescribed oxycodone. Patients with a previous history of substance abuse may be at increased risk of relapse if treated with acetaminophen; oxycodone. Also, patients with mental illness (e.g., major depression) or a family history of substance abuse or alcoholism may be at greater risk. Monitor patients for signs of misuse, abuse, or addiction. Abuse or misuse of the extended-release tablets by crushing, chewing, snorting, or injecting the dissolved product will lead to uncontrolled drug delivery that may be fatal. Health care professionals should not let concerns over psychologic dependence deter them from using adequate amounts of opiate agonists in the management of severe pain.

    Labor, neonatal opioid withdrawal syndrome, obstetric delivery, pregnancy

    Acetaminophen; oxycodone is classified as FDA pregnancy risk category C. No well-controlled studies in pregnant women have been performed. Some experts suggest increased risk of oxycodone if used for prolonged periods or at high doses near term. Chronic maternal use of opioids during pregnancy may result in neonatal opioid withdrawal syndrome. This syndrome can be life-threatening and includes symptoms such as poor feeding, irritability, hyperactivity and abnormal sleep pattern, high pitched cry, tremor, vomiting, diarrhea, rigidity, and seizures. Neonates whose mothers have been taking oxycodone chronically may show some respiratory depression and/or withdrawal symptoms at birth or within a few days. Neonatal opioid withdrawal syndrome may be life-threatening and should be treated according to protocols developed by neonatology experts. Acetaminophen; oxycodone should not be used immediately prior to or during labor or obstetric delivery due to the potential for respiratory depression in the newborn. No overall increase in fetal mortality, as determined by pregnancy outcomes of mothers that overdosed on various amounts of acetaminophen, was apparent amongst 300 women. Treatment with acetylcysteine or methionine did not appear to affect fetal or neonatal toxicity. Of 235 babies exposed to an overdose of only acetaminophen, 168 were normal, 8 had malformations, 16 were spontaneously aborted, and 43 were electively terminated. Of 67 babies exposed to an overdose of a combination acetaminophen product, 51 were normal, 3 had malformations, 2 were spontaneously aborted (late fetal deaths), and 11 were electively terminated. None of the babies with malformations were exposed during the first trimester, but all of the spontaneous abortions and one of the late fetal deaths were subsequent to first trimester exposure.

    Alcoholism, hepatic disease, hepatitis, hepatotoxicity, potential for overdose or poisoning

    Acetaminophen has the potential for overdose or poisoning that can cause acute hepatic failure, at times resulting in liver transplantation or death. Most cases of hepatotoxicity are a result of exceeding maximum daily dosage limits and often involve the use of more than one acetaminophen-containing product. Acetaminophen; oxycodone should be used with caution in patients with alcoholism, chronic malnutrition, active hepatitis, or severe hypovolemia, as these patients may be at increased risk for acetaminophen-induced hepatotoxicity. In patients with chronic hepatic disease, acetaminophen can be used safely and is often preferred to nonsteroidal anti-inflammatory drugs (NSAIDs) due to the absence of platelet impairment, gastrointestinal toxicity, and nephrotoxicity. Though the half-life of acetaminophen may be prolonged, repeated dosing does not result in drug or metabolite accumulation. In addition, cytochrome P450 activity is not increased and glutathione stores are not depleted in hepatically impaired patients taking therapeutic doses, therefore toxic metabolite formation and accumulation is not altered. Although it is always prudent to use the smallest dose of acetaminophen for the shortest duration necessary, courses less than 2 weeks in length have been administered safely to adult patients with stable chronic liver disease. In patients without pre-existing hepatic impairment, hepatotoxicity may occur if the total daily dose exceeds 4000 mg/day or more than 3 alcoholic beverages per day are consumed while taking acetaminophen. Patients and caregivers should be appropriately counseled on acetaminophen intake and reminded that all acetaminophen-containing prescription and over-the-counter products, both single-entity and combination, must be considered in the total daily dosage. Oxycodone may accumulate leading to a prolonged duration of action in patients with decreased liver function. Close monitoring is warranted to avoid respiratory depression. Guidelines for use of the extended-release tablets in patients with hepatic impairment recommend initiating treatment at 50% of the normal starting dosage.

    DEA CLASS

    Rx, schedule II

    DESCRIPTION

    Combination product to treat moderate to severe pain. Acetaminophen is a non-salicylate analgesic; oxycodone is an oral semisynthetic opiate agonist. The combination produces additive analgesia as compared to either agent alone.

    COMMON BRAND NAMES

    Endocet, Percocet, Primlev, Roxicet, XARTEMIS XR

    HOW SUPPLIED

    Endocet/Oxycodone Hydrochloride, Acetaminophen/Oxycodone, Acetaminophen/Percocet/Primlev/Roxicet Oral Tab: 10-300mg, 10-325mg, 2.5-325mg, 5-300mg, 5-325mg, 7.5-300mg, 7.5-325mg
    Oxycodone Hydrochloride, Acetaminophen/Oxycodone, Acetaminophen/Roxicet Oral Sol: 5mL, 5-325mg

    DOSAGE & INDICATIONS

    For the treatment of moderate pain to moderately-severe pain.
    For the treatment of acute pain severe enough to require opioid treatment and for which alternative treatment options (e.g., non-opioid analgesics) are inadequate.
    Oral dosage (extended-release tablets, Xartemis XR)
    Adults

    2 tablets PO every 12 hours administered with or without food. A second dose of 2 tablets may be given as early as 8 hours after the initial dose if needed for analgesia at that time. Subsequent doses are to be administered every 12 hours. Individualize the dosage regimen, considering prior analgesic exposure and risk for abuse. Monitor patients closely for excessive sedation and respiratory depression, particularly in the first 24—72 hours of treatment. To discontinue, use a gradual downward titration of 50% every 2—4 days to prevent withdrawal in the physically dependent patient. Extended-release tablets are NOT interchangeable with other acetaminophen; oxycodone products.

    Oral dosage (immediate-release tablets or capsules)
    Adults

    1—2 tablets or capsules (2.5—10 mg of oxycodone) PO every 6 hours as needed. It may be necessary to exceed the usual dosage recommendation (i.e., give every 4 hours) in cases of severe pain or in those patients who have become tolerant to the analgesic effect of opiate agonists. Maximum acetaminophen dose is 4 g/day.

    Oral dosage (liquid)
    Adults

    5—10 ml (5—10 mg of oxycodone) PO every 6 hours as needed. It may be necessary to exceed the usual dosage recommendation (i.e., give every 4 hours) in cases of severe pain or in those patients who have become tolerant to the analgesic effect of opiate agonists. Maximum acetaminophen dose is 4 g/day.

    Children†

    0.05—0.15 mg oxycodone/kg PO every 6 hours as needed. May titrate up to 5 mg oxycodone PO every 4—6 hours. The maximum acetaminophen dose is 75 mg/kg/day.

    MAXIMUM DOSAGE

    Adults

    Immediate-release formulations: Acetaminophen 4 g/day PO; the maximum dose of the acetaminophen; oxycodone combination is limited by the total daily limit of acetaminophen.
    Extended-release tablets: 4 tablets/day PO. Total daily dose of acetaminophen from all products should not exceed 4 g/day PO.

    Geriatric

    Immediate-release formulations: Acetaminophen 4 g/day PO; the maximum dose of the acetaminophen; oxycodone combination is limited by the total daily limit of acetaminophen.
    Extended-release tablets: 4 tablets/day PO. Total daily dose of acetaminophen from all products should not exceed 4 g/day PO.

    Adolescents

    Immediate-release formulations: Safety and efficacy have not been established. Doses containing up to acetaminophen 4 g/day PO have been used. The maximum dose of the acetaminophen; oxycodone combination is limited by the total daily limit of acetaminophen.
    Extended-release tablets: Safety and efficacy have not been established.

    Children

    Immediate-release formulations: Safety and efficacy have not been established. Doses up to acetaminophen 75 mg/kg/day PO or 4 g/day PO, whichever is less, have been used. The maximum dose of the acetaminophen; oxycodone combination is limited by the total daily limit of acetaminophen.
    Extended-release tablets: Safety and efficacy have not been established.

    Infants

    Safety and efficacy have not been established.

    Neonates

    Safety and efficacy have not been established.

    DOSING CONSIDERATIONS

    Hepatic Impairment

    Dosage should be modified depending upon the clinical response and degree of hepatic impairment. For initiation of the extended-release tablets, give 1 tablet and adjust dosage as needed.

    Renal Impairment

    Dosage should be modified depending upon the clinical response and degree of renal impairment. For initiation of the extended-release tablets, give 1 tablet and adjust dosage as needed.

    ADMINISTRATION

    Oral Administration

    Immediate-release formulations:
    Administer with a full glass of water. May be taken food or milk to minimize GI irritation.
    Extended-release tablets:
    Swallow whole, 1 tablet at a time, with enough water to ensure complete swallowing immediately after placing in mouth.
    May be given with or without food.
    Do not break, chew, crush, cut, dissolve, or split the tablets due to the risk of uncontrolled drug delivery.

    STORAGE

    Generic:
    - Store at controlled room temperature (between 68 and 77 degrees F)
    Endocet:
    - Protect from moisture
    - Store at controlled room temperature (between 68 and 77 degrees F)
    Magnacet:
    - Store at controlled room temperature (between 68 and 77 degrees F)
    Narvox:
    - Store at controlled room temperature (between 68 and 77 degrees F)
    Percocet:
    - Protect from moisture
    - Store at controlled room temperature (between 68 and 77 degrees F)
    Perloxx:
    - Protect from light
    - Store at controlled room temperature (between 68 and 77 degrees F)
    Primalev:
    - Store at controlled room temperature (between 68 and 77 degrees F)
    Primlev:
    - Store at controlled room temperature (between 68 and 77 degrees F)
    Roxicet:
    - Protect from moisture
    - Store at controlled room temperature (between 68 and 77 degrees F)
    Tylox:
    - Protect from moisture
    - Store at room temperature (between 59 to 86 degrees F)
    XARTEMIS XR:
    - Store at 77 degrees F; excursions permitted to 59-86 degrees F
    Xolox:
    - Store at controlled room temperature (between 68 and 77 degrees F)

    CONTRAINDICATIONS / PRECAUTIONS

    General Information

    NOTE: This monograph discusses the contraindications/precautions of acetaminophen; oxycodone combination products. Clinicians may wish to consult the individual monographs for more information about each agent.

    Acetaminophen hypersensitivity, opiate agonist hypersensitivity, sulfite hypersensitivity

    Acetaminophen; oxycodone combinations are contraindicated in patients with known acetaminophen hypersensitivity, oxycodone hypersensitivity, or opiate agonist hypersensitivity.   Acetaminophen hypersensitivity reactions are rare, but severe sensitivity reactions are possible. Although true opiate agonist hypersensitivity is rare, patients who have demonstrated a prior hypersensitivity reaction to oxycodone should not receive other opioid agonists of the phenanthrene subclass including morphine, codeine, and hydromorphone. Use with caution in patients with sulfite hypersensitivity, as some acetaminophen; oxycodone capsules contain sodium metabisulfite and some tablet dosage formulations may as well. Sulfite may cause allergic-type reactions including anaphylactic symptoms and life-threatening or less severe asthmatic episodes in certain susceptible people. The overall prevalence of sulfite sensitivity in the general population is unknown and probably low. Sulfite sensitivity is seen more frequently in asthmatic than in non-asthmatic people.

    Acute abdomen, constipation, dysphagia, esophageal stricture, GI disease, GI obstruction, ileus, inflammatory bowel disease, ulcerative colitis

    Oxycodone is contraindicated in patients who have or are suspected of having paralytic ileus. Due to the effects of opiate agonists on the gastrointestinal tract, all forms of acetaminophen; oxycodone should be used cautiously in patients with GI disease including GI obstruction, ulcerative colitis, or pre-existing constipation. Patients with ulcerative colitis or other inflammatory bowel disease may be more sensitive to constipation caused by opiate agonists. Opiate agonists may obscure the diagnosis or clinical course in patients with an acute abdomen. The extended-release tablets may swell and become sticky when exposed to liquids such as saliva; consider the use of an alternative analgesic in patients with pre-existing esophageal stricture or dysphagia. Do not pre-soak, lick, or wet the extended-release tablet prior to ingestion, or give via feeding tubes as it may cause obstruction.

    Accidental exposure, asthma, chronic obstructive pulmonary disease (COPD), coadministration with other CNS depressants, cor pulmonale, hypoxemia, obesity, pulmonary disease, respiratory depression, respiratory insufficiency, scoliosis, sleep apnea, status asthmaticus

    As with other opiate agonists, products containing oxycodone should be avoided in patients with severe pulmonary disease. Additionally, avoid coadministration with other CNS depressants unless no other alternatives are available, as this significantly increases the risk for respiratory depression, low blood pressure, and death. Acetaminophen; oxycodone use is contraindicated in patients with significant respiratory depression, and in patients with acute or severe asthma (e.g., status asthmaticus) or hypercarbia in unmonitored care settings or in the absence of resuscitative equipment. Receipt of moderate oxycodone doses in these patients may significantly decrease pulmonary ventilation. In patients with chronic obstructive pulmonary disease (COPD), cor pulmonale, decreased respiratory reserve, hypoxia, hypercapnia, respiratory insufficiency, upper airway obstruction, or preexisting respiratory depression, it is recommended that non-opioid analgesics be considered as alternatives to acetaminophen; oxycodone, as even usual therapeutic doses of oxycodone may decrease respiratory drive and cause apnea in these patient populations. Extreme caution should also be used in patients with chronic asthma, kyphoscoliosis (a type of scoliosis), hypoxemia, or paralysis of the phrenic nerve. Patients with advanced age, debilitation, or sleep apnea are at an increased risk for the development of respiratory depression associated with oxycodone. Use with caution in patients with obesity as this is a risk factor for obstructive sleep apnea syndrome and/or decreased respiratory reserve. Respiratory depression, if left untreated, may cause respiratory arrest and death. Carbon dioxide retention from respiratory depression may also worsen opioid sedating effects. Due to the risk of serious respiratory depression, the extended-release tablets should be reserved for patients in whom alternative treatment options (e.g., non-opioid analgesics) are ineffective, not tolerated, or would be otherwise inadequate to provide sufficient management of pain. Do not use extended-release tablets on an as needed basis. Proper dosing and titration are essential; patients should be monitored for respiratory depression, particularly during the first 24—72 hours after therapy initiation or after a dose increase. Patients must be instructed to keep acetaminophen; oxycodone away from pediatric patients and others for whom the drug was not prescribed, as accidental exposure or improper use may lead to fatal respiratory depression. Management of respiratory depression should include observation, necessary supportive measures, and opioid antagonist use when indicated.

    Abrupt discontinuation

    Abrupt discontinuation of prolonged oxycodone therapy can result in withdrawal symptoms. Patients who have been taking acetaminophen; oxycodone regularly and may be physically dependent should be gradually tapered off the medication to avoid a withdrawal reaction. A downward titration of 50% of the dose every 2—4 days may be used in patients taking the extended-release tablets.

    Substance abuse

    Oxycodone is a strong opiate agonist; therefore, acetaminophen; oxycodone is subject to substance abuse and psychologic dependence. Addiction may occur in patients appropriately prescribed oxycodone. Patients with a previous history of substance abuse may be at increased risk of relapse if treated with acetaminophen; oxycodone. Also, patients with mental illness (e.g., major depression) or a family history of substance abuse or alcoholism may be at greater risk. Monitor patients for signs of misuse, abuse, or addiction. Abuse or misuse of the extended-release tablets by crushing, chewing, snorting, or injecting the dissolved product will lead to uncontrolled drug delivery that may be fatal. Health care professionals should not let concerns over psychologic dependence deter them from using adequate amounts of opiate agonists in the management of severe pain.

    CNS depression, head trauma, increased intracranial pressure, intracranial mass, psychosis

    Use acetaminophen; oxycodone with caution in patients with CNS depression, toxic psychosis, head trauma, intracranial mass, or increased intracranial pressure. Opioids may aggravate these conditions and alter neurologic parameters (e.g., level of consciousness, pupillary responses). Oxycodone-induced hypoventilation can produce cerebral hypoxia, carbon dioxide retention, and raise cerebrospinal fluid pressure. Monitor for signs of drowsiness or depressed respirations.

    Cardiac arrhythmias, cardiac disease, hypotension, hypovolemia, orthostatic hypotension

    Use acetaminophen; oxycodone with caution in patients with cardiac disease, cardiac arrhythmias, hypotension, orthostatic hypotension, or hypovolemia. Opiate agonists, such as oxycodone, induce histamine release and produce cholinergic side effects like bradycardia, peripheral vasodilation, and hypotension. These effects may produce severe hypotension in patients whose ability to maintain blood pressure has been compromised by a depleted blood volume. Orthostatic hypotension may occur.

    Labor, neonatal opioid withdrawal syndrome, obstetric delivery, pregnancy

    Acetaminophen; oxycodone is classified as FDA pregnancy risk category C. No well-controlled studies in pregnant women have been performed. Some experts suggest increased risk of oxycodone if used for prolonged periods or at high doses near term. Chronic maternal use of opioids during pregnancy may result in neonatal opioid withdrawal syndrome. This syndrome can be life-threatening and includes symptoms such as poor feeding, irritability, hyperactivity and abnormal sleep pattern, high pitched cry, tremor, vomiting, diarrhea, rigidity, and seizures. Neonates whose mothers have been taking oxycodone chronically may show some respiratory depression and/or withdrawal symptoms at birth or within a few days. Neonatal opioid withdrawal syndrome may be life-threatening and should be treated according to protocols developed by neonatology experts. Acetaminophen; oxycodone should not be used immediately prior to or during labor or obstetric delivery due to the potential for respiratory depression in the newborn. No overall increase in fetal mortality, as determined by pregnancy outcomes of mothers that overdosed on various amounts of acetaminophen, was apparent amongst 300 women. Treatment with acetylcysteine or methionine did not appear to affect fetal or neonatal toxicity. Of 235 babies exposed to an overdose of only acetaminophen, 168 were normal, 8 had malformations, 16 were spontaneously aborted, and 43 were electively terminated. Of 67 babies exposed to an overdose of a combination acetaminophen product, 51 were normal, 3 had malformations, 2 were spontaneously aborted (late fetal deaths), and 11 were electively terminated. None of the babies with malformations were exposed during the first trimester, but all of the spontaneous abortions and one of the late fetal deaths were subsequent to first trimester exposure.

    Breast-feeding

    Use caution when prescribing acetaminophen; oxycodone for mothers of breast-feeding infants. According to the manufacturer, oxycodone and acetaminophen are both distributed into breast milk, and acetaminophen; oxycodone generally should not be used by breast-feeding mothers because of the possibility of sedation and/or respiratory depression in the baby. A retrospective study compared central nervous system (CNS) depression in breast-feeing infants of mothers receiving oxycodone (n = 139), codeine (n = 210), or acetaminophen (n = 184). Symptoms of CNS depression were determined through questionnaires to the mothers. CNS depression was significantly higher in breast-fed infants exposed to oxycodone compared to acetaminophen (20.1% vs 0.5%, p < 0.0001) and was not significantly different compared to infants exposed to codeine (16.7%, p > 0.05). The doses of both oxycodone and codeine in the mothers with infants that experienced symptoms were significantly higher compared to those that did not (oxycodone median 0.4 mg/kg/day vs 0.15 mg/kg/day, p = 0.0005; codeine median 1.4 mg/kg/day vs 0.9 mg/kg/day, p < 0.001). As with all opioid-containing products, if acetaminophen; oxycodone is used by a breast-feeding mother, the infant should be monitored for sedation, respiratory depression, and changes in feeding patterns. According to the American Academy of Pediatrics (AAP), acetaminophen as maternal monotherapy has not been associated with any observable changes in nursing infants. The AAP regards acetaminophen as a maternal medicine that is usually compatible with breast feeding. Other alternative analgesics considered to be usually compatible with breast-feeding by the AAP include ibuprofen and morphine; the AAP has not evaluated the use of oxycodone in breast-feeding women. Acetaminophen; oxycodone should not be used chronically during breast-feeding as withdrawal symptoms may occur in the infant when the mother stops chronic oxycodone therapy.

    Bladder obstruction, oliguria, prostatic hypertrophy, renal disease, renal impairment, urethral stricture, urinary retention

    Acetaminophen; oxycodone should be used cautiously in patients with renal impairment or renal failure; dosage adjustments may be required. Oxycodone can cause urinary retention and oliguria, due to increasing the tension of the detrusor muscle. Patients more prone to these effects include those with prostatic hypertrophy, urethral stricture, bladder obstruction or pelvic tumors. In addition, oxycodone may accumulate in these patients leading to a prolonged duration of action and potential increase in side effects. Chronic acetaminophen administration should be avoided in patients with underlying renal disease; however it may be used for episodic pain.

    Alcoholism, hepatic disease, hepatitis, hepatotoxicity, potential for overdose or poisoning

    Acetaminophen has the potential for overdose or poisoning that can cause acute hepatic failure, at times resulting in liver transplantation or death. Most cases of hepatotoxicity are a result of exceeding maximum daily dosage limits and often involve the use of more than one acetaminophen-containing product. Acetaminophen; oxycodone should be used with caution in patients with alcoholism, chronic malnutrition, active hepatitis, or severe hypovolemia, as these patients may be at increased risk for acetaminophen-induced hepatotoxicity. In patients with chronic hepatic disease, acetaminophen can be used safely and is often preferred to nonsteroidal anti-inflammatory drugs (NSAIDs) due to the absence of platelet impairment, gastrointestinal toxicity, and nephrotoxicity. Though the half-life of acetaminophen may be prolonged, repeated dosing does not result in drug or metabolite accumulation. In addition, cytochrome P450 activity is not increased and glutathione stores are not depleted in hepatically impaired patients taking therapeutic doses, therefore toxic metabolite formation and accumulation is not altered. Although it is always prudent to use the smallest dose of acetaminophen for the shortest duration necessary, courses less than 2 weeks in length have been administered safely to adult patients with stable chronic liver disease. In patients without pre-existing hepatic impairment, hepatotoxicity may occur if the total daily dose exceeds 4000 mg/day or more than 3 alcoholic beverages per day are consumed while taking acetaminophen. Patients and caregivers should be appropriately counseled on acetaminophen intake and reminded that all acetaminophen-containing prescription and over-the-counter products, both single-entity and combination, must be considered in the total daily dosage. Oxycodone may accumulate leading to a prolonged duration of action in patients with decreased liver function. Close monitoring is warranted to avoid respiratory depression. Guidelines for use of the extended-release tablets in patients with hepatic impairment recommend initiating treatment at 50% of the normal starting dosage.

    Geriatric

    Geriatric and debilitated patients are at particular risk for respiratory depression when given large initial doses of oxycodone or when oxycodone is given in conjunction with other agents that depress respiration. Special precaution should be given when determining the dosing amount and frequency of dosing for geriatric patients, since clearance of oxycodone may be slightly reduced in this patient population when compared to younger adults. Monitor patients taking acetaminophen; oxycodone closely, particularly at treatment initiation, with dose titration, or when the drug is given concurrently with other drugs that depress respiration. According to the Beers Criteria, opiate agonists are considered potentially inappropriate medications (PIMs) in geriatric patients with a history of falls or fractures and should be avoided in these populations, with the exception of pain management due to recent fractures or joint replacement, since opiates can produce ataxia, impaired psychomotor function, syncope, and additional falls. If an opiate must be used, consider reducing use of other CNS-active medications that increase the risk of falls and fractures and implement other strategies to reduce fall risk.

    Children, infants, neonates

    Acetaminophen; oxycodone is used in pediatric patients with moderate to severe pain in clinical practice; however, safety and efficacy have not been established in neonates, infants, children, or adolescents.   Consider pediatric-specific precautions before use. Neonates and infants < 6 months of age have highly variable clearance of opiate agonists. Therefore, infants younger than 6 months of age may be given opiate agonists but must be closely monitored for apnea until 24 hours after their last dose. Clinical practice guidelines suggest close monitoring of children up to 1 year of age.

    G6PD deficiency

    Patients with G6PD deficiency who overdose with acetaminophen may be at increased risk for drug-induced hemolysis. Practitioners should be aware of this potential complication and monitor at-risk patients for signs and symptoms of hemolysis while taking acetaminophen; oxycodone. Conflicting data exists on whether therapeutic doses of acetaminophen can cause hemolysis in G6PD deficient patients. However, a direct cause and effect relationship has not been well established, and therefore, therapeutic doses are generally considered safe in this population.

    Bone marrow suppression, immunosuppression, infection

    Symptoms of acute infection (e.g., fever, pain) can be masked during treatment with acetaminophen; oxycodone in patients who have bone marrow suppression or immunosuppression.

    Driving or operating machinery

    Any patient receiving acetaminophen; oxycodone should be warned about the possibility of sedation and to use caution when driving or operating machinery.

    Biliary tract disease, pancreatitis

    Oxycodone can increase the tone of the biliary tract causing spasms, especially in the sphincter of Oddi. Acetaminophen; oxycodone should be used cautiously in patients with biliary tract disease or acute pancreatitis. Biliary effects of opioids may result in elevations of plasma amylase concentration.

    Adrenal insufficiency, hypothyroidism, myxedema

    Use acetaminophen; oxycodone with caution in patients with adrenal insufficiency (i.e., Addison's disease), hypothyroidism, or myxedema. Such patients may be at increased risk of adverse events. Opioids inhibit the secretion of adrenocorticotropic hormone (ACTH), cortisol, and luteinizing hormone (LH); however, the thyroid stimulating hormone may be either stimulated or inhibited by opioids. Rarely, adrenal insufficiency has been reported in association with opioid use. Patients should seek immediate medical attention if they experience symptoms such as nausea, vomiting, loss of appetite, fatigue, weakness, dizziness, or hypotension. If adrenocortical insufficiency is suspected, confirm with diagnostic testing as soon as possible. If diagnosed, the patient should be treated with physiologic replacement doses of corticosteroids, and if appropriate, weaned off of opioid therapy. If the opioid can be discontinued, a follow-up assessment of adrenal function should be performed to determine if corticosteroid treatment can be discontinued. Other opioids may be tried; some cases reported use of a different opioid with no recurrence of adrenocortical insufficiency. It is unclear which, if any, opioids are more likely to cause adrenocortical insufficiency. In addition, chronic opioid use may lead to symptoms of hypogonadism, resulting from changes in the hypothalamic-pituitary-gonadal axis. Monitor patients for symptoms of opioid-induced endocrinopathy, particularly those receiving a daily dose equivalent to 100 mg or more of morphine. Patients presenting with signs or symptoms of androgen deficiency should undergo laboratory evaluation.

    ADVERSE REACTIONS

    Severe

    oliguria / Early / 0-1.0
    neonatal abstinence syndrome / Early / Incidence not known
    cerebral edema / Early / Incidence not known
    seizures / Delayed / Incidence not known
    suicidal ideation / Delayed / Incidence not known
    respiratory arrest / Rapid / Incidence not known
    pulmonary edema / Early / Incidence not known
    apnea / Delayed / Incidence not known
    GI obstruction / Delayed / Incidence not known
    ileus / Delayed / Incidence not known
    pancreatitis / Delayed / Incidence not known
    hepatic necrosis / Delayed / Incidence not known
    hepatic failure / Delayed / Incidence not known
    proteinuria / Delayed / Incidence not known
    interstitial nephritis / Delayed / Incidence not known
    renal papillary necrosis / Delayed / Incidence not known
    renal tubular necrosis / Delayed / Incidence not known
    renal failure (unspecified) / Delayed / Incidence not known
    agranulocytosis / Delayed / Incidence not known
    hemolytic anemia / Delayed / Incidence not known
    pancytopenia / Delayed / Incidence not known
    angioedema / Rapid / Incidence not known
    anaphylactoid reactions / Rapid / Incidence not known
    Stevens-Johnson syndrome / Delayed / Incidence not known
    acute generalized exanthematous pustulosis (AGEP) / Delayed / Incidence not known
    laryngeal edema / Rapid / Incidence not known
    toxic epidermal necrolysis / Delayed / Incidence not known
    anaphylactic shock / Rapid / Incidence not known
    cardiac arrest / Early / Incidence not known
    bradycardia / Rapid / Incidence not known
    visual impairment / Early / Incidence not known
    hyperkalemia / Delayed / Incidence not known
    rhabdomyolysis / Delayed / Incidence not known
    hearing loss / Delayed / Incidence not known
    serotonin syndrome / Delayed / Incidence not known

    Moderate

    constipation / Delayed / 4.0-4.0
    withdrawal / Early / 0-1.0
    euphoria / Early / 0-1.0
    myoclonia / Delayed / 0-1.0
    memory impairment / Delayed / 0-1.0
    confusion / Early / 0-1.0
    dyspnea / Early / 0-1.0
    dysuria / Early / 1.0-1.0
    migraine / Early / 0-1.0
    erythema / Early / 1.0-1.0
    palpitations / Early / 0-1.0
    hypertension / Early / 0-1.0
    blurred vision / Early / 0-1.0
    peripheral edema / Delayed / 1.0-1.0
    elevated hepatic enzymes / Delayed / 1.0
    psychological dependence / Delayed / Incidence not known
    physiological dependence / Delayed / Incidence not known
    tolerance / Delayed / Incidence not known
    depression / Delayed / Incidence not known
    dysphoria / Early / Incidence not known
    hallucinations / Early / Incidence not known
    respiratory depression / Rapid / Incidence not known
    tachypnea / Early / Incidence not known
    hypoventilation / Rapid / Incidence not known
    encephalopathy / Delayed / Incidence not known
    hepatitis / Delayed / Incidence not known
    hypoprothrombinemia / Delayed / Incidence not known
    hyperbilirubinemia / Delayed / Incidence not known
    jaundice / Delayed / Incidence not known
    urinary retention / Early / Incidence not known
    neutropenia / Delayed / Incidence not known
    thrombocytopenia / Delayed / Incidence not known
    edema / Delayed / Incidence not known
    contact dermatitis / Delayed / Incidence not known
    chest pain (unspecified) / Early / Incidence not known
    orthostatic hypotension / Delayed / Incidence not known
    sinus tachycardia / Rapid / Incidence not known
    hypotension / Rapid / Incidence not known
    hyperemia / Delayed / Incidence not known
    dehydration / Delayed / Incidence not known
    hypoglycemia / Early / Incidence not known
    hyperglycemia / Delayed / Incidence not known
    metabolic acidosis / Delayed / Incidence not known
    infertility / Delayed / Incidence not known
    impotence (erectile dysfunction) / Delayed / Incidence not known
    adrenocortical insufficiency / Delayed / Incidence not known

    Mild

    nausea / Early / 4.1-31.0
    dizziness / Early / 13.0-13.0
    headache / Early / 10.0-10.0
    vomiting / Early / 4.8-9.0
    drowsiness / Early / 4.0-4.0
    rash (unspecified) / Early / 2.0-2.0
    paresthesias / Delayed / 0-1.0
    tremor / Early / 0-1.0
    anxiety / Delayed / 0-1.0
    hiccups / Early / 0-1.0
    throat irritation / Early / 0-1.0
    abdominal pain / Early / 0-1.0
    anorexia / Delayed / 0-1.0
    ecchymosis / Delayed / 0-1.0
    urticaria / Rapid / 0-1.0
    hyperhidrosis / Delayed / 0-1.0
    pruritus / Rapid / 1.0-1.0
    flushing / Rapid / 0-1.0
    chills / Rapid / 0-1.0
    malaise / Early / 0-1.0
    polydipsia / Early / 0-1.0
    asthenia / Delayed / 0-1.0
    arthralgia / Delayed / 0-1.0
    tinnitus / Delayed / 0-1.0
    insomnia / Early / 1.0
    cough / Delayed / 1.0
    xerostomia / Early / 1.0
    diarrhea / Early / 1.0
    dyspepsia / Early / 1.0
    fatigue / Early / 1.0
    agitation / Early / Incidence not known
    hypoesthesia / Delayed / Incidence not known
    lethargy / Early / Incidence not known
    flatulence / Early / Incidence not known
    dysgeusia / Early / Incidence not known
    purpura / Delayed / Incidence not known
    syncope / Early / Incidence not known
    miosis / Early / Incidence not known
    diaphoresis / Early / Incidence not known
    hypothermia / Delayed / Incidence not known
    myalgia / Early / Incidence not known
    amenorrhea / Delayed / Incidence not known
    gonadal suppression / Delayed / Incidence not known
    libido decrease / Delayed / Incidence not known

    DRUG INTERACTIONS

    Abacavir; Lamivudine, 3TC; Zidovudine, ZDV: (Minor) Both acetaminophen and zidovudine, ZDV undergo glucuronidation. Competition for the metabolic pathway is thought to have caused a case of acetaminophen-related hepatotoxicity. This interaction may be more clinically significant in patients with depleted glutathione stores, such as patients with acquired immunodeficiency syndrome, poor nutrition, or alcoholism.
    Acarbose: (Minor) It has been suggested by in vitro and in vivo animal studies that acarbose augments the activity of the hepatic isoenzyme CYP2E1, which is responsible for metabolism of acetaminophen to its toxic reactive metabolite. Patients should avoid the combination of acarbose with acetaminophen and ethanol until more is known about the potential for clinically significant interactions.
    Acetaminophen; Aspirin, ASA; Caffeine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Butalbital: (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    Acetaminophen; Butalbital; Caffeine: (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    Acetaminophen; Butalbital; Caffeine; Codeine: (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. (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    Acetaminophen; Caffeine; Dihydrocodeine: (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; Caffeine; Magnesium Salicylate; Phenyltoloxamine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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. (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. Although salicylates are rarely associated with nephrotoxicity, high-dose, chronic administration of salicylates combined other analgesics, including acetaminophen, significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Additive hepatic toxicity may occur, especially in combined overdose situations. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Acetaminophen; Caffeine; Phenyltoloxamine; Salicylamide: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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; Chlorpheniramine; Phenylephrine; Phenyltoloxamine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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; Codeine: (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; Dextromethorphan; Doxylamine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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; Diphenhydramine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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; 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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression.
    Acetaminophen; Pentazocine: (Major) Avoid the concomitant use of pentazocine and opiate agonists, such as oxycodone. Pentazocine is a mixed opiate agonist/antagonist that may block the effects of opiate agonists and reduce analgesic effects of oxycodone. 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.
    Acetaminophen; Propoxyphene: (Major) Propoxyphene is a weak mu-opiate receptor agonist. As other opiate agonists bind to mu-opiate receptors, concurrent use of an opiate agonist with propoxyphene is not desirable. Also, propoxyphene will only partially suppress the withdrawal syndrome in patients physically dependent on morphine or other narcotics. The choice of one mu-opiate receptor agonist needs to be made to avoid duplicate therapy and possible adverse effects. For example, concomitant use of propoxyphene with other CNS depressants (e.g., other opiate agonists) can potentiate the effects of respiratory depression and/or sedation. Propoxyphene in combination with other CNS depressants is a major cause of drug-related death. Fatalities within the first hour of overdosage are not uncommon. Extreme caution is needed during concomitant use of any CNS-depressant drug and propoxyphene. 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; Tramadol: (Major) Concomitant use of tramadol increases the seizure risk in patients taking opiate agonists. Also, tramadol can cause additive CNS depression and respiratory depression when used with opiate agonists; avoid concurrent use whenever possible. If used together, extreme caution is needed, and a reduced tramadol dose is recommended.
    Acrivastine; Pseudoephedrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    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.
    Alfentanil: (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.
    Aliskiren; Amlodipine; Hydrochlorothiazide, HCTZ: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Aliskiren; Hydrochlorothiazide, HCTZ: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Almotriptan: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as serotonin-receptor agonists. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    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.
    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 oxycodone is initiated in a patient taking a benzodiazepine, reduce dosages and titrate to clinical response. For acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours, and for other oxycodone products, use an initial dose of oxycodone at one-third to one-half the usual dosage. 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.
    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 will 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; Hydrochlorothiazide, HCTZ: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Amiodarone: (Major) Coadministration of amiodarone, an inhibitor of CYP3A4 and CYP2D6, and oxycodone, a substrate of CYP3A4 and CYP2D6, may increase oxycodone plasma concentrations and increase or prolong related toxicities including potentially fatal respiratory depression. If therapy with both agents is necessary, monitor patient for an extended period of time and adjust dosage as necessary; oxycodone dosage adjustments may be needed if the CYP3A4 inhibitor is discontinued. Concurrent administration of oxycodone and voriconazole, another CYP3A4 inhibitor, increased oxycodone AUC by 3.6-fold and the Cmax by 1.7-fold.
    Amitriptyline: (Moderate) Concomitant use of oxycodone and tricyclic antidepressants (TCAs) may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Orthostasis may occur in ambulatory patients. Constipation occurs with both oxycodone and TCA use. Prior to concurrent use of oxycodone in patients taking a TCA, 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 TCA is used concurrently with oxycodone, a reduced dosage of oxycodone is recommended; use an initial dose of oxycodone at one-third to one-half the usual dosage. Monitor for sedation and respiratory depression and for reduced GI motility. Caution should also be observed when administering TCAs with opiates having serotonergic properties such as oxycodone. Serotonin syndrome may rarely occur and is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma). If serotonin syndrome is suspected, both the TCA and concurrent serotonergic agents should be discontinued.
    Amitriptyline; 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 oxycodone is initiated in a patient taking a benzodiazepine, reduce dosages and titrate to clinical response. For acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours, and for other oxycodone products, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. 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. (Moderate) Concomitant use of oxycodone and tricyclic antidepressants (TCAs) may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Orthostasis may occur in ambulatory patients. Constipation occurs with both oxycodone and TCA use. Prior to concurrent use of oxycodone in patients taking a TCA, 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 TCA is used concurrently with oxycodone, a reduced dosage of oxycodone is recommended; use an initial dose of oxycodone at one-third to one-half the usual dosage. Monitor for sedation and respiratory depression and for reduced GI motility. Caution should also be observed when administering TCAs with opiates having serotonergic properties such as oxycodone. Serotonin syndrome may rarely occur and is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma). If serotonin syndrome is suspected, both the TCA and concurrent serotonergic agents should be discontinued.
    Amlodipine; Hydrochlorothiazide, HCTZ; Olmesartan: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Amlodipine; Hydrochlorothiazide, HCTZ; Valsartan: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Amobarbital: (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    Amoxapine: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as amoxapine, can lead to additive respiratory depression, hypotension, profound sedation, or coma. Prior to concurrent use of oxycodone in patients taking amoxapine, 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone at one-third to one-half the usual dosage in patients that are concurrently receiving another CNS depressant. Also, consider using a lower amoxapine dose. Monitor patients for sedation and respiratory depression.
    Amoxicillin; Clarithromycin; Lansoprazole: (Moderate) Coadministration of clarithromycin (a CYP3A4 inhibitor) and oxycodone (a CYP3A4 substrate) may result in increased oxycodone plasma concentrations and a higher risk for adverse or prolonged effects. If coadministration of these agents is necessary, patients should be monitored at frequent intervals and dosage adjustments made if warranted.
    Amoxicillin; Clarithromycin; Omeprazole: (Moderate) Coadministration of clarithromycin (a CYP3A4 inhibitor) and oxycodone (a CYP3A4 substrate) may result in increased oxycodone plasma concentrations and a higher risk for adverse or prolonged effects. If coadministration of these agents is necessary, patients should be monitored at frequent intervals and dosage adjustments made if warranted.
    Amyl Nitrite: (Moderate) Administration of nitrates such as amyl nitrite to patients receiving other hypotension-producing agents, such as opiate agonists, can cause additive hypotensive or orthostatic effects.
    Antacids: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
    Anticholinergics: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when oxycodone is used concomitantly with an anticholinergic drug. The concomitant use of oxycodone and anticholinergic drugs 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.
    Apomorphine: (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: (Major) Use caution if oxycodone and aprepitant, fosaprepitant are used concurrently and monitor for an increase in oxycodone-related adverse effects, including excess sedation, for several days after administration of a multi-day aprepitant regimen. Oxycodone is a CYP3A4 substrate. Aprepitant, when administered as a 3-day oral regimen (125 mg/80 mg/80 mg), is a moderate CYP3A4 inhibitor and inducer and may increase plasma concentrations of oxycodone. For example, a 5-day oral aprepitant regimen increased the AUC of another CYP3A4 substrate, midazolam (single dose), by 2.3-fold on day 1 and by 3.3-fold on day 5. After a 3-day oral aprepitant regimen, the AUC of midazolam (given on days 1, 4, 8, and 15) increased by 25% on day 4, and then decreased by 19% and 4% on days 8 and 15, respectively. As a single 125 mg or 40 mg oral dose, the inhibitory effect of aprepitant on CYP3A4 is weak, with the AUC of midazolam increased by 1.5-fold and 1.2-fold, respectively. After administration, fosaprepitant is rapidly converted to aprepitant and shares many of the same drug interactions. However, as a single 150 mg intravenous dose, fosaprepitant only weakly inhibits CYP3A4 for a duration of 2 days; there is no evidence of CYP3A4 induction. Fosaprepitant 150 mg IV as a single dose increased the AUC of midazolam (given on days 1 and 4) by approximately 1.8-fold on day 1; there was no effect on day 4. Less than a 2-fold increase in the midazolam AUC is not considered clinically important. (Minor) Use caution if acetaminophen and aprepitant are used concurrently and monitor for an increase in acetaminophen-related adverse effects for several days after administration of a multi-day aprepitant regimen. Acetaminophen is a minor (10 to 15%) substrate of CYP3A4. Aprepitant, when administered as a 3-day oral regimen (125 mg/80 mg/80 mg), is a moderate CYP3A4 inhibitor and inducer and may increase plasma concentrations of acetaminophen. For example, a 5-day oral aprepitant regimen increased the AUC of another CYP3A4 substrate, midazolam (single dose), by 2.3-fold on day 1 and by 3.3-fold on day 5. After a 3-day oral aprepitant regimen, the AUC of midazolam (given on days 1, 4, 8, and 15) increased by 25% on day 4, and then decreased by 19% and 4% on days 8 and 15, respectively. As a single 125 mg or 40 mg oral dose, the inhibitory effect of aprepitant on CYP3A4 is weak, with the AUC of midazolam increased by 1.5-fold and 1.2-fold, respectively. After administration, fosaprepitant is rapidly converted to aprepitant and shares many of the same drug interactions. However, as a single 150 mg intravenous dose, fosaprepitant only weakly inhibits CYP3A4 for a duration of 2 days; there is no evidence of CYP3A4 induction. Fosaprepitant 150 mg IV as a single dose increased the AUC of midazolam (given on days 1 and 4) by approximately 1.8-fold on day 1; there was no effect on day 4. Less than a 2-fold increase in the midazolam AUC is not considered clinically important.
    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 will 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.
    Asenapine: (Moderate) Drugs that can cause CNS depression, if used concomitantly with asenapine, may increase both the frequency and the intensity of adverse effects such as drowsiness, sedation, and dizziness. Caution should be used when asenapine is given in combination with other centrally-acting medications including opiate agonists.
    Aspirin, ASA: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Aspirin, ASA; Butalbital; Caffeine: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy. (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    Aspirin, ASA; Butalbital; Caffeine; Codeine: (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. (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy. (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    Aspirin, ASA; Caffeine; Dihydrocodeine: (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. (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Aspirin, ASA; Carisoprodol: (Major) Concomitant use of opiate agonists with skeletal muscle relaxants may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with skeletal muscle relaxants 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 oxycodone or oxycodone; naloxone is initiated in a patient taking a skeletal muscle relaxant, use an initial dose of oxycodone at one-third to one-half the usual dosage and titrate to clinical response; reduced initial doses of oxycodone; naltrexone, aspirin, ASA; oxycodone, and ibuprofen; oxycodone are also recommended. If a decision is made to start treatment with acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours. If a skeletal muscle relaxant is prescribed for a patient taking an opiate agonist, use a lower initial dose of the skeletal muscle relaxant and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Aspirin, ASA; Carisoprodol; Codeine: (Major) Concomitant use of opiate agonists with skeletal muscle relaxants may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with skeletal muscle relaxants 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 oxycodone or oxycodone; naloxone is initiated in a patient taking a skeletal muscle relaxant, use an initial dose of oxycodone at one-third to one-half the usual dosage and titrate to clinical response; reduced initial doses of oxycodone; naltrexone, aspirin, ASA; oxycodone, and ibuprofen; oxycodone are also recommended. If a decision is made to start treatment with acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours. If a skeletal muscle relaxant is prescribed for a patient taking an opiate agonist, use a lower initial dose of the skeletal muscle relaxant and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. (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. (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Aspirin, ASA; Dipyridamole: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Aspirin, ASA; Omeprazole: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Aspirin, ASA; Oxycodone: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Aspirin, ASA; Pravastatin: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. High-dose, chronic administration of the combined analgesics significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Atazanavir: (Major) Coadministration of atazanavir, a CYP3A4 inhibitor and substrate, and oxycodone, a CYP3A4 substrate, may increase oxycodone plasma concentrations and increase or prolong related toxicities including potentially fatal respiratory depression. If therapy with both agents is necessary, monitor patient for an extended period of time and adjust dosage as necessary; oxycodone dosage adjustments may be needed if the CYP3A4 inhibitor is discontinued. Concurrent administration of oxycodone and voriconazole, another CYP3A4 inhibitor, increased oxycodone AUC by 3.6-fold and the Cmax by 1.7-fold.
    Atazanavir; Cobicistat: (Major) Coadministration of atazanavir, a CYP3A4 inhibitor and substrate, and oxycodone, a CYP3A4 substrate, may increase oxycodone plasma concentrations and increase or prolong related toxicities including potentially fatal respiratory depression. If therapy with both agents is necessary, monitor patient for an extended period of time and adjust dosage as necessary; oxycodone dosage adjustments may be needed if the CYP3A4 inhibitor is discontinued. Concurrent administration of oxycodone and voriconazole, another CYP3A4 inhibitor, increased oxycodone AUC by 3.6-fold and the Cmax by 1.7-fold. (Moderate) The plasma concentrations of oxycodone may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as oversedation, respiratory depression, and hypotension, is recommended during coadministration. Cobicistat is a CYP3A4 and CYP2D6 inhibitor, while oxycodone is a CYP3A4 and CYP2D6 substrate.
    Atenolol; Chlorthalidone: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Atomoxetine: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as serotonin norepinephrine reuptake inhibitors (SNRIs). Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Atracurium: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as neuromuscular blockers, can potentiate the effects of alfentanil on respiration, alertness, and blood pressure. A dose reduction of one or both drugs may be warranted.
    Atropine; Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as methylene blue. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Atropine; Difenoxin: (Major) 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.
    Atropine; Diphenoxylate: (Major) 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.
    Atropine; Hyoscyamine; Phenobarbital; Scopolamine: (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    Azelastine: (Moderate) An enhanced CNS depressant effect may occur when azelastine is combined with other CNS depressants including opiate agonists. A dose reduction of one or both drugs may be warranted.
    Azelastine; Fluticasone: (Moderate) An enhanced CNS depressant effect may occur when azelastine is combined with other CNS depressants including opiate agonists. A dose reduction of one or both drugs may be warranted.
    Azilsartan; Chlorthalidone: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Baclofen: (Major) Concomitant use of opiate agonists with skeletal muscle relaxants may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with skeletal muscle relaxants 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 oxycodone or oxycodone; naloxone is initiated in a patient taking a skeletal muscle relaxant, use an initial dose of oxycodone at one-third to one-half the usual dosage and titrate to clinical response; reduced initial doses of oxycodone; naltrexone, aspirin, ASA; oxycodone, and ibuprofen; oxycodone are also recommended. If a decision is made to start treatment with acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours. If a skeletal muscle relaxant is prescribed for a patient taking an opiate agonist, use a lower initial dose of the skeletal muscle relaxant and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
    Barbiturates: (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    Basiliximab: (Major) Coadministration of basiliximab, an indirect down-regulator of CYP3A4, and oxycodone, a CYP3A4 substrate, may increase oxycodone plasma concentrations and increase or prolong related toxicities including potentially fatal respiratory depression. If therapy with both agents is necessary, monitor patient for an extended period of time and adjust dosage as necessary; oxycodone dosage adjustments may be needed if the CYP3A4 inhibitor is discontinued. Concurrent administration of oxycodone and voriconazole, another CYP3A4 inhibitor, increased oxycodone AUC by 3.6-fold and the Cmax by 1.7-fold.
    Belladonna Alkaloids; Ergotamine; Phenobarbital: (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    Belladonna; Opium: (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.
    Benazepril; Hydrochlorothiazide, HCTZ: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Bendroflumethiazide; Nadolol: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as methylene blue. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Benzonatate: (Moderate) Coadministration of oxycodone and benzonatate may result in additive CNS depression.
    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.
    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) Prolonged concurrent use of acetaminophen and salicylates is not recommended. Although salicylates are rarely associated with nephrotoxicity, high-dose, chronic administration of salicylates combined other analgesics, including acetaminophen, significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Additive hepatic toxicity may occur, especially in combined overdose situations. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    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) Prolonged concurrent use of acetaminophen and salicylates is not recommended. Although salicylates are rarely associated with nephrotoxicity, high-dose, chronic administration of salicylates combined other analgesics, including acetaminophen, significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Additive hepatic toxicity may occur, especially in combined overdose situations. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Bisoprolol; Hydrochlorothiazide, HCTZ: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Boceprevir: (Moderate) Close clinical monitoring is advised when administering acetaminophen with boceprevir due to an increased potential for acetaminophen-related adverse events. If acetaminophen dose adjustments are made, re-adjust the dose upon completion of boceprevir treatment. Although this interaction has not been studied, predictions about the interaction can be made based on the metabolic pathway of acetaminophen. Acetaminophen is partially metabolized by the hepatic isoenzyme CYP3A4; boceprevir inhibits this isoenzyme. Coadministration may result in elevated acetaminophen plasma concentrations. (Moderate) Close clinical monitoring is advised when administering oxycodone with boceprevir due to an increased potential for oxycodone-related adverse events. If oxycodone dose adjustments are made, re-adjust the dose upon completion of boceprevir treatment. Although this interaction has not been studied, predictions about the interaction can be made based on the metabolic pathway of oxycodone. Oxycodone is partially metabolized by the hepatic isoenzyme CYP3A4; boceprevir inhibits this isoenzyme. Coadministration may result in elevated oxycodone plasma concentrations.
    Brexpiprazole: (Moderate) Due to the CNS effects of brexpiprazole, caution is advisable when brexpiprazole is given in combination with other centrally-acting medications including opiate agonists.
    Brigatinib: (Moderate) Monitor for decreased efficacy of oxycodone, including signs and symptoms of opioid withdrawal in patients who are physically dependent on oxycodone, if coadministration with brigatinib is necessary. Oxycodone is a CYP3A substrate and brigatinib induces CYP3A in vitro; plasma concentrations of oxycodone may decrease.
    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.
    Brompheniramine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Brompheniramine; Carbetapentane; Phenylephrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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. (Moderate) Drowsiness has been reported during administration of carbetapentane. An enhanced CNS depressant effect may occur when carbetapentane is combined with other CNS depressants including morphine.
    Brompheniramine; Dextromethorphan; Guaifenesin: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Brompheniramine; 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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression. (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Brompheniramine; 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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression. (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Brompheniramine; Pseudoephedrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    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 will 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 will 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 will 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) Buprenorphine is a mixed opiate agonist/antagonist with strong affinity for the mu-receptor that may partially block the effects of full mu-receptor opiate agonists and reduce analgesic effects. In some cases of acute pain, trauma, or during surgical management, opiate-dependent patients receiving buprenorphine maintenance therapy may require concurrent treatment with opiate agonists, such as oxycodone. In these cases, health care professionals must exercise caution in opiate agonist dose selection, as higher doses of an opiate agonist may be required to compete with buprenorphine at the mu-receptor. Management strategies may include adding a short-acting opiate agonist to achieve analgesia in the presence of buprenorphine, discontinuation of buprenorphine and use of an opiate agonist to avoid withdrawal and achieve analgesia, or conversion of buprenorphine to methadone while using additional opiate agonists if needed. Closely monitor patients for CNS or respiratory depression. When buprenorphine is used for analgesia, avoid co-use with opiate agonists. Buprenorphine may cause withdrawal symptoms in patients receiving chronic opiate agonists as well as possibly potentiate 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.
    Buprenorphine; Naloxone: (Major) Buprenorphine is a mixed opiate agonist/antagonist with strong affinity for the mu-receptor that may partially block the effects of full mu-receptor opiate agonists and reduce analgesic effects. In some cases of acute pain, trauma, or during surgical management, opiate-dependent patients receiving buprenorphine maintenance therapy may require concurrent treatment with opiate agonists, such as oxycodone. In these cases, health care professionals must exercise caution in opiate agonist dose selection, as higher doses of an opiate agonist may be required to compete with buprenorphine at the mu-receptor. Management strategies may include adding a short-acting opiate agonist to achieve analgesia in the presence of buprenorphine, discontinuation of buprenorphine and use of an opiate agonist to avoid withdrawal and achieve analgesia, or conversion of buprenorphine to methadone while using additional opiate agonists if needed. Closely monitor patients for CNS or respiratory depression. When buprenorphine is used for analgesia, avoid co-use with opiate agonists. Buprenorphine may cause withdrawal symptoms in patients receiving chronic opiate agonists as well as possibly potentiate 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) Naloxone can antagonize the therapeutic efficacy of oxycodone in addition to precipitating withdrawal symptoms in patients who are physically dependent on opiate drugs including oxycodone.
    Bupropion: (Moderate) Bupropion is an inhibitor of the CYP2D6 isoenzyme. Plasma concentrations of opiate agents metabolized by CYP2D6 such as oxycodone may be increased if bupropion is added. Dosage reductions in these agents may be needed. Conversely, if bupropion therapy is discontinued, dosages of these agents may need to be adjusted upward in some patients. Excessive use of opioid agonists (e.g., opiate addiction) is associated with an increased seizure risk; seizures may be more likely to occur during concurrent use of bupropion in these patients since bupropion is associated with a dose-related risk of seizures.
    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. 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) Bupropion is an inhibitor of the CYP2D6 isoenzyme. Plasma concentrations of opiate agents metabolized by CYP2D6 such as oxycodone may be increased if bupropion is added. Dosage reductions in these agents may be needed. Conversely, if bupropion therapy is discontinued, dosages of these agents may need to be adjusted upward in some patients. Excessive use of opioid agonists (e.g., opiate addiction) is associated with an increased seizure risk; seizures may be more likely to occur during concurrent use of bupropion in these patients since bupropion is associated with a dose-related risk of seizures.
    Buspirone: (Moderate) Concomitant use of CNS depressants, such as buspirone, can potentiate the effects of oxycodone, 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.
    Busulfan: (Moderate) Use busulfan and acetaminophen together with caution; concomitant use may result in increased busulfan levels and increased busulfan toxicity. Separating the administration of these drugs may mitigate this interaction; avoid giving acetaminophen within 72 hours prior to or concurrently with busulfan. Busulfan is metabolized in the liver through conjugation with glutathione; acetaminophen decreases glutathione levels in the blood and tissues and may reduce the clearance of busulfan.
    Butabarbital: (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    Butorphanol: (Major) Avoid the concomitant use of butorphanol and opiate agonists, such as oxycodone. Butorphanol is a mixed opiate agonist/antagonist that may block the effects of opiate agonists and reduce analgesic effects. 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.
    Candesartan; Hydrochlorothiazide, HCTZ: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Capsaicin; Metaxalone: (Major) Concomitant use of opiate agonists with skeletal muscle relaxants may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with skeletal muscle relaxants 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 oxycodone or oxycodone; naloxone is initiated in a patient taking a skeletal muscle relaxant, use an initial dose of oxycodone at one-third to one-half the usual dosage and titrate to clinical response; reduced initial doses of oxycodone; naltrexone, aspirin, ASA; oxycodone, and ibuprofen; oxycodone are also recommended. If a decision is made to start treatment with acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours. If a skeletal muscle relaxant is prescribed for a patient taking an opiate agonist, use a lower initial dose of the skeletal muscle relaxant and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
    Captopril; Hydrochlorothiazide, HCTZ: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Carbamazepine: (Moderate) Inducers of CYP3A4 such as carbamazepine may induce the hepatic metabolism of opiate agonists, which may lead to opiate withdrawal or inadequate pain control. This interaction is most significant if the enzyme-inducing agent is added after opiate therapy has begun in patients who are opiate tolerant. Clinicians should be alert to changes in the effect of the opioid agonist. Opiate doses may need to be increased if carbamazepine is added. Conversely, doses may need to be decreased if carbamazepine is discontinued. (Minor) Carbamazepine may potentially accelerate the hepatic metabolism of acetaminophen. In addition, due to enzyme induction, carbamazepine may increase the risk for acetaminophen-induced hepatotoxicity via generation of a greater percentage of acetaminophen's hepatotoxic metabolite, NAPQI. Clinicians should be alert to decreased effect of acetaminophen. Dosage adjustments may be necessary, and closer monitoring of clinical and/or adverse effects is warranted.
    Carbetapentane; Chlorpheniramine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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. (Moderate) Drowsiness has been reported during administration of carbetapentane. An enhanced CNS depressant effect may occur when carbetapentane is combined with other CNS depressants including morphine.
    Carbetapentane; Chlorpheniramine; Phenylephrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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. (Moderate) Drowsiness has been reported during administration of carbetapentane. An enhanced CNS depressant effect may occur when carbetapentane is combined with other CNS depressants including morphine.
    Carbetapentane; Diphenhydramine; Phenylephrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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. (Moderate) Drowsiness has been reported during administration of carbetapentane. An enhanced CNS depressant effect may occur when carbetapentane is combined with other CNS depressants including morphine.
    Carbetapentane; Guaifenesin: (Moderate) Drowsiness has been reported during administration of carbetapentane. An enhanced CNS depressant effect may occur when carbetapentane is combined with other CNS depressants including morphine.
    Carbetapentane; Guaifenesin; Phenylephrine: (Moderate) Drowsiness has been reported during administration of carbetapentane. An enhanced CNS depressant effect may occur when carbetapentane is combined with other CNS depressants including morphine.
    Carbetapentane; Phenylephrine: (Moderate) Drowsiness has been reported during administration of carbetapentane. An enhanced CNS depressant effect may occur when carbetapentane is combined with other CNS depressants including morphine.
    Carbetapentane; Phenylephrine; Pyrilamine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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. (Moderate) Drowsiness has been reported during administration of carbetapentane. An enhanced CNS depressant effect may occur when carbetapentane is combined with other CNS depressants including morphine.
    Carbetapentane; Pseudoephedrine: (Moderate) Drowsiness has been reported during administration of carbetapentane. An enhanced CNS depressant effect may occur when carbetapentane is combined with other CNS depressants including morphine.
    Carbetapentane; Pyrilamine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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. (Moderate) Drowsiness has been reported during administration of carbetapentane. An enhanced CNS depressant effect may occur when carbetapentane is combined with other CNS depressants including morphine.
    Carbidopa; Levodopa; Entacapone: (Moderate) Concomitant use of opiate agonists with other central nervous system (CNS) depressants such as COMT inhibitors can potentiate the effects of the opiate and may lead to additive CNS or respiratory depression, profound sedation, or coma. Prior to concurrent use of an opiate 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 the opiate 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.
    Carbinoxamine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Carbinoxamine; Dextromethorphan; Pseudoephedrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Carbinoxamine; Hydrocodone; Phenylephrine: (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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression. (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Carbinoxamine; 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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression. (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Carbinoxamine; Phenylephrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Carbinoxamine; Pseudoephedrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Cariprazine: (Moderate) Due to the CNS effects of cariprazine, caution is advisable when cariprazine is given in combination with other centrally-acting medications including opiate agonists.
    Carisoprodol: (Major) Concomitant use of opiate agonists with skeletal muscle relaxants may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with skeletal muscle relaxants 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 oxycodone or oxycodone; naloxone is initiated in a patient taking a skeletal muscle relaxant, use an initial dose of oxycodone at one-third to one-half the usual dosage and titrate to clinical response; reduced initial doses of oxycodone; naltrexone, aspirin, ASA; oxycodone, and ibuprofen; oxycodone are also recommended. If a decision is made to start treatment with acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours. If a skeletal muscle relaxant is prescribed for a patient taking an opiate agonist, use a lower initial dose of the skeletal muscle relaxant and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
    Ceritinib: (Moderate) Monitor frequently for an increase in oxycodone-related adverse reactions (e.g., sedation, respiratory depression) if coadministered with ceritinib. Consider dosage reduction of oxycodone until stable drug effects are achieved if concurrent use is necessary. If ceritinib is discontinued, consider an increased dose of oxycodone and monitor for signs of opioid withdrawal. Ceritinib is an inhibitor of CYP3A and oxycodone is a CYP3A4 substrate.
    Cetirizine: (Moderate) Additive drowsiness may occur if cetirizine or levocetirizine is administered with other drugs that depress the CNS, including opiate agonists.
    Cetirizine; Pseudoephedrine: (Moderate) Additive drowsiness may occur if cetirizine or levocetirizine is administered with other drugs that depress the CNS, including opiate agonists.
    Charcoal: (Minor) Activated charcoal binds many drugs within the gut. Administering charcoal dietary supplements at the same time as a routine acetaminophen dosage would be expected to interfere with the analgesic and antipyretic efficacy of acetaminophen. Charcoal is mostly used in the setting of acetaminophen overdose; however, patients should never try to treat an acetaminophen overdose with charcoal dietary supplements. Advise patients to get immediate medical attention for an acetaminophen overdose.
    Chlophedianol; Dexchlorpheniramine; Pseudoephedrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Chloramphenicol: (Moderate) Concomitant use of oxycodone with chloramphenicol may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of chloramphenicol could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If chloramphenicol is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and chloramphenicol is a CYP3A4 inhibitor.
    Chlorcyclizine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    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 oxycodone is initiated in a patient taking a benzodiazepine, reduce dosages and titrate to clinical response. For acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours, and for other oxycodone products, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. 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.
    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 oxycodone is initiated in a patient taking a benzodiazepine, reduce dosages and titrate to clinical response. For acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours, and for other oxycodone products, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. 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.
    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) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Chlorpheniramine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Chlorpheniramine; Codeine: (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. (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Chlorpheniramine; Dextromethorphan: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Chlorpheniramine; Dextromethorphan; Phenylephrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Chlorpheniramine; Dihydrocodeine; Phenylephrine: (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. (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Chlorpheniramine; Dihydrocodeine; Pseudoephedrine: (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. (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Chlorpheniramine; Guaifenesin; 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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression. (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression. (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Chlorpheniramine; Hydrocodone; Phenylephrine: (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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression. (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Chlorpheniramine; 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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression. (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Chlorpheniramine; Phenylephrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Chlorpheniramine; Pseudoephedrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Chlorpromazine: (Moderate) Concomitant use of oxycodone with phenothiazines may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Prior to 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. Furthermore, oxycodone is metabolized in part by 2D6 to oxymorphone, which represents < 15% of the total administered dose. Concurrent use of some agents that inhibit CYP2D6 (e.g., quinidine) has not been shown to result in clinically significant interactions. However, many phenothiazines are inhibitors of CYP2D6 (e.g., chlorpromazine, perphenazine, thioridazine) and may potentially increase the effects of oxycodone. Also, severe hypotension may be potentiated with concurrent phenothiazine usage or other drug that compromises vasomotor tone.
    Chlorthalidone: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Chlorthalidone; Clonidine: (Moderate) Clonidine has CNS depressive effects and can potentiate the actions of other CNS depressants including opiate agonists. (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Chlorzoxazone: (Major) Concomitant use of opiate agonists with skeletal muscle relaxants may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with skeletal muscle relaxants 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 oxycodone or oxycodone; naloxone is initiated in a patient taking a skeletal muscle relaxant, use an initial dose of oxycodone at one-third to one-half the usual dosage and titrate to clinical response; reduced initial doses of oxycodone; naltrexone, aspirin, ASA; oxycodone, and ibuprofen; oxycodone are also recommended. If a decision is made to start treatment with acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours. If a skeletal muscle relaxant is prescribed for a patient taking an opiate agonist, use a lower initial dose of the skeletal muscle relaxant and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
    Cholestyramine: (Moderate) Cholestyramine has been shown to decrease the absorption of acetaminophen by roughly 60%. Experts have recommended that cholestyramine not be given within 1 hour of acetaminophen if analgesic or antipyretic effect is to be achieved.
    Choline Salicylate; Magnesium Salicylate: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. Although salicylates are rarely associated with nephrotoxicity, high-dose, chronic administration of salicylates combined other analgesics, including acetaminophen, significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Additive hepatic toxicity may occur, especially in combined overdose situations. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Cimetidine: (Moderate) Concomitant use of oxycodone with cimetidine may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of cimetidine could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If cimetidine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and cimetidine is a CYP3A4 inhibitor.
    Cisatracurium: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as neuromuscular blockers, can potentiate the effects of alfentanil on respiration, alertness, and blood pressure. A dose reduction of one or both drugs may be warranted.
    Citalopram: (Moderate) The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment. Discontinue the suspected drugs if serotonin syndrome is suspected and manage cliinically. There has been a case report of possible serotonin syndrome caused by the combination of oxycodone and selective serotonin reuptake inhbitors (SSRIs).
    Clarithromycin: (Moderate) Coadministration of clarithromycin (a CYP3A4 inhibitor) and oxycodone (a CYP3A4 substrate) may result in increased oxycodone plasma concentrations and a higher risk for adverse or prolonged effects. If coadministration of these agents is necessary, patients should be monitored at frequent intervals and dosage adjustments made if warranted.
    Clemastine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    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 oxycodone is initiated in a patient taking a benzodiazepine, reduce dosages and titrate to clinical response. For acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours, and for other oxycodone products, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. 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.
    Clomipramine: (Moderate) Concomitant use of oxycodone and tricyclic antidepressants (TCAs) may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Orthostasis may occur in ambulatory patients. Constipation occurs with both oxycodone and TCA use. Prior to concurrent use of oxycodone in patients taking a TCA, 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 TCA is used concurrently with oxycodone, a reduced dosage of oxycodone is recommended; use an initial dose of oxycodone at one-third to one-half the usual dosage. Monitor for sedation and respiratory depression and for reduced GI motility. Caution should also be observed when administering TCAs with opiates having serotonergic properties such as oxycodone. Serotonin syndrome may rarely occur and is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma). If serotonin syndrome is suspected, both the TCA and concurrent serotonergic agents should be discontinued.
    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 oxycodone is initiated in a patient taking a benzodiazepine, reduce dosages and titrate to clinical response. For acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours, and for other oxycodone products, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. 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.
    Clonidine: (Moderate) Clonidine has CNS depressive effects and can potentiate the actions of other CNS depressants including opiate agonists.
    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 oxycodone is initiated in a patient taking a benzodiazepine, reduce dosages and titrate to clinical response. For acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours, and for other oxycodone products, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. 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.
    Clozapine: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as clozapine, can lead to additive respiratory depression, hypotension, profound sedation, or coma. In addition, this drug combination may result in additive effects on intestinal motility or bladder function. Prior to concurrent use of oxycodone in patients taking clozapine, 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone at one-third to one-half the usual dosage in patients that are concurrently receiving another CNS depressant. Also consider using a lower clozapine dose. Monitor patients for sedation and respiratory depression.
    Cobicistat: (Moderate) The plasma concentrations of oxycodone may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as oversedation, respiratory depression, and hypotension, is recommended during coadministration. Cobicistat is a CYP3A4 and CYP2D6 inhibitor, while oxycodone is a CYP3A4 and CYP2D6 substrate.
    Cobicistat; Elvitegravir; Emtricitabine; Tenofovir Alafenamide: (Moderate) The plasma concentrations of oxycodone may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as oversedation, respiratory depression, and hypotension, is recommended during coadministration. Cobicistat is a CYP3A4 and CYP2D6 inhibitor, while oxycodone is a CYP3A4 and CYP2D6 substrate.
    Cobicistat; Elvitegravir; Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) The plasma concentrations of oxycodone may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as oversedation, respiratory depression, and hypotension, is recommended during coadministration. Cobicistat is a CYP3A4 and CYP2D6 inhibitor, while oxycodone is a CYP3A4 and CYP2D6 substrate.
    Codeine: (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.
    Codeine; Guaifenesin: (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.
    Codeine; Phenylephrine; Promethazine: (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.
    Codeine; Promethazine: (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.
    COMT inhibitors: (Moderate) Concomitant use of opiate agonists with other central nervous system (CNS) depressants such as COMT inhibitors can potentiate the effects of the opiate and may lead to additive CNS or respiratory depression, profound sedation, or coma. Prior to concurrent use of an opiate 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 the opiate 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.
    Conivaptan: (Moderate) Concomitant use of oxycodone with conivaptan may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of conivaptan could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If conivaptan is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and conivaptan is a CYP3A4 inhibitor.
    Crizotinib: (Moderate) Concomitant use of oxycodone with crizotinib may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of crizotinib could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If crizotinib is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4. Crizotinib is a moderate inhibitor of CYP3A4.
    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) Concomitant use of oxycodone with sedating H1-blockers 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.
    Cyclobenzaprine: (Major) Concomitant use of opiate agonists with skeletal muscle relaxants may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with skeletal muscle relaxants 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 oxycodone or oxycodone; naloxone is initiated in a patient taking a skeletal muscle relaxant, use an initial dose of oxycodone at one-third to one-half the usual dosage and titrate to clinical response; reduced initial doses of oxycodone; naltrexone, aspirin, ASA; oxycodone, and ibuprofen; oxycodone are also recommended. If a decision is made to start treatment with acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours. If a skeletal muscle relaxant is prescribed for a patient taking an opiate agonist, use a lower initial dose of the skeletal muscle relaxant and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
    Cyproheptadine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Dalfopristin; Quinupristin: (Moderate) Concomitant use of oxycodone with dalfopristin; quinupristin may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of dalfopristin; quinupristin could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If dalfopristin; quinupristin is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and dalfopristin; quinupristin is a strong CYP3A4 inhibitor.
    Danazol: (Moderate) Concomitant use of oxycodone with danazol may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of danazol could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If danazol is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and danazol is a CYP3A4 inhibitor.
    Dantrolene: (Major) Concomitant use of opiate agonists with skeletal muscle relaxants may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with skeletal muscle relaxants 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 oxycodone or oxycodone; naloxone is initiated in a patient taking a skeletal muscle relaxant, use an initial dose of oxycodone at one-third to one-half the usual dosage and titrate to clinical response; reduced initial doses of oxycodone; naltrexone, aspirin, ASA; oxycodone, and ibuprofen; oxycodone are also recommended. If a decision is made to start treatment with acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours. If a skeletal muscle relaxant is prescribed for a patient taking an opiate agonist, use a lower initial dose of the skeletal muscle relaxant and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
    Darunavir: (Major) Coadministration of darunavir, a CYP3A4 inhibitor and substrate, and oxycodone, a CYP3A4 substrate, may increase oxycodone plasma concentrations and increase or prolong related toxicities including potentially fatal respiratory depression. If therapy with both agents is necessary, monitor patient for an extended period of time and adjust dosage as necessary; oxycodone dosage adjustments may be needed if the CYP3A4 inhibitor is discontinued. Concurrent administration of oxycodone and voriconazole, another CYP3A4 inhibitor, increased oxycodone AUC by 3.6-fold and the Cmax by 1.7-fold.
    Darunavir; Cobicistat: (Major) Coadministration of darunavir, a CYP3A4 inhibitor and substrate, and oxycodone, a CYP3A4 substrate, may increase oxycodone plasma concentrations and increase or prolong related toxicities including potentially fatal respiratory depression. If therapy with both agents is necessary, monitor patient for an extended period of time and adjust dosage as necessary; oxycodone dosage adjustments may be needed if the CYP3A4 inhibitor is discontinued. Concurrent administration of oxycodone and voriconazole, another CYP3A4 inhibitor, increased oxycodone AUC by 3.6-fold and the Cmax by 1.7-fold. (Moderate) The plasma concentrations of oxycodone may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects, such as oversedation, respiratory depression, and hypotension, is recommended during coadministration. Cobicistat is a CYP3A4 and CYP2D6 inhibitor, while oxycodone is a CYP3A4 and CYP2D6 substrate.
    Dasabuvir; Ombitasvir; Paritaprevir; Ritonavir: (Major) Oxycodone is metabolized by CYP3A4. Concomitant administration of ritonavir, a CYP3A4 inhibitor, may cause an increase in oxycodone plasma concentrations, which could increase or prolong adverse effects and may cause potentially fatal respiratory depression. If coadministration of these agents is necessary, patients should be monitored for an extended period and dosage adjustments made if warranted. In addition, oxycodone is metabolized in part by CYP2D6 to oxymorphone, which represents less than 15% of the total administered dose. Concurrent use of some agents that inhibit CYP2D6 has not been shown to result in clinically significant interactions. However, potent inhibitors of CYP2D6, such as ritonavir, may potentially increase the effects of oxycodone. Caution and close monitoring are advised if these drugs are administered together. Initiate oxycodone at low dosages and titrate carefully. (Moderate) Concurrent administration of acetaminophen with ritonavir may result in elevated acetaminophen plasma concentrations and subsequent adverse events. Acetaminophen is metabolized by the hepatic isoenzyme CYP3A4; ritonavir is an inhibitor of this enzyme. Caution and close monitoring are advised if these drugs are administered together.
    Dasatinib: (Moderate) Concomitant use of oxycodone with dasatinib may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of dasatinib could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If dasatinib is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and dasatinib is a CYP3A4 inhibitor.
    Delavirdine: (Major) Delavirdine, a potent CYP3A4 inhibitor, CYP3A4 substrate, and CYP2D6 inhibitor, may increase plasma concentrations of oxycodone, a substrate of CYP3A4 and CYP2D6. This may increase or prolong oxycodone-related toxicities including potentially fatal respiratory depression. If therapy with both agents is necessary, monitor patient for an extended period of time and adjust dosage as necessary; oxycodone dosage adjustments may be needed if the CYP inhibitor is discontinued. Concurrent administration of oxycodone and voriconazole, another CYP3A4 inhibitor, increased oxycodone AUC by 3.6-fold and the Cmax by 1.7-fold.
    Desflurane: (Moderate) Concurrent use with opiate agonists can decrease the minimum alveolar concentration (MAC) of desflurane needed to produce anesthesia.
    Desipramine: (Moderate) Concomitant use of oxycodone and tricyclic antidepressants (TCAs) may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Orthostasis may occur in ambulatory patients. Constipation occurs with both oxycodone and TCA use. Prior to concurrent use of oxycodone in patients taking a TCA, 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 TCA is used concurrently with oxycodone, a reduced dosage of oxycodone is recommended; use an initial dose of oxycodone at one-third to one-half the usual dosage. Monitor for sedation and respiratory depression and for reduced GI motility. Caution should also be observed when administering TCAs with opiates having serotonergic properties such as oxycodone. Serotonin syndrome may rarely occur and is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma). If serotonin syndrome is suspected, both the TCA and concurrent serotonergic agents should be discontinued.
    Desloratadine: (Minor) Although desloratadine is considered a 'non-sedating' antihistamine, rare CNS effects such as dizziness and sedation have been reported. For this reason, it would be prudent to monitor for drowsiness or dizziness when used concurrently with other CNS depressants such as opiate agonists.
    Desloratadine; Pseudoephedrine: (Minor) Although desloratadine is considered a 'non-sedating' antihistamine, rare CNS effects such as dizziness and sedation have been reported. For this reason, it would be prudent to monitor for drowsiness or dizziness when used concurrently with other CNS depressants such as opiate agonists.
    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.
    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 oxycodone or oxycodone; naloxone is initiated in a patient taking deutetrabenazine, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage and titrate to clinical response; reduced initial doses of oxycodone; naltrexone, aspirin, ASA; oxycodone, and ibuprofen; oxycodone are also recommended. If a decision is made to start treatment with acetaminophen; oxycodone extended-release tabIets, start with 1 tablet every 12 hours. 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.
    Dexchlorpheniramine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Dexchlorpheniramine; Dextromethorphan; Pseudoephedrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Dexmedetomidine: (Moderate) Co-administration of dexmedetomidine with opiate agonists likely to lead to an enhancement of CNS depression.
    Dexpanthenol: (Moderate) Use caution when using dexpanthenol with drugs that decrease gastrointestinal motility, such as opiate agonists, as it may decrease the effectiveness of dexpanthenol.
    Dextromethorphan; Diphenhydramine; Phenylephrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Dextromethorphan; Quinidine: (Moderate) Oxycodone is metabolized in part by cytochrome P450 2D6 to oxymorphone, which represents < 15% of the total administered dose. Potent inhibitors of CYP2D6, such as quinidine, may potentially increase the effects of oxycodone; however, such blockade has not been shown to be of clinical significance during oxycodone treatment. Clinicians should be aware of this possible interaction.
    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 oxycodone is initiated in a patient taking a benzodiazepine, reduce dosages and titrate to clinical response. For acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours, and for other oxycodone products, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. 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. If parental diazepam is used with an opiate agonist, reduce the opiate agonist dosage by at least 1/3. Educate patients about the risks and symptoms of respiratory depression and sedation.
    Diflunisal: (Moderate) Acetaminophen plasma concentrations can increase by approximately 50% following administration of diflunisal. Acetaminophen has no effect on diflunisal concentrations. Acetaminophen in high doses has been associated with severe hepatotoxic reactions; therefore, caution should be exercised when using these agents concomitantly.
    Dihydrocodeine; Guaifenesin; Pseudoephedrine: (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.
    Diltiazem: (Moderate) Concomitant use of oxycodone with diltiazem may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of diltiazem could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If diltiazem is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and diltiazem is a CYP3A4 inhibitor.
    Dimenhydrinate: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Diphenhydramine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Diphenhydramine; Hydrocodone; Phenylephrine: (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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression. (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Diphenhydramine; Ibuprofen: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Diphenhydramine; Naproxen: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Diphenhydramine; Phenylephrine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Dolasetron: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as serotonin-receptor antagonists. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Doxacurium: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as neuromuscular blockers, can potentiate the effects of alfentanil on respiration, alertness, and blood pressure. A dose reduction of one or both drugs may be warranted.
    Doxepin: (Moderate) Concomitant use of oxycodone and tricyclic antidepressants (TCAs) may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Orthostasis may occur in ambulatory patients. Constipation occurs with both oxycodone and TCA use. Prior to concurrent use of oxycodone in patients taking a TCA, 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 TCA is used concurrently with oxycodone, a reduced dosage of oxycodone is recommended; use an initial dose of oxycodone at one-third to one-half the usual dosage. Monitor for sedation and respiratory depression and for reduced GI motility. Caution should also be observed when administering TCAs with opiates having serotonergic properties such as oxycodone. Serotonin syndrome may rarely occur and is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma). If serotonin syndrome is suspected, both the TCA and concurrent serotonergic agents should be discontinued.
    Doxylamine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Doxylamine; Pyridoxine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Dronabinol, THC: (Moderate) Concomitant use of opiate agonists and other CNS depressants such as dronabinol, THC may result in respiratory depression, CNS depression, and/or hypotension. Prior to concurrent use of opiate agonists 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. When concomitant treatment is necessary, reduce the dose of 1 or both drugs. When levorphanol is used with dronabinol, reduce the initial levorphanol dose by approximately 50% or more.
    Dronedarone: (Moderate) Dronedarone is metabolized by CYP3A and is an inhibitor of CYP2D6 and CYP3A4. Oxycodone is a substrate for CYP2D6 and CYP3A4. The concomitant administration of dronedarone and CYP2D6 and CYP3A4 substrates may result in increased exposure of the substrate and should, therefore, be undertaken with caution.
    Droperidol: (Major) Concomitant use of oxycodone with other CNS depressants can lead to additive respiratory depression, hypotension, profound sedation, or coma. Drugs that may cause additive CNS effects include droperidol. 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. Ethanol abuse and the use of benzodiazepines and intravenous opiates are risk factors for the development of prolonged QT syndrome in patients receiving droperidol. Oxycodone should be used in reduced dosages if used concurrently with droperidol; initiate oxycodone at one-third to one-half the usual dosage in patients that are concurrently receiving droperidol. Monitor patients for sedation and respiratory depression.
    Drospirenone; Ethinyl Estradiol: (Moderate) Acetaminophen may increase plasma ethinyl estradiol levels, possibly by inhibition of conjugation. Patients taking acetaminophen concomitantly may experience an increase in estrogen related side effects.
    Drospirenone; Ethinyl Estradiol; Levomefolate: (Moderate) Acetaminophen may increase plasma ethinyl estradiol levels, possibly by inhibition of conjugation. Patients taking acetaminophen concomitantly may experience an increase in estrogen related side effects.
    Efavirenz: (Moderate) Concurrent use of oxycodone with efavirenz may decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If concomitant use is necessary, consider increasing the oxycodone dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal. Discontinuation of efavirenz may increase the risk of increased oxycodone-related adverse reactions, such as fatal respiratory depression. If efavirenz is discontinued, consider an oxycodone dosage reduction and monitor patients for respiratory depression and sedation at frequent intervals. Efavirenz is an inducer of CYP3A4 and oxycodone is a CYP3A4 substrate. (Minor) Drugs that induce the hepatic isoenzymes CYP2E1 and CYP1A2, such as efavirenz, may potentially increase the risk for acetaminophen-induced hepatotoxicity via generation of a greater percentage of acetaminophen's hepatotoxic metabolite, NAPQI. Also, the analgesic activity of acetaminophen may be reduced.
    Efavirenz; Emtricitabine; Tenofovir: (Moderate) Concurrent use of oxycodone with efavirenz may decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If concomitant use is necessary, consider increasing the oxycodone dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal. Discontinuation of efavirenz may increase the risk of increased oxycodone-related adverse reactions, such as fatal respiratory depression. If efavirenz is discontinued, consider an oxycodone dosage reduction and monitor patients for respiratory depression and sedation at frequent intervals. Efavirenz is an inducer of CYP3A4 and oxycodone is a CYP3A4 substrate. (Minor) Drugs that induce the hepatic isoenzymes CYP2E1 and CYP1A2, such as efavirenz, may potentially increase the risk for acetaminophen-induced hepatotoxicity via generation of a greater percentage of acetaminophen's hepatotoxic metabolite, NAPQI. Also, the analgesic activity of acetaminophen may be reduced.
    Elbasvir; Grazoprevir: (Moderate) Administering oxycodone with elbasvir; grazoprevir may result in elevated oxycodone plasma concentrations. Oxycodone 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: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as serotonin-receptor agonists. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Eliglustat: (Minor) Coadministration of oxycodone and eliglustat may result in increased concentrations of oxycodone, although the interaction does not appear to be clinically significant unless a 3A4 inhibitor is used concomitantly. Eliglustat is a CYP2D6 inhibitor. Although primarily metabolized by CYP3A, CYP2D6 also contributes to conversion of oxycodone to oxymorphone. If coadministration is necessary, use caution and monitor patients closely for opioid-related adverse effects such as respiratory depression and sedation at frequent intervals. Consider reducing the dosage of oxycodone until stable drug effects are achieved, and titrating to clinical effect.
    Eltrombopag: (Moderate) Eltrombopag is a UDP-glucuronyltransferase inhibitor. Acetaminophen is a substrate of UDP-glucuronyltransferases. The significance or effect of this interaction is not known; however, elevated concentrations of acetaminophen are possible. Monitor patients for adverse reactions if these drugs are coadministered. (Moderate) Eltrombopag is a UDP-glucuronyltransferase inhibitor. Opiate agonists are a substrate of UDP-glucuronyltransferases. The significance or effect of this interaction is not known; however, elevated concentrations of the opiate agonist is possible. Monitor patients for adverse reactions if eltrombopage is administered with an opiate agonist.
    Eluxadoline: (Major) Avoid use of eluxadoline with medications that may cause constipation, such as opiate agonists. 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. In addition, the CYP3A4 metabolism of some opiate agonists may be inhibited by eluxadoline. Although the CYP3A4 inhibitory effects of eluxadoline have not been definitively established, the manufacturer recommends caution when administering eluxadoline concurrently with CYP3A4 substrates that have a narrow therapeutic index, such as fentanyl and alfentanil. Closely monitor for increased side effects if these drugs are administered together. Discontinue use of eluxadoline in patients who develop severe constipation lasting more than 4 days.
    Enalapril; Hydrochlorothiazide, HCTZ: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Enflurane: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as general anesthetics, can lead to additive respiratory depression, hypotension, profound sedation, or coma. 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone 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. Monitor patients for sedation and respiratory depression.
    Entacapone: (Moderate) Concomitant use of opiate agonists with other central nervous system (CNS) depressants such as COMT inhibitors can potentiate the effects of the opiate and may lead to additive CNS or respiratory depression, profound sedation, or coma. Prior to concurrent use of an opiate 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 the opiate 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.
    Enzalutamide: (Moderate) Monitor for reduced efficacy of oxycodone and signs of opioid withdrawal if coadministration with enzalutamide is necessary; consider increasing the dose of oxycodone as needed. If enzalutamide is discontinued, consider a dose reduction of oxycodone and frequently monitor for signs or respiratory depression and sedation. Oxycodone is a CYP3A4 substrate and enzalutamide is a strong CYP3A4 inducer. Concomitant use with CYP3A4 inducers can decrease oxycodone levels; this may result in decreased efficacy or onset of a withdrawal syndrome in patients who have developed physical dependence.
    Eprosartan; Hydrochlorothiazide, HCTZ: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Erythromycin: (Major) Oxycodone is metabolized by CYP3A4. Concomitant administration of a CYP3A4 inhibitor, such as erythromycin, may cause an increase in oxycodone plasma concentrations, which could increase or prolong adverse effects and may cause potentially fatal respiratory depression. If coadministration of these agents is necessary, patients should be monitored for an extended period of time and dosage adjustments made if warranted.
    Erythromycin; Sulfisoxazole: (Major) Oxycodone is metabolized by CYP3A4. Concomitant administration of a CYP3A4 inhibitor, such as erythromycin, may cause an increase in oxycodone plasma concentrations, which could increase or prolong adverse effects and may cause potentially fatal respiratory depression. If coadministration of these agents is necessary, patients should be monitored for an extended period of time and dosage adjustments made if warranted.
    Escitalopram: (Moderate) The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment. Discontinue the suspected drugs if serotonin syndrome is suspected and manage cliinically. There has been a case report of possible serotonin syndrome caused by the combination of oxycodone and selective serotonin reuptake inhbitors (SSRIs).
    Eslicarbazepine: (Moderate) In vivo studies suggest eslicarbazepine is an inducer of CYP3A4. Oxycodone is metabolized by CYP3A4. Coadministration may cause increased clearance of oxycodone, which could result in lack of efficacy or the development of an abstinence syndrome in a patient who had developed physical dependence to oxycodone. If coadministration of these agents is necessary, monitor patients at frequent intervals and consider dose adjustments if needed.
    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 oxycodone is initiated in a patient taking a benzodiazepine, reduce dosages and titrate to clinical response. For acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours, and for other oxycodone products, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. 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.
    Eszopiclone: (Moderate) Concomitant use of oxycodone with eszopiclone may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. In addition, the risk of next-day psychomotor impairment is increased during co-administration of eszopiclone and other CNS depressants, which may decrease the ability to perform tasks requiring full mental alertness such as driving. 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. If eszopiclone is used concurrently with oxycodone, a reduced dosage of oxycodone and/or eszopiclone is recommended; use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor for sedation and respiratory depression.
    Ethanol: (Major) Alcohol is associated with CNS depression. The combined use of alcohol and CNS depressants can lead to additive CNS depression, which could be dangerous in tasks requiring mental alertness and fatal in overdose. Alcohol taken with other CNS depressants can lead to additive respiratory depression, hypotension, profound sedation, or coma. Consider the patient's use of alcohol or illicit drugs when prescribing CNS depressant medications. In many cases, the patient should receive a lower dose of the CNS depressant initially if the patient is not likely to be compliant with avoiding alcohol. (Major) The risk of developing hepatotoxicity from acetaminophen appears to be increased in patients who regularly consume ethanol. Acute or chronic ethanol use increases acetaminophen-induced hepatotoxicity by inducing cytochrome P450 CYP 2E1 leading to increased formation of the hepatotoxic metabolite of acetaminophen. Also, chronic alcohol use can deplete liver glutathione stores. Administration of acetaminophen should be limited or avoided altogether in patients with alcoholism or patients who consume ethanol regularly.
    Ethinyl Estradiol: (Moderate) Acetaminophen may increase plasma ethinyl estradiol levels, possibly by inhibition of conjugation. Patients taking acetaminophen concomitantly may experience an increase in estrogen related side effects.
    Ethinyl Estradiol; Desogestrel: (Moderate) Acetaminophen may increase plasma ethinyl estradiol levels, possibly by inhibition of conjugation. Patients taking acetaminophen concomitantly may experience an increase in estrogen related side effects.
    Ethinyl Estradiol; Ethynodiol Diacetate: (Moderate) Acetaminophen may increase plasma ethinyl estradiol levels, possibly by inhibition of conjugation. Patients taking acetaminophen concomitantly may experience an increase in estrogen related side effects.
    Ethinyl Estradiol; Etonogestrel: (Moderate) Acetaminophen may increase plasma ethinyl estradiol levels, possibly by inhibition of conjugation. Patients taking acetaminophen concomitantly may experience an increase in estrogen related side effects.
    Ethinyl Estradiol; Levonorgestrel: (Moderate) Acetaminophen may increase plasma ethinyl estradiol levels, possibly by inhibition of conjugation. Patients taking acetaminophen concomitantly may experience an increase in estrogen related side effects.
    Ethinyl Estradiol; Levonorgestrel; Folic Acid; Levomefolate: (Moderate) Acetaminophen may increase plasma ethinyl estradiol levels, possibly by inhibition of conjugation. Patients taking acetaminophen concomitantly may experience an increase in estrogen related side effects.
    Ethinyl Estradiol; Norelgestromin: (Moderate) Acetaminophen may increase plasma ethinyl estradiol levels, possibly by inhibition of conjugation. Patients taking acetaminophen concomitantly may experience an increase in estrogen related side effects.
    Ethinyl Estradiol; Norethindrone Acetate: (Moderate) Acetaminophen may increase plasma ethinyl estradiol levels, possibly by inhibition of conjugation. Patients taking acetaminophen concomitantly may experience an increase in estrogen related side effects.
    Ethinyl Estradiol; Norethindrone Acetate; Ferrous fumarate: (Moderate) Acetaminophen may increase plasma ethinyl estradiol levels, possibly by inhibition of conjugation. Patients taking acetaminophen concomitantly may experience an increase in estrogen related side effects.
    Ethinyl Estradiol; Norethindrone: (Moderate) Acetaminophen may increase plasma ethinyl estradiol levels, possibly by inhibition of conjugation. Patients taking acetaminophen concomitantly may experience an increase in estrogen related side effects.
    Ethinyl Estradiol; Norethindrone; Ferrous fumarate: (Moderate) Acetaminophen may increase plasma ethinyl estradiol levels, possibly by inhibition of conjugation. Patients taking acetaminophen concomitantly may experience an increase in estrogen related side effects.
    Ethinyl Estradiol; Norgestimate: (Moderate) Acetaminophen may increase plasma ethinyl estradiol levels, possibly by inhibition of conjugation. Patients taking acetaminophen concomitantly may experience an increase in estrogen related side effects.
    Ethinyl Estradiol; Norgestrel: (Moderate) Acetaminophen may increase plasma ethinyl estradiol levels, possibly by inhibition of conjugation. Patients taking acetaminophen concomitantly may experience an increase in estrogen related side effects.
    Ethotoin: (Moderate) Oxycodone is metabolized by CYP3A4. Phenytoin or fosphenytoin, an inducer of CYP3A4, may cause increased clearance of oxycodone, which could result in lack of efficacy or the development of an abstinence syndrome in a patient who had developed physical dependence to oxycodone. If coadministration of these agents is necessary, monitor patients at frequent intervals and consider dose adjustments if needed.
    Etomidate: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as general anesthetics, can lead to additive respiratory depression, hypotension, profound sedation, or coma. 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone 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. Monitor patients for sedation and respiratory depression.
    Everolimus: (Moderate) Frequently monitor for respiratory depression and sedation if concurrent use of everolimus is necessary; consider reducing the dose of oxycodone if clinically appropriate. If everolimus is discontinued, monitor for evidence of opioid withdrawal; consider increasing the oxycodone dose if needed. Oxycodone is a CYP3A4 substrate, and coadministration with weak CYP3A4 inhibitors like everolimus can increase oxycodone exposure resulting in increased or prolonged opioid effects including fatal respiratory depression, particularly when an inhibitor is added to a stable dose of oxycodone. If everolimus is discontinued, oxycodone plasma concentrations may decrease resulting in reduced efficacy of the opioid and potential withdrawal syndrome in a patient who has developed physical dependence to oxycodone.
    Exenatide: (Minor) Although an interaction is possible, these drugs may be used together. To avoid potential pharmacokinetic interactions that might alter effectiveness of acetaminophen, it may be advisable for patients to take acetaminophen at least 1 hour prior to an exenatide injection. When 1,000 mg acetaminophen elixir was given with 10 mcg exenatide (at 0 hours) and at 1, 2 and 4 hours after exenatide injection, acetaminophen AUCs were decreased by 21%, 23%, 24%, and 14%, respectively; Cmax was decreased by 37%, 56%, 54%, and 41%, respectively. Additionally, acetaminophen Tmax was delayed from 0.6 hours in the control period to 0.9, 4.2, 3.3, and 1.6 hours, respectively. Acetaminophen AUC, Cmax, and Tmax were not significantly changed when acetaminophen was given 1 h before exenatide injection. The mechanism of this interaction is not available (although it may be due to delayed gastric emptying from exenatide use) and the clinical impact has not been assessed.
    Fentanyl: (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.
    Flibanserin: (Moderate) The concomitant use of flibanserin with CNS depressants, such as opiate agonists, may increase the risk of CNS depression (e.g., dizziness, somnolence) compared to the use of flibanserin alone. Patients should avoid activities requiring full alertness (e.g., operating machinery or driving) until at least 6 hours after each dose and until they know how flibanserin affects them.
    Fluconazole: (Moderate) Concomitant use of oxycodone with fluconazole may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of fluconazole could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If fluconazole is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and fluconazole is a CYP3A4 inhibitor.
    Fluoxetine: (Moderate) The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment. Discontinue the suspected drugs if serotonin syndrome is suspected and manage cliinically. There has been a case report of possible serotonin syndrome caused by the combination of oxycodone and selective serotonin reuptake inhbitors (SSRIs).
    Fluoxetine; Olanzapine: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as olanzapine, can lead to additive respiratory depression, hypotension, profound sedation, or coma. Prior to concurrent use of oxycodone in patients taking olanzapine, 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone at one-third to one-half the usual dosage in patients that are concurrently receiving another CNS depressant. Also, consider using a lower olanzapine dose. Monitor patients for sedation and respiratory depression. (Moderate) The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment. Discontinue the suspected drugs if serotonin syndrome is suspected and manage cliinically. There has been a case report of possible serotonin syndrome caused by the combination of oxycodone and selective serotonin reuptake inhbitors (SSRIs).
    Fluphenazine: (Moderate) Concomitant use of oxycodone with phenothiazines may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Prior to 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. Furthermore, oxycodone is metabolized in part by 2D6 to oxymorphone, which represents < 15% of the total administered dose. Concurrent use of some agents that inhibit CYP2D6 (e.g., quinidine) has not been shown to result in clinically significant interactions. However, many phenothiazines are inhibitors of CYP2D6 (e.g., chlorpromazine, perphenazine, thioridazine) and may potentially increase the effects of oxycodone. Also, severe hypotension may be potentiated with concurrent phenothiazine usage or other drug that compromises vasomotor tone.
    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 oxycodone is initiated in a patient taking a benzodiazepine, reduce dosages and titrate to clinical response. For acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours, and for other oxycodone products, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. 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.
    Fluvoxamine: (Moderate) Concomitant use of oxycodone with fluvoxamine may increase oxycodone 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 oxycodone until stable drug effects are achieved. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has also resulted in serotonin syndrome. If use is warranted, carefully observe the patient, particularly during drug initiation and dose adjustment; discontinue the drugs if serotonin syndrome occurs. Discontinuation of fluvoxamine may cause a reduction in oxycodone plasma concentrations and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. Oxycodone is a substrate for CYP3A4 and fluvoxamine is a CYP3A4 inhibitor.
    Fosamprenavir: (Moderate) Concomitant use of oxycodone with fosamprenavir may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of fosamprenavir could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If fosamprenavir is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and fosamprenavir is a CYP3A4 inhibitor.
    Fosinopril; Hydrochlorothiazide, HCTZ: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Fosphenytoin: (Moderate) Oxycodone is metabolized by CYP3A4. Phenytoin or fosphenytoin, an inducer of CYP3A4, may cause increased clearance of oxycodone, which could result in lack of efficacy or the development of an abstinence syndrome in a patient who had developed physical dependence to oxycodone. If coadministration of these agents is necessary, monitor patients at frequent intervals and consider dose adjustments if needed.
    Fospropofol: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as general anesthetics, can lead to additive respiratory depression, hypotension, profound sedation, or coma. 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone 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. Monitor patients for sedation and respiratory depression.
    Frovatriptan: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as serotonin-receptor agonists. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Gabapentin: (Moderate) Pain medications that contain opiate agonists may intensify CNS depressive adverse effects seen with gabapentin use, such as drowsiness or dizziness. Patients should limit activity until they are aware of how coadministration affects them.
    Gefitinib: (Moderate) Monitor for an increased incidence of oxycodone-related adverse effects if gefitinib and oxycodone are used concomitantly. At high concentrations, gefitinib is an inhibitor of CYP2D6, which is partially responsible for the metabolism of oxycodone. As < 15% of the total administered dose is metabolized by CYP2D6 to oxymorphone, concurrent use of some agents that inhibit CYP2D6 has not been shown to result in clinically significant interactions. However, potent inhibitors of CYP2D6, such as ritonavir, may potentially increase the effects of oxycodone. In patients with solid tumors, exposure to metoprolol, another CYP2D6 substrate, was increased by 30% when given on day 15 of gefitinib dosing (500 mg daily); the effect of gefitinib on CYP2D6-dependent drugs is only likely to be clinically relevant when given with CYP2D6 substrates with a narrow therapeutic index or that are individually dose titrated such as oxycodone.
    General anesthetics: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as general anesthetics, can lead to additive respiratory depression, hypotension, profound sedation, or coma. 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone 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. Monitor patients for sedation and respiratory depression.
    Granisetron: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as serotonin-receptor antagonists. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Grapefruit juice: (Moderate) Patients should not significantly alter their intake of grapefruit or grapefruit juice duing therapy with oxycodone. Grapefruit juice, a CYP3A4 inhibitor, may increase plasma concentrations of oxycodone, a CYP3A4 substrate. This may increase or prolong oxycodone-related toxicities including respiratory depression. Advise patients accordingly; patient monitoring and dosage adjustments may be necessary if grapefruit is consumed regularly.
    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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression.
    Guaifenesin; 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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression.
    Guanabenz: (Moderate) Guanabenz is associated with sedative effects. Guanabenz can potentiate the effects of CNS depressants such as opiate agonists, when administered concomitantly.
    Guanfacine: (Moderate) Central-acting adrenergic agonists like guanfacine have CNS depressive effects and can potentiate the actions of other CNS depressants including opiate agonists.
    Haloperidol: (Moderate) Haloperidol can potentiate the actions of other CNS depressants such as opiate agonists. Caution should be exercised with simultaneous use of these agents due to potential excessive CNS effects.
    Halothane: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as general anesthetics, can lead to additive respiratory depression, hypotension, profound sedation, or coma. 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone 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. Monitor patients for sedation and respiratory depression.
    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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression.
    Hydantoins: (Moderate) Oxycodone is metabolized by CYP3A4. Phenytoin or fosphenytoin, an inducer of CYP3A4, may cause increased clearance of oxycodone, which could result in lack of efficacy or the development of an abstinence syndrome in a patient who had developed physical dependence to oxycodone. If coadministration of these agents is necessary, monitor patients at frequent intervals and consider dose adjustments if needed. (Minor) Hydantoin anticonvulsants induce hepatic microsomal enzymes and may increase the metabolism of other drugs, leading to reduced efficacy of medications like acetaminophen. In addition, the risk of hepatotoxicity from acetaminophen may be increased with the chronic dosing of acetaminophen along with phenytoin. Adhere to recommended acetaminophen dosage limits. Acetaminophen-related hepatotoxicity has occurred clinically with the concurrent use of acetaminophen 1300 mg to 6200 mg daily and phenytoin. Acetaminophen cessation led to serum transaminase normalization within 2 weeks.
    Hydralazine; Hydrochlorothiazide, HCTZ: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Hydrochlorothiazide, HCTZ: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Hydrochlorothiazide, HCTZ; Irbesartan: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Hydrochlorothiazide, HCTZ; Lisinopril: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Hydrochlorothiazide, HCTZ; Losartan: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Hydrochlorothiazide, HCTZ; Methyldopa: (Moderate) Methyldopa is associated with sedative effects. Methyldopa can potentiate the effects of CNS depressants, such as opiate agonists, when administered concomitantly. (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Hydrochlorothiazide, HCTZ; Metoprolol: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Hydrochlorothiazide, HCTZ; Moexipril: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Hydrochlorothiazide, HCTZ; Olmesartan: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Hydrochlorothiazide, HCTZ; Propranolol: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Hydrochlorothiazide, HCTZ; Quinapril: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Hydrochlorothiazide, HCTZ; Spironolactone: (Moderate) Opiate agonists like oxycodone may potentiate orthostatic hypotension when given concomitantly with spironolactone. (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Hydrochlorothiazide, HCTZ; Telmisartan: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Hydrochlorothiazide, HCTZ; Triamterene: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Hydrochlorothiazide, HCTZ; Valsartan: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression.
    Hydrocodone; Ibuprofen: (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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression.
    Hydrocodone; Phenylephrine: (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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression.
    Hydrocodone; Potassium Guaiacolsulfonate: (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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression.
    Hydrocodone; Potassium Guaiacolsulfonate; 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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression.
    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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor patients for sedation and respiratory depression.
    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. Use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. 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.
    Hydroxyprogesterone: (Moderate) In vitro studies indicate that hydroxyprogesterone increases the metabolic rate of CYP2A6 isoenzymes. The metabolism of drugs metabolized by CYP2A6, such as acetaminophen may be increased during treatment with hydroxyprogesterone.
    Hydroxyzine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate; Sodium Biphosphate: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as methylene blue. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Idelalisib: (Major) Avoid concomitant use of idelalisib, a strong CYP3A inhibitor, with oxycodone, a CYP3A substrate, as oxycodone toxicities may be significantly increased. The AUC of a sensitive CYP3A substrate was increased 5.4-fold when coadministered with idelalisib.
    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.
    Imatinib: (Major) Imatinib, STI-571 may affect the metabolism of acetaminophen. In vitro, imatinib was found to inhibit acetaminophen O-glucuronidation at therapeutic levels. Therefore, systemic exposure to acetaminophen is expected to be increased with coadministration of imatinib. Chronic acetaminophen therapy should be avoided in patients receiving imatinib. (Moderate) Imatinib is a potent inhibitor of cytochrome P450 2D6 and may increase concentrations of other drugs metabolized by this enzyme including oxycodone.
    Imipramine: (Moderate) Concomitant use of oxycodone and tricyclic antidepressants (TCAs) may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Orthostasis may occur in ambulatory patients. Constipation occurs with both oxycodone and TCA use. Prior to concurrent use of oxycodone in patients taking a TCA, 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 TCA is used concurrently with oxycodone, a reduced dosage of oxycodone is recommended; use an initial dose of oxycodone at one-third to one-half the usual dosage. Monitor for sedation and respiratory depression and for reduced GI motility. Caution should also be observed when administering TCAs with opiates having serotonergic properties such as oxycodone. Serotonin syndrome may rarely occur and is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma). If serotonin syndrome is suspected, both the TCA and concurrent serotonergic agents should be discontinued.
    Indinavir: (Moderate) Concomitant use of oxycodone with indinavir may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of indinavir could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If indinavir is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and indinavir is a strong CYP3A4 inhibitor.
    Insulin Degludec; Liraglutide: (Minor) Liraglutide did not change the AUC of acetaminophen following a single dose of acetaminophen 1000 mg, administered 8 hours after a dose of liraglutide 1.8 mg at steady state; however, the Cmax of acetaminophen was decreased by 31% and the median Tmax of acetaminophen was delayed up to 15 minutes. The mechanism of the interaction is not known, nor is the clinical significance of this potential interaction. If acetaminophen and liraglutide are co-prescribed, it may be prudent to initially monitor the patient for altered acetaminophen effect.
    Insulin Glargine; Lixisenatide: (Minor) When 1,000 mg acetaminophen was given 1 or 4 hours after 10 mcg lixisenatide, the AUC was not significantly changed, but the acetaminophen Cmax was decreased by 29% and 31%, respectively and median Tmax was delayed by 2 and 1.75 hours, respectively. Acetaminophen AUC, Cmax, and Tmax were not significantly changed when acetaminophen was given 1 h before lixisenatide injection. The mechanism of this interaction is not available (although it may be due to delayed gastric emptying) and the clinical impact has not been assessed. To avoid potential pharmacokinetic interactions that might alter effectiveness of acetaminophen, it may be advisable for patients to take acetaminophen at least one hour prior to lixisenatide subcutaneous injection.
    Isavuconazonium: (Moderate) Coadministration of isavuconazonium, a CYP3A4 inhibitor and substrate, and oxycodone, a CYP3A4 substrate, may increase oxycodone plasma concentrations and increase or prolong related toxicities including potentially fatal respiratory depression. If therapy with both agents is necessary, monitor patient for an extended period of time and adjust dosage as necessary; oxycodone dosage adjustments may be needed if the CYP3A4 inhibitor is discontinued. Concurrent administration of oxycodone and voriconazole, another CYP3A4 inhibitor, increased oxycodone AUC by 3.6-fold and the Cmax by 1.7-fold. (Moderate) Concomitant use of isavuconazonium with acetaminophen may result in increased serum concentrations of acetaminophen. Acetaminophen is a substrate of the hepatic isoenzyme CYP3A4; isavuconazole, the active moiety of isavuconazonium, is a moderate inhibitor of this enzyme. Caution and close monitoring are advised if these drugs are used together.
    Isoflurane: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as general anesthetics, can lead to additive respiratory depression, hypotension, profound sedation, or coma. 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone 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. Monitor patients for sedation and respiratory depression.
    Isoniazid, INH: (Major) Agents which induce the hepatic isoenzyme CYP2E1, such as isoniazid, may potentially increase the risk for acetaminophen-induced hepatotoxicity via generation of a greater percentage of acetaminophen's hepatotoxic metabolites. The combination of isoniazid and acetaminophen has caused severe hepatotoxicity in at least one patient; studies in rats have demonstrated that pre-treatment with isoniazid potentiates acetaminophen hepatotoxicity. (Moderate) Concomitant use of oxycodone with isoniazid may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of isoniazid could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If isoniazid is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and isoniazid is a CYP3A4 inhibitor.
    Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Major) Agents which induce the hepatic isoenzyme CYP2E1, such as isoniazid, may potentially increase the risk for acetaminophen-induced hepatotoxicity via generation of a greater percentage of acetaminophen's hepatotoxic metabolites. The combination of isoniazid and acetaminophen has caused severe hepatotoxicity in at least one patient; studies in rats have demonstrated that pre-treatment with isoniazid potentiates acetaminophen hepatotoxicity. (Moderate) Agents which induce the hepatic isoenzymes CYP2E1 and CYP1A2, such as rifampin, may potentially increase the risk for acetaminophen-induced hepatotoxicity via generation of a greater percentage of acetaminophen's hepatotoxic metabolites. (Moderate) Coadministration of oxycodone, a CYP3A4 substrate, with rifampin, a CYP3A4 inducer, may cause increased clearance of oxycodone, which could result in lack of efficacy or the development of an abstinence syndrome in a patient who had developed physical dependence to oxycodone. Coadministration of rifampin and oxycodone decreased oxycodone AUC by 86% and the Cmax by 63%. If coadministration of these agents is necessary, monitor patients at frequent intervals and consider dose adjustments if needed. In addition, oxycodone is metabolized in part by CYP2D6 to oxymorphone, which represents < 15% of the total administered dose. An inducer of CYP2D6, such as rifampin, could convert a greater percentage of the dose to oxymorphone, which has analgesic activity. In the presence of a CYP2D6 inducer, more oxycodone could be converted to oxymorphone. Also, conversion of oxycodone to noroxycodone may be enhanced. Noroxycodone is reported to be a considerably weaker analgesic than oxycodone. Monitor the patient for excessive adverse effects of oxycodone or reduced efficacy of oxycodone. A lower or higher oxycodone dose may be needed if used with rifampin. (Moderate) Concomitant use of oxycodone with isoniazid may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of isoniazid could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If isoniazid is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and isoniazid is a CYP3A4 inhibitor.
    Isoniazid, INH; Rifampin: (Major) Agents which induce the hepatic isoenzyme CYP2E1, such as isoniazid, may potentially increase the risk for acetaminophen-induced hepatotoxicity via generation of a greater percentage of acetaminophen's hepatotoxic metabolites. The combination of isoniazid and acetaminophen has caused severe hepatotoxicity in at least one patient; studies in rats have demonstrated that pre-treatment with isoniazid potentiates acetaminophen hepatotoxicity. (Moderate) Agents which induce the hepatic isoenzymes CYP2E1 and CYP1A2, such as rifampin, may potentially increase the risk for acetaminophen-induced hepatotoxicity via generation of a greater percentage of acetaminophen's hepatotoxic metabolites. (Moderate) Coadministration of oxycodone, a CYP3A4 substrate, with rifampin, a CYP3A4 inducer, may cause increased clearance of oxycodone, which could result in lack of efficacy or the development of an abstinence syndrome in a patient who had developed physical dependence to oxycodone. Coadministration of rifampin and oxycodone decreased oxycodone AUC by 86% and the Cmax by 63%. If coadministration of these agents is necessary, monitor patients at frequent intervals and consider dose adjustments if needed. In addition, oxycodone is metabolized in part by CYP2D6 to oxymorphone, which represents < 15% of the total administered dose. An inducer of CYP2D6, such as rifampin, could convert a greater percentage of the dose to oxymorphone, which has analgesic activity. In the presence of a CYP2D6 inducer, more oxycodone could be converted to oxymorphone. Also, conversion of oxycodone to noroxycodone may be enhanced. Noroxycodone is reported to be a considerably weaker analgesic than oxycodone. Monitor the patient for excessive adverse effects of oxycodone or reduced efficacy of oxycodone. A lower or higher oxycodone dose may be needed if used with rifampin. (Moderate) Concomitant use of oxycodone with isoniazid may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of isoniazid could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If isoniazid is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and isoniazid is a CYP3A4 inhibitor.
    Itraconazole: (Moderate) Concomitant use of oxycodone with itraconazole may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of itraconazole could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If itraconazole is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and itraconazole is a CYP3A4 inhibitor.
    Ivacaftor: (Minor) Use caution when administering ivacaftor and oxycodone concurrently. Ivacaftor is an inhibitor of CYP3A and oxycodone is partially metabolized by CYP3A. Co-administration of ivacaftor with CYP3A substrates, such as oxycodone, can theoretically increase oxycodone exposure leading to increased or prolonged therapeutic effects and adverse events; however, the clinical impact of this has not yet been determined.
    Ketamine: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as general anesthetics, can lead to additive respiratory depression, hypotension, profound sedation, or coma. 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone 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. Monitor patients for sedation and respiratory depression.
    Ketoconazole: (Major) Oxycodone is metabolized by CYP3A4. Concomitant administration of a CYP3A4 inhibitor, such as ketoconazole, may cause an increase in oxycodone plasma concentrations, which could increase or prolong adverse effects and may cause potentially fatal respiratory depression. If coadministration of these agents is necessary, patients should be monitored for an extended period of time and dosage adjustments made if warranted.
    Lactobacillus: (Moderate) Concurrent use of antidiarrheals and opiate agonists, can lead to severe constipation and possibly additive CNS depression. 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.
    Lamivudine, 3TC; Zidovudine, ZDV: (Minor) Both acetaminophen and zidovudine, ZDV undergo glucuronidation. Competition for the metabolic pathway is thought to have caused a case of acetaminophen-related hepatotoxicity. This interaction may be more clinically significant in patients with depleted glutathione stores, such as patients with acquired immunodeficiency syndrome, poor nutrition, or alcoholism.
    Lamotrigine: (Major) Acetaminophen can be hepatotoxic, and lamotrigine appears to be a potential cause of progressive and fatal hepatotoxicity despite drug discontinuation. A 35 year-old developed fulminant liver failure possibly caused by lamotrigine. She was taking several other drugs including acetaminophen. In a randomized, single-dose study, the serum half-life of lamotrigine after a 300 mg dose decreased by 15% and the area under the plasma concentration-time curve decreased by 20% when given with acetaminophen 900 mg 3 times a day as compared with administration of lamotrigine with placebo. As the lamotrigine maximum serum concentration (Cmax) and time to Cmax was similar between the groups, and the lamotrigine renal clearance increased by 7%, acetaminophen appears to enhance removal of lamotrigine from the circulation.
    Lanthanum Carbonate: (Minor) The manufacturer recommends that oral compounds known to interact with antacids, such as acetaminophen, should not be taken within 2 hours of dosing with lanthanum carbonate.
    Lapatinib: (Major) Coadministration of lapatinib, a CYP3A4 inhibitor, and oxycodone, a CYP3A4 substrate, may increase oxycodone plasma concentrations and increase or prolong related toxicities including potentially fatal respiratory depression. If therapy with both agents is necessary, monitor patient for an extended period of time and adjust dosage as necessary; oxycodone dosage adjustments may be needed if the CYP3A4 inhibitor is discontinued. Concurrent administration of oxycodone and voriconazole, another CYP3A4 inhibitor, increased oxycodone AUC by 3.6-fold and the Cmax by 1.7-fold.
    Levobupivacaine: (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 will 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.
    Levocetirizine: (Moderate) Additive drowsiness may occur if cetirizine or levocetirizine is administered with other drugs that depress the CNS, including opiate agonists.
    Levorphanol: (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.
    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 will 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.
    Lincosamides: (Moderate) Lincosamides, which have been shown to exhibit neuromuscular blocking action, can enhance the effects of opiate agonists if used concomitantly, enhancing respiratory depressant effects. They should be used together with caution and the patient carefully monitored.
    Linezolid: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as linezolid. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Liraglutide: (Minor) Liraglutide did not change the AUC of acetaminophen following a single dose of acetaminophen 1000 mg, administered 8 hours after a dose of liraglutide 1.8 mg at steady state; however, the Cmax of acetaminophen was decreased by 31% and the median Tmax of acetaminophen was delayed up to 15 minutes. The mechanism of the interaction is not known, nor is the clinical significance of this potential interaction. If acetaminophen and liraglutide are co-prescribed, it may be prudent to initially monitor the patient for altered acetaminophen effect.
    Lixisenatide: (Minor) When 1,000 mg acetaminophen was given 1 or 4 hours after 10 mcg lixisenatide, the AUC was not significantly changed, but the acetaminophen Cmax was decreased by 29% and 31%, respectively and median Tmax was delayed by 2 and 1.75 hours, respectively. Acetaminophen AUC, Cmax, and Tmax were not significantly changed when acetaminophen was given 1 h before lixisenatide injection. The mechanism of this interaction is not available (although it may be due to delayed gastric emptying) and the clinical impact has not been assessed. To avoid potential pharmacokinetic interactions that might alter effectiveness of acetaminophen, it may be advisable for patients to take acetaminophen at least one hour prior to lixisenatide subcutaneous injection.
    Lomitapide: (Moderate) Caution should be exercised when lomitapide is used with other medications known to have potential for hepatotoxicity, such as acetaminophen (> 4 g/day PO for >= 3 days/week). The effect of concomitant administration of lomitapide with other hepatotoxic medications is unknown. More frequent monitoring of liver-related tests may be warranted.
    Loperamide: (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. Concurrent use of selected antidiarrheals (e.g., loperamide, diphenoxylate) and opiate agonists can lead to additive CNS depression.
    Loperamide; Simethicone: (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. Concurrent use of selected antidiarrheals (e.g., loperamide, diphenoxylate) and opiate agonists can lead to additive CNS depression.
    Lopinavir; Ritonavir: (Major) Oxycodone is metabolized by CYP3A4. Concomitant administration of ritonavir, a CYP3A4 inhibitor, may cause an increase in oxycodone plasma concentrations, which could increase or prolong adverse effects and may cause potentially fatal respiratory depression. If coadministration of these agents is necessary, patients should be monitored for an extended period and dosage adjustments made if warranted. In addition, oxycodone is metabolized in part by CYP2D6 to oxymorphone, which represents less than 15% of the total administered dose. Concurrent use of some agents that inhibit CYP2D6 has not been shown to result in clinically significant interactions. However, potent inhibitors of CYP2D6, such as ritonavir, may potentially increase the effects of oxycodone. Caution and close monitoring are advised if these drugs are administered together. Initiate oxycodone at low dosages and titrate carefully. (Moderate) Concurrent administration of acetaminophen with ritonavir may result in elevated acetaminophen plasma concentrations and subsequent adverse events. Acetaminophen is metabolized by the hepatic isoenzyme CYP3A4; ritonavir is an inhibitor of this enzyme. Caution and close monitoring are advised if these drugs are administered together.
    Loratadine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as opiate agonists.
    Loratadine; Pseudoephedrine: (Minor) Although loratadine is considered a 'non-sedating' antihistamine, dose-related sedation has been noted. For this reason, it would be prudent to monitor for drowsiness during concurrent use of loratadine with CNS depressants such as opiate agonists.
    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 oxycodone is initiated in a patient taking a benzodiazepine, reduce dosages and titrate to clinical response. For acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours, and for other oxycodone products, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. 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.
    Loxapine: (Moderate) Loxapine can potentiate the actions of other CNS depressants such as opiate agonists. Caution should be exercised with simultaneous use of these agents due to potential excessive CNS effects.
    Lumacaftor; Ivacaftor: (Minor) Use caution when administering ivacaftor and oxycodone concurrently. Ivacaftor is an inhibitor of CYP3A and oxycodone is partially metabolized by CYP3A. Co-administration of ivacaftor with CYP3A substrates, such as oxycodone, can theoretically increase oxycodone exposure leading to increased or prolonged therapeutic effects and adverse events; however, the clinical impact of this has not yet been determined.
    Lumacaftor; Ivacaftor: (Moderate) Lumacaftor; ivacaftor may induce the metabolism of oxycodone, which could result in lack of therapeutic efficacy or the development of an abstinence syndrome in patients who are physically dependent on opioids. If coadministration is necessary, monitor the patient closely at frequent intervals for appropriate pain control and signs of opioid withdrawal. Consider oxycodone dosage adjustments until stable drug effects are achieved. If lumacaftor; ivacaftor is subsequently discontinued, oxycodone plasma concentrations will increase. Monitor the patient closely at frequent intervals for oversedation and respiratory depression and reduce the oxycodone dosage as appropriate. Oxycodone is primarily metabolized by CYP3A4, and lumacaftor is a strong CYP3A inducer. Coadministration of oxycodone with rifampin, another strong CYP3A inducer, resulted in an 86% and 63% decrease in oxycodone AUC and Cmax, respectively, during drug-interaction studies.
    Lurasidone: (Moderate) Due to the CNS effects of lurasidone, caution should be used when lurasidone is given in combination with other centrally acting medications such as opiate agonists.
    Magnesium Salicylate: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. Although salicylates are rarely associated with nephrotoxicity, high-dose, chronic administration of salicylates combined other analgesics, including acetaminophen, significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Additive hepatic toxicity may occur, especially in combined overdose situations. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Magnesium Salts: (Minor) 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.
    Maprotiline: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as maprotiline, can lead to additive respiratory depression, hypotension, profound sedation, or coma. Prior to concurrent use of oxycodone in patients taking maprotiline, 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone at one-third to one-half the usual dosage in patients that are concurrently receiving another CNS depressant. Also consider using a lower maprotiline dose. Monitor patients for sedation and respiratory depression.
    Meclizine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Meperidine: (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.
    Meperidine; Promethazine: (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.
    Mephobarbital: (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    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 will 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.
    Mepivacaine; Levonordefrin: (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 will 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: (Moderate) Concomitant use of oxycodone with meprobamate may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. 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. If meprobamate is used concurrently with oxycodone, a reduced dosage of oxycodone and/or meprobamate is recommended; use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor for sedation and respiratory depression.
    Mesoridazine: (Moderate) Concomitant use of oxycodone with phenothiazines may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Prior to 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. Furthermore, oxycodone is metabolized in part by 2D6 to oxymorphone, which represents < 15% of the total administered dose. Concurrent use of some agents that inhibit CYP2D6 (e.g., quinidine) has not been shown to result in clinically significant interactions. However, many phenothiazines are inhibitors of CYP2D6 (e.g., chlorpromazine, perphenazine, thioridazine) and may potentially increase the effects of oxycodone. Also, severe hypotension may be potentiated with concurrent phenothiazine usage or other drug that compromises vasomotor tone.
    Metaxalone: (Major) Concomitant use of opiate agonists with skeletal muscle relaxants may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with skeletal muscle relaxants 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 oxycodone or oxycodone; naloxone is initiated in a patient taking a skeletal muscle relaxant, use an initial dose of oxycodone at one-third to one-half the usual dosage and titrate to clinical response; reduced initial doses of oxycodone; naltrexone, aspirin, ASA; oxycodone, and ibuprofen; oxycodone are also recommended. If a decision is made to start treatment with acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours. If a skeletal muscle relaxant is prescribed for a patient taking an opiate agonist, use a lower initial dose of the skeletal muscle relaxant and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
    Methadone: (Major) Concomitant use of methadone with another CNS depressant, such as oxycodone, 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; in opioid-naive adults, use an initial methadone dose of 2.5 mg every 12 hours. Also, consider a using a lower dose of the CNS depressant; use an initial dose of oxycodone at one-third to one-half the usual dosage. Monitor patients for sedation and respiratory depression.
    Methenamine; Sodium Acid Phosphate; Methylene Blue; Hyoscyamine: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as methylene blue. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Methocarbamol: (Major) Concomitant use of opiate agonists with skeletal muscle relaxants may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with skeletal muscle relaxants 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 oxycodone or oxycodone; naloxone is initiated in a patient taking a skeletal muscle relaxant, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage and titrate to clinical response; reduced initial doses of oxycodone; naltrexone, aspirin, ASA; oxycodone, and ibuprofen; oxycodone are also recommended. If a decision is made to start treatment with acetaminophen; oxycodone extended-release tabIets, start with 1 tablet PO every 12 hours. If a skeletal muscle relaxant is prescribed for a patient taking an opiate agonist, use a lower initial dose of the skeletal muscle relaxant and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
    Methohexital: (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    Methyclothiazide: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Methyldopa: (Moderate) Methyldopa is associated with sedative effects. Methyldopa can potentiate the effects of CNS depressants, such as opiate agonists, when administered concomitantly.
    Methylene Blue: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as methylene blue. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Metoclopramide: (Moderate) Opiate agonists antagonize GI motility and can decrease the gastroprokinetic effects of metoclopramide.
    Metolazone: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Metyrapone: (Major) Coadministration of metyrapone and acetaminophen may result in acetaminophen toxicity. Acetaminophen glucuronidation is inhibited by metyrapone. It may be advisable for patients to avoid acetaminophen while taking metyrapone. (Moderate) Metyrapone may cause dizziness and/or drowsiness. Other drugs that may also cause drowsiness, such as opiate agonists, should be used with caution. Additive drowsiness and/or dizziness is possible. Also, hydrocodone is metabolized by CYP3A4. Metyrapone, an inducer of CYP3A4, may cause increased clearance of hydrocodone, which could result in lack of efficacy or the development of an abstinence syndrome in a patient who had developed physical dependence to hydrocodone. Monitor the patient for reduced efficacy of hydrocodone. A higher hydrocodone dose may be needed if used with metyrapone.
    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 oxycodone is initiated in a patient taking a benzodiazepine, reduce dosages and titrate to clinical response. For acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours, and for other oxycodone products, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. 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.
    Mifepristone, RU-486: (Moderate) Concomitant use of oxycodone with mifepristone may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of mifepristone could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If mifepristone is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and mifepristone is a CYP3A4 inhibitor.
    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.
    Mipomersen: (Moderate) Caution should be exercised when mipomersen is used with other medications known to have potential for hepatotoxicity, such as acetaminophen (> 4 g/day for >= 3 days/week). The effect of concomitant administration of mipomersen with other hepatotoxic medications is unknown. More frequent monitoring of liver-related tests may be warranted.
    Mirabegron: (Moderate) Mirabegron is a moderate CYP2D6 inhibitor. Exposure of drugs partially metabolized by CYP2D6, such as oxycodone, may be increased when co-administered with mirabegron. Therefore, appropriate monitoring and dose adjustment may be necessary.
    Mirtazapine: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as mirtazapine, can lead to additive respiratory depression, hypotension, profound sedation, or coma. Prior to concurrent use of oxycodone in patients taking mirtazapine, 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone at one-third too one-half the usual dosage in patients that are concurrently receiving another CNS depressant. Also consider using a lower mirtazapine dose. Monitor patients for sedation and respiratory depression.
    Mitotane: (Major) Use caution if mitotane and oxycodone are used concomitantly, and monitor for decreased efficacy of oxycodone, a possible change in dosage requirements, and possible development of an abstinence syndrome in a patient with physical dependence to oxycodone. Mitotane is a strong CYP3A4 inducer and oxycodone is a CYP3A4 substrate; coadministration may result in decreased plasma concentrations of oxycodone. Coadministration of rifampin and oxycodone decreased oxycodone AUC by 86% and the Cmax by 63%. (Minor) Use caution if mitotane and acetaminophen are used concomitantly, and monitor for decreased efficacy of acetaminophen. Mitotane is a strong CYP3A4 inducer and acetaminophen is a minor (10% to 15%) CYP3A4 substrate; coadministration may result in decreased plasma concentrations of acetaminophen.
    Mivacurium: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as neuromuscular blockers, can potentiate the effects of alfentanil on respiration, alertness, and blood pressure. A dose reduction of one or both drugs may be warranted.
    Molindone: (Moderate) Concomitant use of opiate agonists with other central nervous system (CNS) depressants, such as molindone, can potentiate the effects of the opiate and may lead to additive CNS or respiratory depression, profound sedation, or coma. Prior to concurrent use of an opiate 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 the opiate and/or molindone 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.
    Monoamine oxidase inhibitors: (Major) Concomitant use of oxycodone with other CNS depressants, such as MAOIs, can lead to additive respiratory or CNS depression, hypotension, profound sedation, or coma. 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. Initiate oxycodone at one-third to one-half the usual dosage in patients that are concurrently receiving another CNS depressant. Also consider using a lower dose of the CNS depressant. Monitor patients for sedation and respiratory depression. Advise patients against driving or performing other tasks requiring alertness until they know how the combination affects them.
    Morphine: (Major) Concomitant use of oxycodone with morphine may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may 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 oxycodone and/or morphine is recommended; use an initial dose of oxycodone at one-third to one-half the usual dosage. 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 for sedation and respiratory depression.
    Morphine; Naltrexone: (Major) Concomitant use of oxycodone with morphine may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may 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 oxycodone and/or morphine is recommended; use an initial dose of oxycodone at one-third to one-half the usual dosage. 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 for sedation and respiratory depression.
    Nabilone: (Moderate) Concomitant use of opiate agonists with other central nervous system (CNS) depressants, such as nabilone, can potentiate the effects of the opiate and may lead to additive CNS or respiratory depression, profound sedation, or coma. Prior to concurrent use of an opiate 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 the opiate 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.
    Nalbuphine: (Major) Avoid the concomitant use of nalbuphine and opiate agonists, such as oxycodone. Nalbuphine is a mixed opiate agonist/antagonist that may block the effects of opiate agonists and reduce analgesic effects of acetaminophen; oxycodone. Nalbuphine may cause withdrawal symptoms in patients receiving chronic opiate agonists. Concurrent use of nalbuphine 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.
    Naloxone: (Major) Naloxone can antagonize the therapeutic efficacy of oxycodone in addition to precipitating withdrawal symptoms in patients who are physically dependent on opiate drugs including oxycodone.
    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. 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; Sumatriptan: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as serotonin-receptor agonists. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Naratriptan: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as serotonin-receptor agonists. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Nefazodone: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as nefazodone, can lead to additive respiratory depression, hypotension, profound sedation, or coma. Prior to concurrent use of oxycodone in patients taking nefazodone, 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone at one-third to one-half the usual dosage in patients that are concurrently receiving another CNS depressant. Also, consider using a lower nefazodone dose. Monitor patients for sedation and respiratory depression.
    Nesiritide, BNP: (Major) The potential for hypotension may be increased when coadministering nesiritide with opiate agonists.
    Netupitant; Palonosetron: (Moderate) Concomitant use of oxycodone with netupitant may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of netupitant could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If netupitant is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and netupitant is a CYP3A4 inhibitor.
    Neuromuscular blockers: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as neuromuscular blockers, can potentiate the effects of alfentanil on respiration, alertness, and blood pressure. A dose reduction of one or both drugs may be warranted.
    Nicardipine: (Moderate) Concomitant use of oxycodone with nicardipine may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of nicardipine could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If nicardipine is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and nicardipine is a CYP3A4 inhibitor.
    Nilotinib: (Major) Concomitant use of nilotinib, a CYP3A4 and CYP2D6 inhibitor, and oxycodone, a CYP3A4 and CYP2D6 substrate, may result in increased oxycodone levels. If these drugs are used together, consider an oxycodone dose reduction and monitor patients for toxicity (e.g., sedation, respiratory depression).
    Nitroglycerin: (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: (Moderate) Concomitant use of oxycodone and tricyclic antidepressants (TCAs) may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Orthostasis may occur in ambulatory patients. Constipation occurs with both oxycodone and TCA use. Prior to concurrent use of oxycodone in patients taking a TCA, 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 TCA is used concurrently with oxycodone, a reduced dosage of oxycodone is recommended; use an initial dose of oxycodone at one-third to one-half the usual dosage. Monitor for sedation and respiratory depression and for reduced GI motility. Caution should also be observed when administering TCAs with opiates having serotonergic properties such as oxycodone. Serotonin syndrome may rarely occur and is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma). If serotonin syndrome is suspected, both the TCA and concurrent serotonergic agents should be discontinued.
    Octreotide: (Major) Octreotide can cause additive constipation with opiate agonists such as oxycodone. 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. Monitor patients during concomitant use. Also, coadministration of octreotide, a CYP3A4 inhibitor, and oxycodone, a CYP3A4 substrate, may increase oxycodone plasma concentrations and increase or prolong related toxicities including potentially fatal respiratory depression. If therapy with both agents is necessary, monitor patient for an extended period of time and adjust dosage as necessary; oxycodone dosage adjustments may be needed if the CYP3A4 inhibitor is discontinued. Concurrent administration of oxycodone and voriconazole, another CYP3A4 inhibitor, increased oxycodone AUC by 3.6-fold and the Cmax by 1.7-fold.
    Olanzapine: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as olanzapine, can lead to additive respiratory depression, hypotension, profound sedation, or coma. Prior to concurrent use of oxycodone in patients taking olanzapine, 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone at one-third to one-half the usual dosage in patients that are concurrently receiving another CNS depressant. Also, consider using a lower olanzapine dose. Monitor patients for sedation and respiratory depression.
    Ombitasvir; Paritaprevir; Ritonavir: (Major) Oxycodone is metabolized by CYP3A4. Concomitant administration of ritonavir, a CYP3A4 inhibitor, may cause an increase in oxycodone plasma concentrations, which could increase or prolong adverse effects and may cause potentially fatal respiratory depression. If coadministration of these agents is necessary, patients should be monitored for an extended period and dosage adjustments made if warranted. In addition, oxycodone is metabolized in part by CYP2D6 to oxymorphone, which represents less than 15% of the total administered dose. Concurrent use of some agents that inhibit CYP2D6 has not been shown to result in clinically significant interactions. However, potent inhibitors of CYP2D6, such as ritonavir, may potentially increase the effects of oxycodone. Caution and close monitoring are advised if these drugs are administered together. Initiate oxycodone at low dosages and titrate carefully. (Moderate) Concurrent administration of acetaminophen with ritonavir may result in elevated acetaminophen plasma concentrations and subsequent adverse events. Acetaminophen is metabolized by the hepatic isoenzyme CYP3A4; ritonavir is an inhibitor of this enzyme. Caution and close monitoring are advised if these drugs are administered together.
    Omeprazole; Sodium Bicarbonate: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
    Ondansetron: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as serotonin-receptor antagonists. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Oritavancin: (Minor) Oxycodone is metabolized by CYP3A4 and CYP2D6; oritavancin is a weak CYP3A4 and CYP2D6 inducer. Plasma concentrations and efficacy of oxycodone may be reduced if these drugs are administered concurrently.
    Orphenadrine: (Major) Concomitant use of opiate agonists with skeletal muscle relaxants may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with skeletal muscle relaxants 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 oxycodone or oxycodone; naloxone is initiated in a patient taking a skeletal muscle relaxant, use an initial dose of oxycodone at one-third to one-half the usual dosage and titrate to clinical response; reduced initial doses of oxycodone; naltrexone, aspirin, ASA; oxycodone, and ibuprofen; oxycodone are also recommended. If a decision is made to start treatment with acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours. If a skeletal muscle relaxant is prescribed for a patient taking an opiate agonist, use a lower initial dose of the skeletal muscle relaxant and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
    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 oxycodone is initiated in a patient taking a benzodiazepine, reduce dosages and titrate to clinical response. For acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours, and for other oxycodone products, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. 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.
    Oxcarbazepine: (Minor) Drugs that induce the hepatic isoenzymes CYP2E1 and CYP1A2, such as oxcarbazepine, may potentially increase the risk for acetaminophen-induced hepatotoxicity via generation of a greater percentage of acetaminophen's hepatotoxic metabolite, NAPQI. Also, the analgesic activity of acetaminophen may be reduced.
    Oxymorphone: (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. a reduced dosage of oxymorphone (1/3 to 1/2 of the usual dose) and/or the CNS depressant is recommended. If the extended-release oxymorphone tablets are used concurrently with a CNS depressant, it is recommended to use an initial dosage of 5 mg PO every 12 hours. Monitor for sedation and respiratory depression.
    Palbociclib: (Moderate) Monitor frequently for an increase in oxycodone-related adverse reactions (e.g., sedation, respiratory depression) if coadministered with palbociclib. Consider dosage reduction of oxycodone until stable drug effects are achieved if concurrent use is necessary. If palbociclib is discontinued, consider an increased dose of oxycodone and monitor for signs of opioid withdrawal. Palbociclib is a weak time-dependent inhibitor of CYP3A and oxycodone is a CYP3A4 substrate.
    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.
    Palonosetron: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as serotonin-receptor antagonists. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Pancuronium: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as neuromuscular blockers, can potentiate the effects of alfentanil on respiration, alertness, and blood pressure. A dose reduction of one or both drugs may be warranted.
    Papaverine: (Moderate) Papaverine is a benzylisoquinoline alkaloid of opium and may have synergistic effects with opiate agonists. Concurrent use of papaverine with potent CNS depressants could lead to enhanced sedation.
    Paroxetine: (Moderate) The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment. Discontinue the suspected drugs if serotonin syndrome is suspected and manage cliinically. There has been a case report of possible serotonin syndrome caused by the combination of oxycodone and selective serotonin reuptake inhbitors (SSRIs).
    Pazopanib: (Moderate) Pazopanib is a weak inhibitor of CYP3A4. Coadministration of pazopanib and oxycodone, a CYP3A4 substrate, may cause an increase in systemic concentrations of oxycodone. Use caution when administering these drugs concomitantly.
    Peginterferon Alfa-2b: (Moderate) Oxycodone is metabolized in part by CYP2D6 to oxymorphone, which represents < 15% of the total administered dose. In theory, concurrent use of a CYP2D6 inhibitor, such as peginterferon alfa-2b, may inhibit the conversion of oxycodone to oxymorphone. In addition, concurrent use with a CYP2D6 inhibitor may increase the adverse effects of oxycodone. Close monitoring for pronounced opioid effects is advisable.
    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.
    Pentazocine: (Major) Avoid the concomitant use of pentazocine and opiate agonists, such as oxycodone. Pentazocine is a mixed opiate agonist/antagonist that may block the effects of opiate agonists and reduce analgesic effects of oxycodone. 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.
    Pentazocine; Naloxone: (Major) Avoid the concomitant use of pentazocine and opiate agonists, such as oxycodone. Pentazocine is a mixed opiate agonist/antagonist that may block the effects of opiate agonists and reduce analgesic effects of oxycodone. 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) Naloxone can antagonize the therapeutic efficacy of oxycodone in addition to precipitating withdrawal symptoms in patients who are physically dependent on opiate drugs including oxycodone.
    Pentobarbital: (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    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 opiate agonists.
    Perphenazine: (Moderate) Concomitant use of oxycodone with phenothiazines may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Prior to 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. Furthermore, oxycodone is metabolized in part by 2D6 to oxymorphone, which represents < 15% of the total administered dose. Concurrent use of some agents that inhibit CYP2D6 (e.g., quinidine) has not been shown to result in clinically significant interactions. However, many phenothiazines are inhibitors of CYP2D6 (e.g., chlorpromazine, perphenazine, thioridazine) and may potentially increase the effects of oxycodone. Also, severe hypotension may be potentiated with concurrent phenothiazine usage or other drug that compromises vasomotor tone.
    Perphenazine; Amitriptyline: (Moderate) Concomitant use of oxycodone and tricyclic antidepressants (TCAs) may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Orthostasis may occur in ambulatory patients. Constipation occurs with both oxycodone and TCA use. Prior to concurrent use of oxycodone in patients taking a TCA, 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 TCA is used concurrently with oxycodone, a reduced dosage of oxycodone is recommended; use an initial dose of oxycodone at one-third to one-half the usual dosage. Monitor for sedation and respiratory depression and for reduced GI motility. Caution should also be observed when administering TCAs with opiates having serotonergic properties such as oxycodone. Serotonin syndrome may rarely occur and is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma). If serotonin syndrome is suspected, both the TCA and concurrent serotonergic agents should be discontinued. (Moderate) Concomitant use of oxycodone with phenothiazines may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Prior to 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. Furthermore, oxycodone is metabolized in part by 2D6 to oxymorphone, which represents < 15% of the total administered dose. Concurrent use of some agents that inhibit CYP2D6 (e.g., quinidine) has not been shown to result in clinically significant interactions. However, many phenothiazines are inhibitors of CYP2D6 (e.g., chlorpromazine, perphenazine, thioridazine) and may potentially increase the effects of oxycodone. Also, severe hypotension may be potentiated with concurrent phenothiazine usage or other drug that compromises vasomotor tone.
    Phenobarbital: (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    Phenothiazines: (Moderate) Concomitant use of oxycodone with phenothiazines may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Prior to 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. Furthermore, oxycodone is metabolized in part by 2D6 to oxymorphone, which represents < 15% of the total administered dose. Concurrent use of some agents that inhibit CYP2D6 (e.g., quinidine) has not been shown to result in clinically significant interactions. However, many phenothiazines are inhibitors of CYP2D6 (e.g., chlorpromazine, perphenazine, thioridazine) and may potentially increase the effects of oxycodone. Also, severe hypotension may be potentiated with concurrent phenothiazine usage or other drug that compromises vasomotor tone.
    Phenytoin: (Moderate) Oxycodone is metabolized by CYP3A4. Phenytoin or fosphenytoin, an inducer of CYP3A4, may cause increased clearance of oxycodone, which could result in lack of efficacy or the development of an abstinence syndrome in a patient who had developed physical dependence to oxycodone. If coadministration of these agents is necessary, monitor patients at frequent intervals and consider dose adjustments if needed.
    Pimozide: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as pimozide, can lead to additive respiratory depression, hypotension, profound sedation, or coma. Prior to concurrent use of oxycodone in patients taking pimozide, 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone at one-third to one-half the usual dosage in patients that are concurrently receiving another CNS depressant. Also, consider using a lower pimozide dose. Monitor patients for sedation and respiratory depression.
    Pneumococcal Vaccine, Polyvalent: (Moderate) Concomitant administration of antipyretics, such as acetaminophen, 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 oxycodone with posaconazole may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of posaconazole could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If posaconazole is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and posaconazole is a CYP3A4 inhibitor. (Moderate) Posaconazole and acetaminophen should be coadministered with caution due to an increased potential for acetaminophen-related adverse events. Posaconazole is a potent inhibitor of CYP3A4, an isoenzyme partially responsible for the metabolism of acetaminophen. These drugs used in combination may result in elevated acetaminophen plasma concentrations, causing an increased risk for acetaminophen-related adverse events.
    Pramipexole: (Moderate) Concomitant use of oxycodone with other CNS depressants like pramipexole can lead to additive respiratory depression, hypotension, profound sedation, or coma. 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone 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. Monitor patients for sedation and respiratory depression.
    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. (Minor) Because pramlintide has the potential to delay the absorption of concomitantly administered medications, medications should be administered at least 1 hour before or 2 hours after pramlintide injection when the rapid onset of a concomitantly administered oral medication is a critical determinant of effectiveness (i.e., analgesics).
    Pregabalin: (Moderate) Concomitant use of opiate agonists with other central nervous system (CNS) depressants can potentiate the effects of the opiate and may lead to additive CNS or respiratory depression, profound sedation, or coma. Examples of drugs associated with CNS depression include pregabalin. Prior to concurrent use of an opiate 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 the opiate 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.
    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 will 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. (Minor) Prilocaine and acetaminophen each individually can cause methemoglobinemia. Patients treated with prilocaine who are receiving acetaminophen concurrently are at greater risk for developing methemoglobinemia.
    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 will 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. (Minor) Prilocaine and acetaminophen each individually can cause methemoglobinemia. Patients treated with prilocaine who are receiving acetaminophen concurrently are at greater risk for developing methemoglobinemia.
    Primidone: (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    Procaine: (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.
    Procarbazine: (Moderate) Opiate agonists may cause additive sedation or other CNS effects when given in combination with procarbazine.
    Prochlorperazine: (Moderate) Concomitant use of oxycodone with phenothiazines may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Prior to 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. Furthermore, oxycodone is metabolized in part by 2D6 to oxymorphone, which represents < 15% of the total administered dose. Concurrent use of some agents that inhibit CYP2D6 (e.g., quinidine) has not been shown to result in clinically significant interactions. However, many phenothiazines are inhibitors of CYP2D6 (e.g., chlorpromazine, perphenazine, thioridazine) and may potentially increase the effects of oxycodone. Also, severe hypotension may be potentiated with concurrent phenothiazine usage or other drug that compromises vasomotor tone.
    Propafenone: (Moderate) Oxycodone is metabolized in part by cytochrome P450 2D6 to oxymorphone, which represents < 15% of the total administered dose. Potent inhibitors of CYP2D6, such as propafenone, may potentially increase the effects of oxycodone; however, such blockade has not been shown to be of clinical significance during oxycodone treatment. Clinicians should be aware of this possible interaction.
    Propofol: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as general anesthetics, can lead to additive respiratory depression, hypotension, profound sedation, or coma. 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone 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. Monitor patients for sedation and respiratory depression.
    Propoxyphene: (Major) Propoxyphene is a weak mu-opiate receptor agonist. As other opiate agonists bind to mu-opiate receptors, concurrent use of an opiate agonist with propoxyphene is not desirable. Also, propoxyphene will only partially suppress the withdrawal syndrome in patients physically dependent on morphine or other narcotics. The choice of one mu-opiate receptor agonist needs to be made to avoid duplicate therapy and possible adverse effects. For example, concomitant use of propoxyphene with other CNS depressants (e.g., other opiate agonists) can potentiate the effects of respiratory depression and/or sedation. Propoxyphene in combination with other CNS depressants is a major cause of drug-related death. Fatalities within the first hour of overdosage are not uncommon. Extreme caution is needed during concomitant use of any CNS-depressant drug and propoxyphene. 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.
    Protriptyline: (Moderate) Concomitant use of oxycodone and tricyclic antidepressants (TCAs) may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Orthostasis may occur in ambulatory patients. Constipation occurs with both oxycodone and TCA use. Prior to concurrent use of oxycodone in patients taking a TCA, 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 TCA is used concurrently with oxycodone, a reduced dosage of oxycodone is recommended; use an initial dose of oxycodone at one-third to one-half the usual dosage. Monitor for sedation and respiratory depression and for reduced GI motility. Caution should also be observed when administering TCAs with opiates having serotonergic properties such as oxycodone. Serotonin syndrome may rarely occur and is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma). If serotonin syndrome is suspected, both the TCA and concurrent serotonergic agents should be discontinued.
    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 oxycodone is initiated in a patient taking a benzodiazepine, reduce dosages and titrate to clinical response. For acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours, and for other oxycodone products, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. 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.
    Quetiapine: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as quetiapine, can lead to additive respiratory depression, hypotension, profound sedation, or coma. Prior to concurrent use of oxycodone in patients taking quetiapine, 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone at one-third to one-half the usual dosage in patients that are concurrently receiving another CNS depressant. Also consider using a lower quetiapine dose. Monitor patients for sedation and respiratory depression.
    Quinidine: (Moderate) Oxycodone is metabolized in part by cytochrome P450 2D6 to oxymorphone, which represents < 15% of the total administered dose. Potent inhibitors of CYP2D6, such as quinidine, may potentially increase the effects of oxycodone; however, such blockade has not been shown to be of clinical significance during oxycodone treatment. Clinicians should be aware of this possible interaction.
    Quinine: (Moderate) Quinine inhibits CYP2D6 and may theoretically increase concentrations of other drugs metabolized by this enzyme. Caution is recommended when administering quinine with other CYP2D6 substrates that have a narrow therapeutic range or where large increases in serum concentrations may be associated with severe adverse reactions including oxycodone.
    Ranolazine: (Moderate) Oxycodone is metabolized in part by cytochrome P450 2D6 to oxymorphone, which represents < 15% of the total administered dose. Ranolazine and/or metabolites partially inhibit CYP2D6 isoenzymes based on data available. Although the concomitant use of ranolazine with oxycodone has not been studied, ranolazine may theoretically increase plasma concentrations of oxycodone, Studies of interactions with other CYP2D6 inhibitors and oxycodone have not demonstrated clinical significance.
    Rapacuronium: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as neuromuscular blockers, can potentiate the effects of alfentanil on respiration, alertness, and blood pressure. A dose reduction of one or both drugs may be warranted.
    Rasagiline: (Moderate) Opiate agonists (e.g., alfentanil, codeine, hydrocodone, morphine, sufentanil, etc.) may cause additive CNS depression, drowsiness, dizziness or hypotension, so use with MAOIs should be cautious; lower initial dosages of the opiate are recommended followed by careful titration.
    Remifentanil: (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.
    Ribociclib: (Moderate) Use caution if coadministration of ribociclib with oxycodone is necessary, as the systemic exposure of oxycodone may be increased resulting in increase in treatment-related adverse reactions including sedation and respiratory depression; adjust the dose of oxycodone if necessary. Ribociclib is a moderate CYP3A4 inhibitor and oxycodone is a CYP3A4 substrate.
    Ribociclib; Letrozole: (Moderate) Use caution if coadministration of ribociclib with oxycodone is necessary, as the systemic exposure of oxycodone may be increased resulting in increase in treatment-related adverse reactions including sedation and respiratory depression; adjust the dose of oxycodone if necessary. Ribociclib is a moderate CYP3A4 inhibitor and oxycodone is a CYP3A4 substrate.
    Rifabutin: (Moderate) As a cytochrome P450 isoenzyme inducers, rifabutin could induce the metabolism of acetaminophen. An increase in acetaminophen-induced hepatotoxicity may be seen by increasing the metabolism of acetaminophen to its toxic metabolite, NAPQI. Also, the analgesic activity of acetaminophen may be reduced.
    Rifampin: (Moderate) Agents which induce the hepatic isoenzymes CYP2E1 and CYP1A2, such as rifampin, may potentially increase the risk for acetaminophen-induced hepatotoxicity via generation of a greater percentage of acetaminophen's hepatotoxic metabolites. (Moderate) Coadministration of oxycodone, a CYP3A4 substrate, with rifampin, a CYP3A4 inducer, may cause increased clearance of oxycodone, which could result in lack of efficacy or the development of an abstinence syndrome in a patient who had developed physical dependence to oxycodone. Coadministration of rifampin and oxycodone decreased oxycodone AUC by 86% and the Cmax by 63%. If coadministration of these agents is necessary, monitor patients at frequent intervals and consider dose adjustments if needed. In addition, oxycodone is metabolized in part by CYP2D6 to oxymorphone, which represents < 15% of the total administered dose. An inducer of CYP2D6, such as rifampin, could convert a greater percentage of the dose to oxymorphone, which has analgesic activity. In the presence of a CYP2D6 inducer, more oxycodone could be converted to oxymorphone. Also, conversion of oxycodone to noroxycodone may be enhanced. Noroxycodone is reported to be a considerably weaker analgesic than oxycodone. Monitor the patient for excessive adverse effects of oxycodone or reduced efficacy of oxycodone. A lower or higher oxycodone dose may be needed if used with rifampin.
    Risperidone: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as risperidone, can lead to additive respiratory depression, hypotension, profound sedation, or coma. Prior to concurrent use of oxycodone in patients taking risperidone, 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone at one-third to one-half the usual dosage in patients that are concurrently receiving another CNS depressant. Also, consider using a lower risperidone dose. Monitor patients for sedation and respiratory depression.
    Ritonavir: (Major) Oxycodone is metabolized by CYP3A4. Concomitant administration of ritonavir, a CYP3A4 inhibitor, may cause an increase in oxycodone plasma concentrations, which could increase or prolong adverse effects and may cause potentially fatal respiratory depression. If coadministration of these agents is necessary, patients should be monitored for an extended period and dosage adjustments made if warranted. In addition, oxycodone is metabolized in part by CYP2D6 to oxymorphone, which represents less than 15% of the total administered dose. Concurrent use of some agents that inhibit CYP2D6 has not been shown to result in clinically significant interactions. However, potent inhibitors of CYP2D6, such as ritonavir, may potentially increase the effects of oxycodone. Caution and close monitoring are advised if these drugs are administered together. Initiate oxycodone at low dosages and titrate carefully. (Moderate) Concurrent administration of acetaminophen with ritonavir may result in elevated acetaminophen plasma concentrations and subsequent adverse events. Acetaminophen is metabolized by the hepatic isoenzyme CYP3A4; ritonavir is an inhibitor of this enzyme. Caution and close monitoring are advised if these drugs are administered together.
    Rizatriptan: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as serotonin-receptor agonists. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Rocuronium: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as neuromuscular blockers, can potentiate the effects of alfentanil on respiration, alertness, and blood pressure. A dose reduction of one or both drugs may be warranted.
    Rolapitant: (Major) Use caution if oxycodone and rolapitant are used concurrently, and monitor for oxycodone-related adverse effects. Oxycodone is a CYP2D6 substrate where an increase in exposure may significantly increase adverse effects, and rolapitant is a moderate CYP2D6 inhibitor; the inhibitory effect of rolapitant lasts for at least 7 days, and may last longer after single dose administration. The Cmax and AUC of another CYP2D6 substrate, dextromethorphan, were increased by 120% and 160%, respectively, on day 1 with rolapitant, and by 180% and 230%, respectively, on day 8 after rolapitant administration.
    Ropinirole: (Moderate) Concomitant use of opiate agonists with other central nervous system (CNS) depressants such as ropinirole can potentiate the effects of the opiate and may lead to additive CNS or respiratory depression, profound sedation, or coma. Prior to concurrent use of an opiate 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 the opiate 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.
    Ropivacaine: (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 will 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.
    Salsalate: (Moderate) Prolonged concurrent use of acetaminophen and salicylates is not recommended. Although salicylates are rarely associated with nephrotoxicity, high-dose, chronic administration of salicylates combined other analgesics, including acetaminophen, significantly increases the risk of analgesic nephropathy, renal papillary necrosis, and end-stage renal disease. Additive hepatic toxicity may occur, especially in combined overdose situations. Do not exceed the recommended individual maximum doses when these agents are given concurrently for short-term therapy.
    Saquinavir: (Moderate) Concomitant use of oxycodone with saquinavir may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of saquinavir could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If saquinavir is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and saquinavir is a CYP3A4 inhibitor.
    Secobarbital: (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    Sedating H1-blockers: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Selective norepinephrine reuptake inhibitors: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as serotonin norepinephrine reuptake inhibitors (SNRIs). Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Serotonin-Receptor Agonists: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as serotonin-receptor agonists. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Serotonin-Receptor Antagonists: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as serotonin-receptor antagonists. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Sertraline: (Moderate) The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. If concomitant use is warranted, carefully observe the patient, particularly during treatment initiation and dose adjustment. Discontinue the suspected drugs if serotonin syndrome is suspected and manage cliinically. There has been a case report of possible serotonin syndrome caused by the combination of oxycodone and selective serotonin reuptake inhbitors (SSRIs).
    Sevoflurane: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as general anesthetics, can lead to additive respiratory depression, hypotension, profound sedation, or coma. 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone 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. Monitor patients for sedation and respiratory depression.
    Sildenafil: (Moderate) Prolonged erections have been reported in two patients taking sildenafil with dihydrocodeine. Although more data are needed, use caution when prescribing opiate agonists and sildenafil concomitantly.
    Simeprevir: (Moderate) Simeprevir, a mild intestinal CYP3A4 inhibitor, may increase the side effects of oxycodone, which is a CYP3A4 substrate. Monitor patients for adverse effects of oxycodone, such as CNS and respiratory depression.
    Skeletal Muscle Relaxants: (Major) Concomitant use of opiate agonists with skeletal muscle relaxants may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with skeletal muscle relaxants 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 oxycodone or oxycodone; naloxone is initiated in a patient taking a skeletal muscle relaxant, use an initial dose of oxycodone at one-third to one-half the usual dosage and titrate to clinical response; reduced initial doses of oxycodone; naltrexone, aspirin, ASA; oxycodone, and ibuprofen; oxycodone are also recommended. If a decision is made to start treatment with acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours. If a skeletal muscle relaxant is prescribed for a patient taking an opiate agonist, use a lower initial dose of the skeletal muscle relaxant and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
    Sodium Bicarbonate: (Minor) Antacids can delay the oral absorption of acetaminophen, but the interactions are not likely to be clinically significant as the extent of acetaminophen absorption is not appreciably affected.
    Sodium Oxybate: (Major) Additive CNS depressant effects may be possible when sodium oxybate is used concurrently with opiate agonists.
    Solifenacin: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when oxycodone is used concomitantly with an anticholinergic drug, such as solifenacin. The concomitant use of oxycodone and anticholinergic drugs 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.
    Spironolactone: (Moderate) Opiate agonists like oxycodone may potentiate orthostatic hypotension when given concomitantly with spironolactone.
    St. John's Wort, Hypericum perforatum: (Minor) St. John's wort, Hypericum perforatum induces cytochrome P450 1A2. About 10 to 15% of the acetaminophen dose undergoes oxidative metabolism via cytochrome P450 isoenzymes CYP2E1, 3A4 and 1A2, which produces the hepatotoxic metabolite, N-acetyl-p-benzoquinonimine. Thus, theoretically St. John's wort might increase the risk of acetaminophen-induced hepatotoxicity by increasing the metabolism of acetaminophen to NAPQI.
    Streptogramins: (Moderate) Concomitant use of oxycodone with dalfopristin; quinupristin may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of dalfopristin; quinupristin could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If dalfopristin; quinupristin is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and dalfopristin; quinupristin is a strong CYP3A4 inhibitor.
    Succinylcholine: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as neuromuscular blockers, can potentiate the effects of alfentanil on respiration, alertness, and blood pressure. A dose reduction of one or both drugs may be warranted.
    Sulfinpyrazone: (Minor) Sulfinpyrazone can induce hepatic oxidative microsomal enzymes and the drug has been shown to increase acetaminophen clearance by roughly 23%. Theoretically, it is thought that the induction of acetaminophen metabolism by sulfinpyrazone may increase the risk of acetaminophen hepatotoxicity due to the formation of increased amounts of toxic acetaminophen metabolites, but there is no confirmatory evidence.
    Sumatriptan: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as serotonin-receptor agonists. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea.
    Suvorexant: (Moderate) CNS depressant drugs may have cumulative effects when administered concurrently and they should be used cautiously with suvorexant. A reduction in dose of the CNS depressant may be needed in some cases.
    Tapentadol: (Major) Additive CNS depressive effects are expected if tapentadol is used in conjunction with other CNS depressants, including other opiate agonists. Severe hypotension, profound sedation, coma, or respiratory depression may occur. Prior to concurrent use of tapentadol 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 an opiate agonist is used concurrently with tapentadol, a reduced dosage of tapentadol and/or the opiate agonist is recommended. If the extended-release tapentadol tablets are used concurrently with a CNS depressant, it is recommended to use an initial tapentadol dose of 50 mg PO every 12 hours. Monitor patients for sedation and respiratory depression.
    Telaprevir: (Moderate) Close clinical monitoring is advised when administering acetaminophen with telaprevir due to an increased potential for acetaminophen-related adverse events. If acetaminophen dose adjustments are made, re-adjust the dose upon completion of telaprevir treatment. Although this interaction has not been studied, predictions about the interaction can be made based on the metabolic pathway of acetaminophen. Acetaminophen is partially metabolized by the hepatic isoenzyme CYP3A4; telaprevir inhibits this isoenzyme. Coadministration may result in elevated acetaminophen plasma concentrations. (Moderate) Close clinical monitoring is advised when administering oxycodone with telaprevir due to an increased potential for oxycodone-related adverse events. If oxycodone dose adjustments are made, re-adjust the dose upon completion of telaprevir treatment. Although this interaction has not been studied, predictions about the interaction can be made based on the metabolic pathway of oxycodone. Oxycodone is partially metabolized by the hepatic isoenzyme CYP3A4; telaprevir inhibits this isoenzyme. Coadministration may result in elevated oxycodone plasma concentrations.
    Telithromycin: (Major) Coadministration of telithromycin and oxycodone may result in increased oxycodone plasma concentrations and a higher risk for adverse or prolonged effects, such as potentially fatal respiratory depression. Oxycodone is metabolized by CYP3A4; telithromycin is a CYP3A4 inhibitor. If coadministration of these agents is necessary, patients should be monitored for an extended period of time and dosage adjustments made if warranted.
    Telotristat Ethyl: (Moderate) Use caution if coadministration of telotristat ethyl and oxycodone is necessary, as the systemic exposure of oxycodone may be decreased resulting in reduced efficacy and may lead to opioid withdrawal symptoms in patients physically dependent on oxycodone. If these drugs are used together, monitor patients for suboptimal efficacy of oxycodone or for signs or symptoms of opioid withdrawal; consider increasing the dose of oxycodone if necessary. If telotristat ethyl is discontinued, oxycodone exposure may increase; monitor patients for respiratory depression and sedation and consider a oxycodone dose reduction. Oxycodone is a CYP3A4 substrate. The mean Cmax and AUC of another sensitive CYP3A4 substrate was decreased by 25% and 48%, respectively, when coadministered with telotristat ethyl; the mechanism of this interaction appears to be that telotristat ethyl increases the glucuronidation of the CYP3A4 substrate. (Moderate) Use telotristat ethyl and CYP3A4 substrates, such as acetaminophen, together with caution; the systemic exposure of acetaminophen may be decreased resulting in reduced efficacy. If these drugs are used together, monitor patients for suboptimal efficacy of acetaminophen; consider increasing the dose of acetaminophen if necessary. The systemic exposure of a sensitive CYP3A4 substrate was significantly decreased (by 48%) when it was coadministered with telotristat ethyl. The mechanism of this drug interaction appears to be that telotristat ethyl increases the glucuronidation of the CYP3A4 substrate.
    Temazepam: (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 oxycodone is initiated in a patient taking a benzodiazepine, reduce dosages and titrate to clinical response. For acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours, and for other oxycodone products, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. 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.
    Terbinafine: (Moderate) Oxycodone is metabolized in part by cytochrome P450 2D6 to oxymorphone, which represents < 15% of the total administered dose. Potent inhibitors of CYP2D6, such as terbinafine, may potentially increase the effects of oxycodone; however, such blockade has not been shown to be of clinical significance during oxycodone treatment. Clinicians should be aware of this possible interaction.
    Tetrabenazine: (Moderate) Additive effects are possible when tetrabenazine is combined with other drugs that cause CNS depression. Concurrent use of tetrabenazine and drugs that can cause CNS depression, such as opiate agonists, can increase both the frequency and the intensity of adverse effects such as drowsiness, sedation, dizziness, and orthostatic hypotension.
    Tetracaine: (Major) Due to the central nervous system depression potential of local anesthetics, they should be used with caution with other agents that can cause respiratory depression, such as opiate agonists. Excitation or depression of the CNS may be the first manifestation of CNS toxicity. Restlessness, anxiety, tinnitus, dizziness, blurred vision, tremors, depression, or drowsiness may be early warning signs of CNS toxicity. After each local anesthetic injection, careful and constant monitoring of ventilation adequacy, cardiovascular vital signs, and the patient's state of consciousness is advised.
    Thalidomide: (Major) Avoid the concomitant use of thalidomide with opiate agonists; antihistamines; antipsychotics; anxiolytics, sedatives, and hypnotics; and other central nervous system depressants due to the potential for additive sedative effects.
    Thiazide diuretics: (Moderate) Opiate agonists may potentiate orthostatic hypotension when used concurrently with thiazide diuretics.
    Thiethylperazine: (Moderate) Concomitant use of oxycodone with phenothiazines may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Prior to 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. Furthermore, oxycodone is metabolized in part by 2D6 to oxymorphone, which represents < 15% of the total administered dose. Concurrent use of some agents that inhibit CYP2D6 (e.g., quinidine) has not been shown to result in clinically significant interactions. However, many phenothiazines are inhibitors of CYP2D6 (e.g., chlorpromazine, perphenazine, thioridazine) and may potentially increase the effects of oxycodone. Also, severe hypotension may be potentiated with concurrent phenothiazine usage or other drug that compromises vasomotor tone.
    Thiopental: (Minor) Chronic therapy with barbiturates can increase the metabolism and decrease the effectiveness of acetaminophen. During acute overdoses, barbiturates can enhance the formation of toxic acetaminophen metabolites.
    Thioridazine: (Moderate) Concomitant use of oxycodone with phenothiazines may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Prior to 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. Furthermore, oxycodone is metabolized in part by 2D6 to oxymorphone, which represents < 15% of the total administered dose. Concurrent use of some agents that inhibit CYP2D6 (e.g., quinidine) has not been shown to result in clinically significant interactions. However, many phenothiazines are inhibitors of CYP2D6 (e.g., chlorpromazine, perphenazine, thioridazine) and may potentially increase the effects of oxycodone. Also, severe hypotension may be potentiated with concurrent phenothiazine usage or other drug that compromises vasomotor tone.
    Thiothixene: (Moderate) Thiothixene can potentiate the CNS-depressant action of other drugs such as opiate agonists. Caution should be exercised during simultaneous use of these agents due to potential excessive CNS effects or additive hypotension.
    Tipranavir: (Moderate) Concomitant use of oxycodone with tipranavir may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of tipranavir could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If tipranavir is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and tipranavir is a CYP3A4 inhibitor.
    Tizanidine: (Major) Concomitant use of opiate agonists with skeletal muscle relaxants may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with skeletal muscle relaxants 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 oxycodone or oxycodone; naloxone is initiated in a patient taking a skeletal muscle relaxant, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage and titrate to clinical response; reduced initial doses of oxycodone; naltrexone, aspirin, ASA; oxycodone, and ibuprofen; oxycodone are also recommended. If a decision is made to start treatment with acetaminophen; oxycodone extended-release tabIets, start with 1 tablet PO every 12 hours. If a skeletal muscle relaxant is prescribed for a patient taking an opiate agonist, use a lower initial dose of the skeletal muscle relaxant and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. (Minor) Tizanidine delays the time to attain peak concentrations of acetaminophen by about 16 minutes. The clinical significance of this interaction is unknown.
    Tobacco: (Moderate) Tobacco smoking induces the cytochrome P450 isoenzyme CYP1A2 and may potentially increase the risk for acetaminophen-induced hepatotoxicity during overdose via enhanced generation of acetaminophen's hepatotoxic metabolite, NAPQI. In one study, current tobacco smoking was found to be very frequent in patients admitted with acetaminophen poisoning. Tobacco smoking appears to be an independent risk factor of severe hepatotoxicity, acute liver failure and death following acetaminophen overdose.
    Tolcapone: (Moderate) Concomitant use of opiate agonists with other central nervous system (CNS) depressants such as COMT inhibitors can potentiate the effects of the opiate and may lead to additive CNS or respiratory depression, profound sedation, or coma. Prior to concurrent use of an opiate 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 the opiate 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.
    Tolterodine: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when oxycodone is used concomitantly with an anticholinergic drug, such as tolterodine. The concomitant use of oxycodone and anticholinergic drugs 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.
    Tramadol: (Major) Concomitant use of tramadol increases the seizure risk in patients taking opiate agonists. Also, tramadol can cause additive CNS depression and respiratory depression when used with opiate agonists; avoid concurrent use whenever possible. If used together, extreme caution is needed, and a reduced tramadol dose is recommended.
    Trandolapril; Verapamil: (Moderate) Concomitant use of oxycodone with verapamil may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of verapamil could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If verapamil is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and verapamil is a CYP3A4 inhibitor.
    Trazodone: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as trazodone, can lead to additive respiratory depression, hypotension, profound sedation, or coma. 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. Oxycodone should be used in reduced dosages if used concurrently with a CNS depressant; initiate oxycodone 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. Monitor patients for sedation and respiratory depression.
    Triazolam: (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 oxycodone is initiated in a patient taking a benzodiazepine, reduce dosages and titrate to clinical response. For acetaminophen; oxycodone extended-release tablets, start with 1 tablet PO every 12 hours, and for other oxycodone products, use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. 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.
    Tricyclic antidepressants: (Moderate) Concomitant use of oxycodone and tricyclic antidepressants (TCAs) may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Orthostasis may occur in ambulatory patients. Constipation occurs with both oxycodone and TCA use. Prior to concurrent use of oxycodone in patients taking a TCA, 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 TCA is used concurrently with oxycodone, a reduced dosage of oxycodone is recommended; use an initial dose of oxycodone at one-third to one-half the usual dosage. Monitor for sedation and respiratory depression and for reduced GI motility. Caution should also be observed when administering TCAs with opiates having serotonergic properties such as oxycodone. Serotonin syndrome may rarely occur and is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma). If serotonin syndrome is suspected, both the TCA and concurrent serotonergic agents should be discontinued.
    Trifluoperazine: (Moderate) Concomitant use of oxycodone with phenothiazines may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Prior to 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. Furthermore, oxycodone is metabolized in part by 2D6 to oxymorphone, which represents < 15% of the total administered dose. Concurrent use of some agents that inhibit CYP2D6 (e.g., quinidine) has not been shown to result in clinically significant interactions. However, many phenothiazines are inhibitors of CYP2D6 (e.g., chlorpromazine, perphenazine, thioridazine) and may potentially increase the effects of oxycodone. Also, severe hypotension may be potentiated with concurrent phenothiazine usage or other drug that compromises vasomotor tone.
    Trimethobenzamide: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like opiate agonists, may potentiate the effects of either trimethobenzamide or the opiate agonist.
    Trimetrexate: (Moderate) Acetaminophen can inhibit oxidative hepatic enzymes responsible for metabolizing trimetrexate. Concurrent use can decrease the clearance of trimetrexate and thus increase its plasma levels.
    Trimipramine: (Moderate) Concomitant use of oxycodone and tricyclic antidepressants (TCAs) may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Orthostasis may occur in ambulatory patients. Constipation occurs with both oxycodone and TCA use. Prior to concurrent use of oxycodone in patients taking a TCA, 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 TCA is used concurrently with oxycodone, a reduced dosage of oxycodone is recommended; use an initial dose of oxycodone at one-third to one-half the usual dosage. Monitor for sedation and respiratory depression and for reduced GI motility. Caution should also be observed when administering TCAs with opiates having serotonergic properties such as oxycodone. Serotonin syndrome may rarely occur and is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma). If serotonin syndrome is suspected, both the TCA and concurrent serotonergic agents should be discontinued.
    Triprolidine: (Moderate) Concomitant use of oxycodone with sedating H1-blockers 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.
    Trospium: (Moderate) Monitor patients for signs of urinary retention or reduced gastric motility when opiate agonists are used concomitantly with an anticholinergic drug, such as trospium. The concomitant use of opiate agonists and anticholinergic drugs 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.
    Tubocurarine: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as neuromuscular blockers, can potentiate the effects of alfentanil on respiration, alertness, and blood pressure. A dose reduction of one or both drugs may be warranted.
    Valerian, Valeriana officinalis: (Moderate) Any substances that act on the CNS may theoretically interact with valerian, Valeriana officinalis. The valerian derivative, dihydrovaltrate, binds at barbiturate binding sites; valerenic acid has been shown to inhibit enzyme-induced breakdown of GABA in the brain; the non-volatile monoterpenes (valepotriates) have sedative activity. The sedative effect may be additive to other drugs with sedative actions, such as the opiate agonists. Consider the patient's use of alcohol or illicit drugs. If valerian is used concurrently with a CNS depressant, a reduced dosage of the CNS depressant may be required, or, the valerian supplement may be discontinued. Carefully monitor the patient for hypotension, CNS depression, and respiratory depression.
    Vecuronium: (Moderate) Concomitant use of oxycodone with other CNS depressants, such as neuromuscular blockers, can potentiate the effects of alfentanil on respiration, alertness, and blood pressure. A dose reduction of one or both drugs may be warranted.
    Vemurafenib: (Moderate) Concomitant use of vemurafenib and acetaminophen may result in altered concentrations of acetaminophen. Vemurafenib is an inhibitor of CYP1A2 and CYP2A6, and an inducer of CYP3A4. Acetaminophen is a substrate of CYP1A2, CYP2A6, and CYP3A4. Use caution and monitor patients for toxicity and efficacy. (Moderate) Concomitant use of vemurafenib and oxycodone may result in altered concentrations of oxycodone. Vemurafenib is a weak inhibitor of CYP2D6 and an inducer of CYP3A4. Oxycodone is a substrate of CYP2D6 and CYP3A4. Use caution and monitor patients for toxicity and efficacy.
    Verapamil: (Moderate) Concomitant use of oxycodone with verapamil may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of verapamil could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If verapamil is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and verapamil is a CYP3A4 inhibitor.
    Vigabatrin: (Moderate) Vigabatrin may cause somnolence and fatigue. Drugs that can cause CNS depression, if used concomitantly with vigabatrin, may increase both the frequency and the intensity of adverse effects such as drowsiness, sedation, and dizziness. Caution should be used when vigabatrin is given with opiate agonists.
    Vilazodone: (Moderate) Due to the CNS effects of vilazodone, caution should be used when vilazodone is given in combination with other centrally acting medications such as opiate agonists.
    Voriconazole: (Major) Oxycodone is metabolized by CYP3A4. Concomitant administration of a CYP3A4 inhibitor, such as voriconazole, may cause an increase in oxycodone plasma concentrations, which could increase or prolong adverse effects and may cause potentially fatal respiratory depression. Coadministration of voriconazole and oxycodone increased oxycodone AUC by 3.6-fold and the Cmax by 1.7-fold. If coadministration of these agents is necessary, patients should be monitored for an extended period of time and dosage adjustments made if warranted.
    Warfarin: (Minor) Although acetaminophen is routinely considered safer than aspirin and agent of choice when a mild analgesic/antipyretic is necessary for a patient receiving therapy with warfarin, acetaminophen has also been shown to augment the hypoprothrombinemic response to warfarin. Concomitant acetaminophen ingestion may result in increases in the INR in a dose-related fashion. Clinical bleeding has been reported. Single doses or short (i.e., several days) courses of treatment with acetaminophen are probably safe in most patients taking warfarin. Clinicians should be alert for an increased INR if acetaminophen is administered in large daily doses for longer than 10 to 14 days.
    Zafirlukast: (Moderate) Concomitant use of oxycodone with zafirlukast may increase oxycodone 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 oxycodone until stable drug effects are achieved. Discontinuation of zafirlukast could decrease oxycodone plasma concentrations, decrease opioid efficacy, and potentially lead to a withdrawal syndrome in those with physical dependence to oxycodone. If zafirlukast is discontinued, monitor the patient carefully and consider increasing the opioid dosage if appropriate. Oxycodone is a substrate for CYP3A4 and zafirlukast is a CYP3A4 inhibitor.
    Zaleplon: (Moderate) Concomitant use of oxycodone with zaleplon may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. 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. If zaleplon is used concurrently with oxycodone, a reduced dosage of oxycodone and/or zaleplon is recommended; use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. Monitor for sedation and respiratory depression.
    Ziconotide: (Moderate) Concurrent use of ziconotide and opiate agonists may result in an increased incidence of dizziness and confusion. Ziconotide neither interacts with opiate receptors nor potentiates opiate-induced respiratory depression. However, in animal models, ziconotide did potentiate gastrointestinal motility reduction by opioid agonists.
    Zidovudine, ZDV: (Minor) Both acetaminophen and zidovudine, ZDV undergo glucuronidation. Competition for the metabolic pathway is thought to have caused a case of acetaminophen-related hepatotoxicity. This interaction may be more clinically significant in patients with depleted glutathione stores, such as patients with acquired immunodeficiency syndrome, poor nutrition, or alcoholism.
    Ziprasidone: (Moderate) Ziprasidone has the potential to impair cognitive and motor skills. Additive CNS depressant effects are possible when ziprasidone is used concurrently with any CNS depressant, including oxycodone.
    Zolmitriptan: (Major) Serotonin syndrome can occur during concomitant use of opiate agonists with serotonergic drugs, such as serotonin-receptor agonists. Symptoms may occur hours to days after concomitant use, particularly after dose increases. Serotonin syndrome may occur within recommended dose ranges. If concomitant treatment is clinically warranted, careful observation of the patient is advised, especially during initiation of the second therapy and after dosage increases of either agent. Instruct patients to immediately report symptoms of agitation, hallucinations, tachycardia, fever, excessive sweating, shivering or shaking, muscle twitching or stiffness, trouble with coordination, nausea, vomiting, or diarrhea. (Minor) Zolmitriptan can delay the Tmax of acetaminophen by one hour. A single 1 g dose of acetaminophen does not alter the pharmacokinetics of zolmitriptan and its active metabolite. The interaction between zolmitriptan and acetaminophen is not likely to be clinically significant.
    Zolpidem: (Moderate) Concomitant use of oxycodone with zolpidem may lead to additive respiratory and/or CNS depression. Hypotension, profound sedation, coma, respiratory depression, or death may occur. In addition, sleep-related behaviors, such as sleep-driving, are more likely to occur during concurrent use of zolpidem and other CNS depressants than with zolpidem alone. 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. If zolpidem is used concurrently with oxycodone, a reduced dosage of oxycodone and/or zolpidem is recommended; use an initial dose of oxycodone at 1/3 to 1/2 the usual dosage. For Intermezzo brand of sublingual zolpidem tablets, reduce the dose to 1.75 mg/night. Monitor for sedation and respiratory depression.

    PREGNANCY AND LACTATION

    Pregnancy

    Acetaminophen; oxycodone is classified as FDA pregnancy risk category C. No well-controlled studies in pregnant women have been performed. Some experts suggest increased risk of oxycodone if used for prolonged periods or at high doses near term. Chronic maternal use of opioids during pregnancy may result in neonatal opioid withdrawal syndrome. This syndrome can be life-threatening and includes symptoms such as poor feeding, irritability, hyperactivity and abnormal sleep pattern, high pitched cry, tremor, vomiting, diarrhea, rigidity, and seizures. Neonates whose mothers have been taking oxycodone chronically may show some respiratory depression and/or withdrawal symptoms at birth or within a few days. Neonatal opioid withdrawal syndrome may be life-threatening and should be treated according to protocols developed by neonatology experts. Acetaminophen; oxycodone should not be used immediately prior to or during labor or obstetric delivery due to the potential for respiratory depression in the newborn. No overall increase in fetal mortality, as determined by pregnancy outcomes of mothers that overdosed on various amounts of acetaminophen, was apparent amongst 300 women. Treatment with acetylcysteine or methionine did not appear to affect fetal or neonatal toxicity. Of 235 babies exposed to an overdose of only acetaminophen, 168 were normal, 8 had malformations, 16 were spontaneously aborted, and 43 were electively terminated. Of 67 babies exposed to an overdose of a combination acetaminophen product, 51 were normal, 3 had malformations, 2 were spontaneously aborted (late fetal deaths), and 11 were electively terminated. None of the babies with malformations were exposed during the first trimester, but all of the spontaneous abortions and one of the late fetal deaths were subsequent to first trimester exposure.

    MECHANISM OF ACTION

    Mechanism of Action: Acetaminophen-oxycodone combination produces analgesia through two different mechanisms leading to a synergistic analgesic effect.•Oxycodone: Oxycodone is a potent µ-opiate receptor agonist. Opioid analgesia is mediated through changes in the perception of pain at the spinal cord and higher levels in the CNS. Opioids 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.•Acetaminophen: Acetaminophen acts primarily in the CNS and increases the pain threshold by inhibiting cyclooxygenase, an enzyme involved in prostaglandin (PG) synthesis. Acetaminophen inhibits both isoforms of cyclooxygenase, COX-1 and COX-2, but does so centrally; acetaminophen does not inhibit PG synthesis in peripheral tissues, which is the reason for its lack of peripheral anti-inflammatory effects. The antipyretic activity of acetaminophen is exerted by blocking the effects of endogenous pyrogen on the hypothalamic heat-regulating center via inhibition of PG synthesis.

    PHARMACOKINETICS

    Acetaminophen; oxycodone is administered orally. Both acetaminophen and oxycodone are metabolized in the liver via cytochrome P450 (CYP) isoenzymes and excreted through the kidney. Administration of other drugs which affect these isoenzymes may affect the efficacy and incidence of adverse reactions from the acetaminophen-oxycodone combination.
    Oxycodone: The metabolism of oxycodone is mediated through CYP2D6.
    Acetaminophen: Acetaminophen primarily undergoes glucuronidation and sulfate conjugation; however, a small percentage of the dose is metabolized via CYP2E1 and CYP1A2 to a hepatotoxic metabolite. The elimination half-life of this compound is approximately 4 hours. Depletion of glucuronide and sulfate stores due to chronic ethanol use or acute acetaminophen overdose may increase oxidative metabolism of acetaminophen leading to hepatotoxicity.

    Oral Route

    For immediate-release formulations, the onset of analgesia is within 30 minutes with peak analgesic effects in about 90 minutes. The duration of analgesia is 3—4 hours. After administration of the extended-release tablets, maximum plasma concentrations of acetaminophen and oxycodone occur in approximately 1 and 3 hours, respectively. Steady state concentrations are achieved within 24 hours of initiation.