Limbitrol DS

Anxiolytics, Non-Benzodiazepines
Psycholeptic-psychoanaleptic Combinations

Oral Administration

May administer chlordiazepoxide; amitriptyline without regard to meals.

Severe

suicidal ideation / Delayed / Incidence not known
seizures / Delayed / Incidence not known
cardiomyopathy / Delayed / Incidence not known
stroke / Early / Incidence not known
arrhythmia exacerbation / Early / Incidence not known
myocardial infarction / Delayed / Incidence not known
AV block / Early / Incidence not known
ileus / Delayed / Incidence not known
ocular hypertension / Delayed / Incidence not known
SIADH / Delayed / Incidence not known
anaphylactoid reactions / Rapid / Incidence not known
porphyria / Delayed / Incidence not known
angioedema / Rapid / Incidence not known
agranulocytosis / Delayed / Incidence not known
serotonin syndrome / Delayed / Incidence not known
neonatal respiratory depression / Rapid / Incidence not known
neonatal abstinence syndrome / Early / Incidence not known

Moderate

constipation / Delayed / 1.0-10.0
impaired cognition / Early / Incidence not known
confusion / Early / Incidence not known
hallucinations / Early / Incidence not known
mania / Early / Incidence not known
euphoria / Early / Incidence not known
depression / Delayed / Incidence not known
amnesia / Delayed / Incidence not known
memory impairment / Delayed / Incidence not known
ataxia / Delayed / Incidence not known
pseudoparkinsonism / Delayed / Incidence not known
EEG changes / Delayed / Incidence not known
orthostatic hypotension / Delayed / Incidence not known
hypotension / Rapid / Incidence not known
hypertension / Early / Incidence not known
QT prolongation / Rapid / Incidence not known
palpitations / Early / Incidence not known
sinus tachycardia / Rapid / Incidence not known
elevated hepatic enzymes / Delayed / Incidence not known
jaundice / Delayed / Incidence not known
blurred vision / Early / Incidence not known
ejaculation dysfunction / Delayed / Incidence not known
urinary incontinence / Early / Incidence not known
impotence (erectile dysfunction) / Delayed / Incidence not known
hyponatremia / Delayed / Incidence not known
urinary retention / Early / Incidence not known
galactorrhea / Delayed / Incidence not known
testicular swelling / Early / Incidence not known
edema / Delayed / Incidence not known
parotitis / Delayed / Incidence not known
thrombocytopenia / Delayed / Incidence not known
eosinophilia / Delayed / Incidence not known
tolerance / Delayed / Incidence not known
withdrawal / Early / Incidence not known
psychological dependence / Delayed / Incidence not known
physiological dependence / Delayed / Incidence not known

Mild

dizziness / Early / 10.0
drowsiness / Early / 10.0
xerostomia / Early / 10.0
lethargy / Early / Incidence not known
restlessness / Early / Incidence not known
abnormal dreams / Early / Incidence not known
fatigue / Early / Incidence not known
weakness / Early / Incidence not known
tremor / Early / Incidence not known
syncope / Early / Incidence not known
paresthesias / Delayed / Incidence not known
dyspepsia / Early / Incidence not known
tongue discoloration / Delayed / Incidence not known
nausea / Early / Incidence not known
vomiting / Early / Incidence not known
anorexia / Delayed / Incidence not known
diarrhea / Early / Incidence not known
dysgeusia / Early / Incidence not known
weight gain / Delayed / Incidence not known
mydriasis / Early / Incidence not known
gynecomastia / Delayed / Incidence not known
libido increase / Delayed / Incidence not known
menstrual irregularity / Delayed / Incidence not known
libido decrease / Delayed / Incidence not known
breast enlargement / Delayed / Incidence not known
increased urinary frequency / Early / Incidence not known
photosensitivity / Delayed / Incidence not known
urticaria / Rapid / Incidence not known
pruritus / Rapid / Incidence not known
rash / Early / Incidence not known
headache / Early / Incidence not known
hyperhidrosis / Delayed / Incidence not known
alopecia / Delayed / Incidence not known
purpura / Delayed / Incidence not known

Children, suicidal ideation

Patients who present for chlordiazepoxide; amitriptyline treatment should be thoroughly evaluated prior to initiation of the drug; suicidal tendencies may be present and protective measures may be necessary (e.g., limiting the total prescription size and increased monitoring). The safe and effective use of chlordiazepoxide; amitriptyline has not been established in pediatric patients less than 18 years of age. In a pooled analysis of placebo-controlled trials of antidepressants (n = 4,500 pediatrics and 77,000 adults), there was an increased risk for suicidal thoughts and behaviors in children, adolescent, and young adult patients 24 years of age and younger receiving an antidepressant versus placebo, with considerable variation in the risk of suicidality among drugs. The difference in absolute risk of suicidal thoughts and behaviors across different indications was highest in those with major depression. The need for an antidepressant in children, adolescents, or young adults for any use must be weighed against the risk of suicidality; it is unknown if this risk extends to long-term use. Monitor for symptom worsening or suicidality, especially at treatment initiation or after dose changes. Caregivers and/or patients should immediately notify the prescriber of changes in behavior or suicidal ideation. A change to the treatment regimen may be necessary in patients with emerging suicidality or worsening depression. The possibility of suicide in depressed patients remains until significant remission occurs. Children are generally more sensitive to the CNS effects of the benzodiazepines, and tricyclic antidepressants (TCAs) should be used with caution in children with a known family history of heart disease or taking medications that may prolong the QT interval. Routine cardiovascular monitoring has been suggested for children receiving TCAs due to the potential of these agents to produce adverse cardiac effects.

Chronic obstructive pulmonary disease (COPD), CNS depression, coadministration with other CNS depressants, pulmonary disease, respiratory insufficiency, sleep apnea

Serious adverse reactions to chlordiazepoxide; amitriptyline include CNS depression and respiratory depression. Chlordiazepoxide coadministration with other CNS depressants, especially opioids, should be avoided unless no other alternatives are available as coadministration significantly increases the risk for profound sedation, respiratory depression, coma, and death. Observational studies have demonstrated that concomitant use of opioid analgesics and benzodiazepines increases the risk of drug-related mortality compared to the use of opioids alone. Reserve concomitant prescribing of these drugs for when alternative treatment options are inadequate. Limit dosages and durations to the minimum required and follow patients for signs and symptoms of respiratory depression and sedation. As with other benzodiazepines, chlordiazepoxide use should be avoided in patients with significant pulmonary disease if possible; if use of the drug is necessary, close monitoring of pulmonary function is recommended. Chlordiazepoxide; amitriptyline should be avoided if possible in patients with pre-existing respiratory insufficiency, such as severe chronic obstructive pulmonary disease (COPD) or sleep apnea because the drug can exacerbate respiratory depression.

Abrupt discontinuation, alcoholism, benzodiazepine dependence, substance abuse

Use chlordiazepoxide; amitriptyline with caution in patients with a history of alcoholism or substance abuse due to the potential for psychological dependence. The use of benzodiazepines exposes users to risks of abuse, misuse, and addiction, which can lead to overdose or death. Assess patients for risks of addiction, abuse, or misuse before drug initiation, and monitor patients who receive benzodiazepines routinely for development of these behaviors or conditions. A potential risk of abuse should not preclude appropriate treatment in any patient, but requires more intensive counseling and monitoring. To discourage abuse, the smallest appropriate quantity of the benzodiazepine should be prescribed, and proper disposal instructions for unused drug should be given to patients. Avoid or minimize concomitant use of CNS depressants or other medications associated with addiction or abuse. Abuse and misuse of benzodiazepines commonly involve concomitant use of other medications, alcohol, and/or illicit substances, which is associated with an increased frequency of serious adverse outcomes, including respiratory depression, overdose, and death. Advise patients to seek immediate medical attention if they experience symptoms such as trouble breathing. Abrupt discontinuation of chlordiazepoxide; amitriptyline should be avoided because it could precipitate symptoms of cholinergic rebound due to the TCA component (such as nausea, vomiting, or diarrhea) or benzodiazepine withdrawal symptoms. The risks of physiological dependence on benzodiazepines and withdrawal increase with longer treatment duration and higher daily dose. Benzodiazepine dependence can occur after administration of therapeutic doses for as few as 1 to 2 weeks and withdrawal symptoms may be seen after the discontinuation of therapy. To reduce the risk of acute withdrawal reactions, use a gradual taper to reduce the dosage or to discontinue benzodiazepines. No standard benzodiazepine tapering schedule is suitable for all patients; therefore, create a patient-specific plan to gradually reduce the dosage. If a patient develops withdrawal reactions, consider pausing the taper or increasing the dosage to the previous tapered dosage level. Subsequently, decrease the dosage more slowly. Patients with a history of seizure should not be withdrawn abruptly from benzodiazepines due to the risk of precipitating seizure; status epilepticus has also been reported. Clinicians should be aware that the use of flumazenil may increase the risk of seizure, particularly in long-term users of benzodiazepines and in cyclic antidepressant overdoses.

Limbitrol, Limbitrol DS

Rx, schedule IV

Oral antidepressant/anti-anxiety combination product.
Amitriptyline is a tricyclic antidepressant (TCA), chlordiazepoxide is a benzodiazepine.
Common ADRs include anticholinergic effects and drowsiness.

For the treatment of moderate to severe depression with concurrent symptoms of moderate to severe anxiety in adult patients. Oral dosage Adults

Initially, 1 regular strength tablet (containing chlordiazepoxide 5 mg with amitriptyline 12.5 mg) or 1 double strength (DS) tablet (containing chlordiazepoxide 10 mg with amitriptyline 25 mg) PO 3 to 4 times per day. Adjust dose as tolerated and required; some patients may respond to doses as low as 2 tablets/day PO and the total daily dose administered at bedtime. The larger portion of the total daily dose may be taken at bedtime. In some patients, a single dose at bedtime may be adequate. Maximum: 60 mg chlordiazepoxide with 150 mg of amitriptyline per day (e.g., up to 6 DS tablets/day). Generally, acute episodes of depression require several months of sustained treatment. Once an adequate response is attained, use the smallest effective dose that maintains remission. Symptoms likely to respond in the first week of treatment include: insomnia, feelings of guilt or worthlessness, agitation, psychic and somatic anxiety, suicidal ideation, and anorexia.

Geriatric Adults

Initially, 1 regular strength tablet (containing chlordiazepoxide 5 mg with amitriptyline 12.5 mg) or 1 double strength (DS) tablet (containing chlordiazepoxide 10 mg with amitriptyline 25 mg) PO 3 to 4 times per day. Use the lowest effective dose. Adjust dose as tolerated and required; some patients may respond to doses as low as 2 tablets/day PO, with the dose given at bedtime. The larger portion of the total daily dose may be taken at bedtime. Max: 60 mg chlordiazepoxide with 150 mg of amitriptyline per day (e.g., up to 6 DS tablets/day). The federal Omnibus Budget Reconciliation Act (OBRA) regulates medication use in long-term care facility (LTCF) residents. Tricyclic antidepressants are not drugs of choice due to strong anticholinergic and sedative properties. Use of long-acting benzodiazepines such as chlordiazepoxide may also expose the resident to unnecessary risks. OBRA daily dose thresholds are not available for combination of amitriptyline; chlordiazepoxide; the daily dose of chlordiazepoxide should not exceed 20 mg/day, except when documentation is provided showing that higher doses are necessary to maintain or improve the resident's functional status. In addition, the facility should attempt periodic tapering of antidepressants and anxiolytics or provide documentation of medical necessity in accordance with OBRA guidelines.

Hepatic Impairment

Specific guidelines for dosage adjustments in hepatic impairment are not available. Chlordiazepoxide; amitriptyline should be used with caution in those with hepatic impairment. With repeat dosing, the risk of accumulation of either drug component is high. Patients with hepatic disease should receive reduced initial dosages and slow dose titration and should be closely monitored for tolerability. For example, chlordiazepoxide metabolites may accumulate leading to severe and prolonged stupor in patients with cirrhosis or hepatitis.

Renal Impairment

Specific dose recommendations for chlordiazepoxide; amitriptyline in patients with renal impairment are not available. Care should be exercised in dosage selection, usually starting at the low end of the dosage range and titrating up based on clinical response. When amitriptyline is used as a single agent, little unchanged drug appears in the urine. However, when chlordiazepoxide is used as a single agent, a 50% dose reduction is required in patients with renal failure (CrCl less than 10 mL/minute). Because chlordiazepoxide; amitriptyline exists as a fixed dose combination product, a reduction in the chlordiazepoxide dose alone is not possible. Because the risk of toxic reactions is higher in patients with renal dysfunction, it may be useful to monitor renal function, especially in the elderly.
 
Intermittent hemodialysis:
Hemodialysis is reported as ineffective in removing amitriptyline from the body.

Abarelix: (Major) Abarelix carries an established risk for QT prolongation. In a single, active-controlled, clinical study comparing abarelix to LHRH agonist plus nonsteroidal antiandrogen, periodic ECGs were performed. Both therapies prolonged the mean QTc interval by >10 msec from baseline. Patients with a baseline QTc value greater than 450 milliseconds may not be appropriate candidates for abarelix receipt. Prescribers need to weigh the potential benefits and risks of abarelix use in patients with prolonged QT syndrome or in patients taking other drugs that may prolong the QT interval, including tricyclic antidepressants (TCAs). Tricyclic antidepressants (TCAs) share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). ECG monitoring is recommended if the drugs must be used together.
Abiraterone: (Moderate) Monitor for an increase in amitriptyline-related adverse reactions if coadministration with abiraterone is necessary; a dose reduction of amitriptyline may be necessary. Amitriptyline is a CYP2D6 substrate and abiraterone is a moderate CYP2D6 inhibitor. Patients who are stable on a given dose of amitriptyline may become abruptly toxic when given abiraterone is concomitant therapy.
Acetaminophen; Aspirin, ASA; Caffeine: (Minor) Patients taking benzodiazepines for insomnia should not use caffeine-containing products prior to going to bed as these products may antagonize the sedative effects of the benzodiazepine.
Acetaminophen; Aspirin; Diphenhydramine: (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of diphenhydramine and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects.
Acetaminophen; Caffeine: (Minor) Patients taking benzodiazepines for insomnia should not use caffeine-containing products prior to going to bed as these products may antagonize the sedative effects of the benzodiazepine.
Acetaminophen; Caffeine; Dihydrocodeine: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Minor) Patients taking benzodiazepines for insomnia should not use caffeine-containing products prior to going to bed as these products may antagonize the sedative effects of the benzodiazepine.
Acetaminophen; Caffeine; Pyrilamine: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Minor) Patients taking benzodiazepines for insomnia should not use caffeine-containing products prior to going to bed as these products may antagonize the sedative effects of the benzodiazepine.
Acetaminophen; Chlorpheniramine: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Acetaminophen; Chlorpheniramine; Dextromethorphan: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Phenylephrine: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Acetaminophen; Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Acetaminophen; Chlorpheniramine; Phenylephrine : (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Acetaminophen; Codeine: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants.
Acetaminophen; Dextromethorphan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Acetaminophen; Dextromethorphan; Doxylamine: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of doxylamine and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects.
Acetaminophen; Dextromethorphan; Guaifenesin; Phenylephrine: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Acetaminophen; Dextromethorphan; Guaifenesin; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Acetaminophen; Dextromethorphan; Phenylephrine: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Acetaminophen; Dextromethorphan; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Acetaminophen; Dichloralphenazone; Isometheptene: (Major) Avoid use of tricyclic antidepressants with isometheptene, a sympathomimetic amine, whenever possible. Tricyclic antidepressants (TCAs) may potentiate the pressor response to sympathomimetic agents. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience side effects like hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. Patients should be closely monitored if use together is unavoidable. (Major) The CNS depressant effects of dichloralphenazone can be potentiated by tricyclic antidepressants.
Acetaminophen; Diphenhydramine: (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of diphenhydramine and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects.
Acetaminophen; Guaifenesin; Phenylephrine: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Acetaminophen; Hydrocodone: (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 hydrocodone is initiated in a patient taking a benzodiazepine, reduce initial dosage and titrate to clinical response; for hydrocodone extended-release products, initiate hydrocodone at 20% to 30% of 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. Avoid opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants.
Acetaminophen; Oxycodone: (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. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Acetaminophen; Pamabrom; Pyrilamine: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Acetaminophen; Phenylephrine: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Acetaminophen; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines.
Acetazolamide: (Moderate) Tricyclic antidepressants, when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions.
Acetylcholine Chloride: (Moderate) Tricyclic antidepressants (TCAs) may antagonize some of the effects of parasympathomimetics (e.g., cholinesterase inhibitors) due to their anticholinergic activity. However, parasympathomimetics like bethanechol have occasionally been used historically to offset some of the adverse peripheral antimuscarinic (anticholinergic) effects of TCAs, such as dry mouth, constipation, or urinary retention. For years, physostigmine was used as an adjunct to the treatment of TCA overdose; however, its efficacy was limited to addressing anticholinergic effects. Additionally, case reports suggest that harmful effects such as seizures and bradyarrhythmias progressing to asystole, especially in patients with cardiac conduction abnormalities at baseline, are possible. For these reasons, physostigmine is no longer considered a standard of care in the treatment of TCA overdose.
Acrivastine; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Clinicians should note that antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Adagrasib: (Moderate) Monitor for an increase in chlordiazepoxide-related adverse reactions including sedation and respiratory depression if coadministration with adagrasib is necessary; adjust the dose of chlordiazepoxide if necessary. Chlordiazepoxide is a CYP3A substrate; adagrasib is a strong CYP3A inhibitor. (Moderate) Monitor for an increase in tricyclic antidepressant (TCA)-related adverse reactions if coadministration with adagrasib is necessary; a dose reduction of TCA may be necessary. Concurrent use may increase the exposure of TCAs which are CYP2D6 substrates; adagrasib is a CYP2D6 inhibitor.
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 activity. Use with caution.
Alfentanil: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Alosetron: (Moderate) Alosetron, if combined with drugs that possess anticholinergic properties like tricyclic antidepressants, may seriously worsen constipation, leading to events such as GI obstruction/impaction or paralytic ileus.
Alprazolam: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur. (Moderate) Concomitant administration of alprazolam with CNS-depressant drugs can potentiate the CNS effects of either agent.
Amantadine: (Moderate) Additive anticholinergic effects and CNS effects may be seen when tricyclic antidepressants are used concomitantly with amantadine.
Amifampridine: (Major) Carefully consider the need for concomitant treatment with tricyclic antidepressants and amifampridine, as coadministration may increase the risk of seizures. If coadministration occurs, closely monitor patients for seizure activity. Seizures have been observed in patients without a history of seizures taking amifampridine at recommended doses. Tricyclic antidepressants may increase the risk of seizures.
Amiodarone: (Moderate) CYP3A4 inhibitors, such as amiodarone, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity.
Amlodipine; Celecoxib: (Moderate) Monitor for an increase in amitriptyline-related adverse reactions if coadministration with celecoxib is necessary; a dose reduction of amitriptyline may be necessary. Concurrent use may increase the plasma concentrations of amitriptyline. Amitriptyline is a CYP2D6 substrate and celecoxib is a CYP2D6 inhibitor.
Amobarbital: (Moderate) Additive CNS and/or respiratory depression may occur. Additionally, barbiturates may increase the metabolism of chlordiazepoxide. Chlordiazepoxide is a CYP3A4 substrate. Barbiturates are CYP3A4 inducers. (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. In addition, pharmacokinetic interactions may occur. Barbiturates may increase TCA metabolism. Monitor patients during concurrent use.
Amoxapine: (Major) The use of a heterocyclic antidepressant, such as amoxapine, with tricyclic antidepressants (TCAs) is not generally recommended due to the duplicative nature of therapy and the risk for side effects. Additive cardiac effects (e.g., tachycardia), CNS effects, or antimuscarinic effects may occur. Additive dry mouth, constipation, drowsiness, bladder difficulties, or changes in heart rate might be possible. (Moderate) Amoxapine may enhance the response to the effects of benzodiazepines and other CNS depressants. Patients should be warned of the possibility of drowsiness that may impair performance of potentially hazardous tasks such as driving an automobile or operating machinery.
Amoxicillin; Clarithromycin; Omeprazole: (Moderate) CYP3A4 inhibitors, such as clarithromycin, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. (Moderate) Omeprazole inhibits CYP2C19. There have been some case reports describing an interaction between omeprazole and benzodiazepines metabolized via the cytochrome P450 system, such as chlordiazepoxide. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole.
Amphetamine: (Moderate) Monitor blood pressure, heart rate, and for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant amphetamine and tricyclic antidepressant use. Adjust doses or use alternative therapy based on clinical response. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for potentiation of cardiovascular effects and serotonin syndrome. Amphetamines may enhance the activity of tricyclic antidepressants causing significant and sustained increases in amphetamine concentrations in the brain.
Amphetamine; Dextroamphetamine: (Moderate) Monitor blood pressure, heart rate, and for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant amphetamine and tricyclic antidepressant use. Adjust doses or use alternative therapy based on clinical response. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for potentiation of cardiovascular effects and serotonin syndrome. Amphetamines may enhance the activity of tricyclic antidepressants causing significant and sustained increases in amphetamine concentrations in the brain.
Amphetamines: (Moderate) Monitor blood pressure, heart rate, and for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant amphetamine and tricyclic antidepressant use. Adjust doses or use alternative therapy based on clinical response. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for potentiation of cardiovascular effects and serotonin syndrome. Amphetamines may enhance the activity of tricyclic antidepressants causing significant and sustained increases in amphetamine concentrations in the brain.
Apomorphine: (Moderate) Apomorphine causes significant somnolence. Concomitant administration of apomorphine and benzodiazepines could result in additive depressant effects. (Moderate) Use apomorphine and tricyclic antidepressants together with caution due to the risk of additive QT prolongation. Tricyclic antidepressants have been associated with QT prolongation, primarily in overdosage or when excessive plasma concentrations are encountered. Dose-related QTc prolongation is associated with therapeutic apomorphine exposure. Additive sedation is also possible during combined use of these agents.
Apraclonidine: (Moderate) Tricyclic antidepressants have been reported to blunt the hypotensive effects of systemic clonidine; it is not known whether or not the concomitant use of these agents with apraclonidine can reduce the intraocular pressure lowering effect. (Minor) No specific drug interactions were identified with systemic agents and apraclonidine during clinical trials. Theoretically, apraclonidine might potentiate the effects of CNS depressant drugs such as the anxiolytics, sedatives, and hypnotics, including barbiturates or benzodiazepines.
Aprepitant, Fosaprepitant: (Moderate) Use caution if amitriptyline and multi-day regimens of oral aprepitant are used concurrently and monitor for an increase in amitriptyline-related adverse effects, including QT prolongation and torsade de pointes (TdP), for several days after administration. Amitriptyline 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 amitriptyline. 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. Aprepitant is also a CYP2C9 inducer and amitriptyline is a CYP2C9 substrate. Administration of a CYP2C9 substrate, tolbutamide, on days 1, 4, 8, and 15 with a 3-day regimen of oral aprepitant (125 mg/80 mg/80 mg) decreased the tolbutamide AUC by 23% on day 4, 28% on day 8, and 15% on day 15. The AUC of tolbutamide was decreased by 8% on day 2, 16% on day 4, 15% on day 8, and 10% on day 15 when given prior to oral administration of aprepitant 40 mg on day 1, and on days 2, 4, 8, and 15. The effects of aprepitant on tolbutamide were not considered significant. (Moderate) Use caution if chlordiazepoxide and aprepitant, fosaprepitant are used concurrently and monitor for an increase in chlordiazepoxide-related adverse effects for several days after administration of a multi-day aprepitant regimen. Chlordiazepoxide 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 chlordiazepoxide. 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 125mg 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.
Aripiprazole: (Moderate) Monitor blood pressure and for unusual drowsiness and sedation during coadministration of aripiprazole and benzodiazepines. Intensity of sedation and orthostatic hypotension were greater with the combination of oral aripiprazole and lorazepam compared to aripiprazole alone. (Moderate) Monitor for unusual drowsiness and sedation during coadministration of aripiprazole and tricyclic antidepressants due to the risk for additive CNS depression.
Artemether; Lumefantrine: (Major) Artemether; lumefantrine is an inhibitor and the tricyclic antidepressants are substrates of the CYP2D6 isoenzyme; therefore, coadministration may lead to increased tricyclic antidepressant concentrations. Furthermore, although there are no studies examining the effects of artemether; lumefantrine in patients receiving other QT prolonging drugs, coadministration of such drugs may result in additive QT prolongation. Concomitant use of artemether; lumefantrine with drugs that may prolong the QT interval such as tricyclic antidepressants should be avoided. Consider ECG monitoring if tricyclic antidepressants must be used with or after artemether; lumefantrine treatment.
Articaine; Epinephrine: (Major) Avoid use of epinephrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the vasopressor effects of epinephrine.
Asenapine: (Moderate) Concurrent use of asenapine and tricyclic antidepressants should be avoided if possible. Asenapine has been associated with a risk for QT prolongation and torsade de pointes, and tricyclics at elevated serum concentrations may produce clinically significant prolongation of the QTc interval. In addition, there is a potential for other interactions, such as augmentation of CNS impairment or orthostatic hypotension. Further, in vitro studies indicate that CYP1A2 and CYP3A4 are involved in the metabolism of asenapine. Inhibitors of these isoenzymes such as imipramine may decrease the elimination of asenapine. During co-administration of a single 75 mg dose of imipramine and a single 5 mg dose of asenapine, the Cmax of asenapine was increased by 17% and the AUC was increased by 10%. No asenapine dose adjustments are required during combined use. (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 anxiolytics, sedatives, and hypnotics (including barbiturates), buprenorphine, buprenorphine; naloxone, butorphanol, dronabinol, THC, nabilone, nalbuphine, opiate agonists, pentazocine, acetaminophen; pentazocine, aspirin, ASA; pentazocine, and pentazocine; naloxone.
Aspirin, ASA; Butalbital; Caffeine: (Moderate) Additive CNS and/or respiratory depression may occur. Additionally, barbiturates may increase the metabolism of chlordiazepoxide. Chlordiazepoxide is a CYP3A4 substrate. Barbiturates are CYP3A4 inducers. (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. In addition, pharmacokinetic interactions may occur. Barbiturates may increase TCA metabolism. Monitor patients during concurrent use. (Minor) Patients taking benzodiazepines for insomnia should not use caffeine-containing products prior to going to bed as these products may antagonize the sedative effects of the benzodiazepine.
Aspirin, ASA; Caffeine: (Minor) Patients taking benzodiazepines for insomnia should not use caffeine-containing products prior to going to bed as these products may antagonize the sedative effects of the benzodiazepine.
Aspirin, ASA; Caffeine; Orphenadrine: (Moderate) Orphenadrine should be combined cautiously with tricyclic antidepressants due to the potential for additive anticholinergic and CNS depressant effects. Antimuscarinic effects might be seen on GI smooth muscle, bladder function, the eye, and temperature regulation. Consider an alternative skeletal muscle relaxant. (Minor) Patients taking benzodiazepines for insomnia should not use caffeine-containing products prior to going to bed as these products may antagonize the sedative effects of the benzodiazepine.
Aspirin, ASA; Carisoprodol: (Moderate) Concomitant use of carisoprodol with tricyclic antidepressants can result in additive CNS depression (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Aspirin, ASA; Carisoprodol; Codeine: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Moderate) Concomitant use of carisoprodol with tricyclic antidepressants can result in additive CNS depression (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Aspirin, ASA; Omeprazole: (Moderate) Omeprazole inhibits CYP2C19. There have been some case reports describing an interaction between omeprazole and benzodiazepines metabolized via the cytochrome P450 system, such as chlordiazepoxide. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole.
Aspirin, ASA; Oxycodone: (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. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Atazanavir: (Major) CYP3A4 inhibitors, such as protease inhibitors, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. A decrease in the chlordiazepoxide dose may be needed. (Moderate) According to the manufacturer, concurrent use of tricyclic antidepressants (TCAs) and atazanavir may result in elevated TCA plasma concentration, and could increase the potential for serious adverse effects. If these drugs are administered together, carefully titrate the TCA dose based on a clinical assessment of antidepressant response. Patients on a stable dose of TCA who start treatment with atazanavir should be monitored for TCA-associated anticholinergic effects (e.g., sedation, confusion, constipation). In addition to clinical monitoring, the manufacturer suggests obtaining TCA serum concentrations (where available) as an adjunct to assessing the potential for interactions.
Atazanavir; Cobicistat: (Major) CYP3A4 inhibitors, such as protease inhibitors, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. A decrease in the chlordiazepoxide dose may be needed. (Moderate) According to the manufacturer, concurrent use of tricyclic antidepressants (TCAs) and atazanavir may result in elevated TCA plasma concentration, and could increase the potential for serious adverse effects. If these drugs are administered together, carefully titrate the TCA dose based on a clinical assessment of antidepressant response. Patients on a stable dose of TCA who start treatment with atazanavir should be monitored for TCA-associated anticholinergic effects (e.g., sedation, confusion, constipation). In addition to clinical monitoring, the manufacturer suggests obtaining TCA serum concentrations (where available) as an adjunct to assessing the potential for interactions. (Moderate) Close monitoring for antidepressant response and careful dose titrations of the antidepressant therapy is recommended during coadministration of tricyclic antidepressants (TCAs) and cobicistat. Concurrent use may result in elevated TCA plasma concentrations. (Moderate) The plasma concentrations of chlordiazepoxide may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects is recommended during coadministration. Cobicistat is a strong CYP3A4 inhibitor, while chlordiazepoxide is a CYP3A4 substrate.
Atropine: (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and atropine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
Atropine; Difenoxin: (Moderate) Concomitant administration of benzodiazepines with CNS-depressant drugs, such as diphenoxylate/difenoxin, can potentiate the CNS effects of either agent. (Moderate) Concurrent administration can potentiate the CNS and respiratory depressant effects of diphenoxylate/difenoxin and the CNS depressant effects of the tricyclic antidepressant (TCA). Both TCAs and diphenoxylate/difenoxin may cause constipation. Use caution during coadministration. Cases of severe GI reactions including toxic megacolon and adynamic ileus have been rarely reported. In some cases, a dosage reduction of diphenoxylate or difenoxin might be needed to manage any noted side effects. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and atropine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
Azelastine: (Moderate) Monitor for excessive sedation and somnolence during coadministration of azelastine and benzodiazepines. Concurrent use may result in additive CNS depression. (Moderate) Monitor for excessive sedation and somnolence during coadministration of azelastine and tricyclic antidepressants. Concurrent use may result in additive CNS depression.
Azelastine; Fluticasone: (Moderate) Monitor for excessive sedation and somnolence during coadministration of azelastine and benzodiazepines. Concurrent use may result in additive CNS depression. (Moderate) Monitor for excessive sedation and somnolence during coadministration of azelastine and tricyclic antidepressants. Concurrent use may result in additive CNS depression.
Baclofen: (Moderate) Monitor for unusual drowsiness and excess sedation during coadministration of baclofen and tricyclic antidepressants due to the risk for additive CNS depression.
Barbiturates: (Moderate) Additive CNS and/or respiratory depression may occur. Additionally, barbiturates may increase the metabolism of chlordiazepoxide. Chlordiazepoxide is a CYP3A4 substrate. Barbiturates are CYP3A4 inducers. (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. In addition, pharmacokinetic interactions may occur. Barbiturates may increase TCA metabolism. Monitor patients during concurrent use.
Belladonna; Opium: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation, somnolence, and increased risk of serotonin syndrome. The anticholinergic properties of tricyclic antidepressants may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression and serotonin syndrome. Monitor for signs of urinary retention and reduced gastric motility. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and belladonna use. Concomitant use may result in additive anticholinergic adverse effects.
Benzhydrocodone; Acetaminophen: (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 benzhydrocodone is initiated in a patient taking a benzodiazepine, reduce initial dosage and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation, somnolence, and increased risk of serotonin syndrome. The anticholinergic properties of tricyclic antidepressants may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression and serotonin syndrome. Monitor for signs of urinary retention and reduced gastric motility.
Benzodiazepines: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur.
Benzoic Acid; Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate: (Contraindicated) Per the manufacturer, treatment initiation with amitriptyline is contraindicated in patients currently receiving intravenous (IV) methylene blue due to an increased risk of serotonin syndrome. If urgent psychiatric treatment is required, interventions other than amitriptyline (e.g., alternative medication, hospitalization) should be considered. Conversely, in patients receiving amitriptyline and requiring urgent treatment with IV methylene blue, amitriptyline should be discontinued immediately and methylene blue therapy initiated only if acceptable alternatives are not available and the potential benefits outweigh the risks. The patient should be monitored for serotonin syndrome for 2 weeks or until 24 hours after the last dose of methylene blue, whichever comes first. Amitriptyline may be re-initiated 24 hours after the last dose of methylene blue. Results from an in vitro study indicate that methylene blue is a potent, reversible inhibitor of the monoamine oxidase type A enzyme (MAO-A). MAO-A is responsible for the metabolism of serotonin. Cases of serotonin syndrome have been reported, primarily following administration of standard infusions of methylene blue (1 to 8 mg/kg) as a visualizing agent, in patients receiving serotonergic agents. It is not known if patients receiving other serotonergic psychiatric agents with IV methylene blue are at a comparable risk or if methylene blue administered by other routes (e.g., orally, local injection) or in doses less than 1 mg/kg IV can produce a similar outcome. Published interaction reports between IV methylene blue and serotonergic psychiatric agents have documented symptoms including lethargy, confusion, delirium, agitation, aggression, obtundation, myoclonus, expressive aphasia, hypertonia, pyrexia, elevated blood pressure, seizures, and/or coma. Signs and symptoms of serotonin syndrome include fever, diaphoresis, shivering, myoclonus, tremor, tachycardia, diarrhea, nausea, headache, incoordination, mental status changes (e.g., agitation, confusion), hyperreflexia, seizures, and coma. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects.
Benzphetamine: (Moderate) Monitor blood pressure, heart rate, and for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant amphetamine and tricyclic antidepressant use. Adjust doses or use alternative therapy based on clinical response. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for potentiation of cardiovascular effects and serotonin syndrome. Amphetamines may enhance the activity of tricyclic antidepressants causing significant and sustained increases in amphetamine concentrations in the brain.
Benztropine: (Moderate) CNS depressants, such as anxiolytics, sedatives, and hypnotics, can increase the sedative effects of benztropine. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and benztropine use. Concomitant use may result in additive anticholinergic adverse effects.
Berotralstat: (Moderate) Monitor for an increase in tricyclic antidepressant-related adverse reactions if coadministration with berotralstat is necessary; a dose reduction of the antidepressant may be necessary. Concurrent use may increase exposure of tricyclic antidepressants (TCAs). TCAs are CYP2D6 substrates and berotralstat is a CYP2D6 inhibitor.
Bethanechol: (Moderate) Tricyclic antidepressants (TCAs) may antagonize some of the effects of parasympathomimetics (e.g., cholinesterase inhibitors) due to their anticholinergic activity. However, parasympathomimetics like bethanechol have occasionally been used historically to offset some of the adverse peripheral antimuscarinic (anticholinergic) effects of TCAs, such as dry mouth, constipation, or urinary retention. For years, physostigmine was used as an adjunct to the treatment of TCA overdose; however, its efficacy was limited to addressing anticholinergic effects. Additionally, case reports suggest that harmful effects such as seizures and bradyarrhythmias progressing to asystole, especially in patients with cardiac conduction abnormalities at baseline, are possible. For these reasons, physostigmine is no longer considered a standard of care in the treatment of TCA overdose.
Brexanolone: (Moderate) Concomitant use of brexanolone with CNS depressants like the benzodiazepines may increase the likelihood or severity of adverse reactions related to sedation and additive CNS depression. Monitor for excessive sedation, dizziness, and a potential for loss of consciousness during brexanolone use.
Brexpiprazole: (Moderate) Due to the CNS effects of brexpiprazole, caution is advisable when brexpiprazole is given in combination with other centrally-acting medications including tricyclic antidepressants (TCAs). Sedation is generally more pronounced with tertiary TCAs such as amitriptyline, imipramine, doxepin, and clomipramine.
Brimonidine: (Moderate) Based on the sedative effects of brimonidine in individual patients, brimonidine administration has potential to enhance the CNS depressants effects of the anxiolytics, sedatives, and hypnotics including benzodiazepines. (Moderate) Tricyclic antidepressants have been reported to decrease the antihypertensive effects of systemic clonidine. It is not known whether tricyclic antidepressants will affect the IOP-lowering efficacy of brimonidine eye solution. There are no data concerning the levels of systemic catecholamines after ophthalmic administration of brimonidine; however, monitor patients carefully who are taking brimonidine and tricyclic antidepressants.
Brimonidine; Brinzolamide: (Moderate) Based on the sedative effects of brimonidine in individual patients, brimonidine administration has potential to enhance the CNS depressants effects of the anxiolytics, sedatives, and hypnotics including benzodiazepines. (Moderate) Tricyclic antidepressants have been reported to decrease the antihypertensive effects of systemic clonidine. It is not known whether tricyclic antidepressants will affect the IOP-lowering efficacy of brimonidine eye solution. There are no data concerning the levels of systemic catecholamines after ophthalmic administration of brimonidine; however, monitor patients carefully who are taking brimonidine and tricyclic antidepressants.
Brimonidine; Timolol: (Moderate) Based on the sedative effects of brimonidine in individual patients, brimonidine administration has potential to enhance the CNS depressants effects of the anxiolytics, sedatives, and hypnotics including benzodiazepines. (Moderate) Tricyclic antidepressants have been reported to decrease the antihypertensive effects of systemic clonidine. It is not known whether tricyclic antidepressants will affect the IOP-lowering efficacy of brimonidine eye solution. Th

ere are no data concerning the levels of systemic catecholamines after ophthalmic administration of brimonidine; however, monitor patients carefully who are taking brimonidine and tricyclic antidepressants.
Brivaracetam: (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. Monitor patients on anticonvulsants carefully when a TCA is used concurrently.
Brompheniramine: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Brompheniramine; Dextromethorphan; Phenylephrine: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Brompheniramine; Phenylephrine: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Brompheniramine; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Brompheniramine; Pseudoephedrine; Dextromethorphan: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Budesonide; Glycopyrrolate; Formoterol: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and glycopyrrolate use. Concomitant use may result in additive anticholinergic adverse effects.
Bupivacaine Liposomal: (Major) Coadminister bupivacaine and tricyclic antidepressants together with caution. If epinephrine is added to bupivacaine, severe and prolonged hypertension may occur in a patient taking a TCA. Tricyclic antidepressants can increase the sensitivity to epinephrine by inhibiting epinephrine reuptake or metabolism. If concurrent therapy is necessary, carefully monitor the patient.
Bupivacaine: (Major) Coadminister bupivacaine and tricyclic antidepressants together with caution. If epinephrine is added to bupivacaine, severe and prolonged hypertension may occur in a patient taking a TCA. Tricyclic antidepressants can increase the sensitivity to epinephrine by inhibiting epinephrine reuptake or metabolism. If concurrent therapy is necessary, carefully monitor the patient.
Bupivacaine; Epinephrine: (Major) Avoid use of epinephrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the vasopressor effects of epinephrine. (Major) Coadminister bupivacaine and tricyclic antidepressants together with caution. If epinephrine is added to bupivacaine, severe and prolonged hypertension may occur in a patient taking a TCA. Tricyclic antidepressants can increase the sensitivity to epinephrine by inhibiting epinephrine reuptake or metabolism. If concurrent therapy is necessary, carefully monitor the patient.
Bupivacaine; Lidocaine: (Major) Coadminister bupivacaine and tricyclic antidepressants together with caution. If epinephrine is added to bupivacaine, severe and prolonged hypertension may occur in a patient taking a TCA. Tricyclic antidepressants can increase the sensitivity to epinephrine by inhibiting epinephrine reuptake or metabolism. If concurrent therapy is necessary, carefully monitor the patient. (Major) If epinephrine is added to lidocaine for the purpose of infiltration and nerve block or spinal anesthesia, receipt of the product to a patient taking tricyclic antidepressants (TCA) may lead to severe, prolonged hypertension. In general, concurrent use of a local anesthetic solution containing epinephrine and a TCA should be avoided. If coadministration is necessary, careful patient monitoring is essential.
Bupivacaine; Meloxicam: (Major) Coadminister bupivacaine and tricyclic antidepressants together with caution. If epinephrine is added to bupivacaine, severe and prolonged hypertension may occur in a patient taking a TCA. Tricyclic antidepressants can increase the sensitivity to epinephrine by inhibiting epinephrine reuptake or metabolism. If concurrent therapy is necessary, carefully monitor the patient.
Buprenorphine: (Major) Concomitant use of mixed opiate agonists/antagonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of mixed opiate agonists/antagonists 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 a mixed opiate agonist/antagonist is initiated for pain in a patient taking a benzodiazepine, use a lower initial dose of the mixed opiate agonist/antagonist and titrate to clinical response. Reduce injectable buprenorphine dose by 1/2, and for the buprenorphine transdermal patch, start therapy with the 5 mcg/hour patch. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking a mixed opiate agonist/antagonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. In patients treated with buprenorphine for opioid use disorder, cessation of benzodiazepines or other CNS depressants is preferred in most cases. Consider alternatives to benzodiazepines for conditions such as anxiety or insomnia in patients receiving buprenorphine maintenance treatment. Educate patients about the risks and symptoms of respiratory depression and sedation. (Major) Concomitant use of tricyclic antidepressants (TCAs) and buprenorphine increases the risk of QT/QTc prolongation, torsade de pointes (TdP), serotonin syndrome, hypotension, profound sedation, coma, respiratory depression, or death. Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. In addition, concurrent use of opioids with other drugs that modulate serotonergic function, such as TCAs, has resulted in serotonin syndrome in some cases. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. If combination treatment is required, patients should be carefully observed, particularly during treatment initiation and during dose adjustments of the serotonergic drug; discontinue buprenorphine if serotonin syndrome is suspected. Lastly, concomitant use of buprenorphine with other CNS depressants, such as TCAs, can lead to additive CNS depressive effects. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Prior to concurrent use of buprenorphine in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Evaluate the patient's use of alcohol or illicit drugs. Consider a dose reduction of one or both drugs. It is recommended that the injectable buprenorphine dose be halved for patients who receive other drugs with CNS depressant effects; for the buprenorphine transdermal patch, start with the 5 mcg/hour patch. Monitor patients for sedation or respiratory depression.
Buprenorphine; Naloxone: (Major) Concomitant use of mixed opiate agonists/antagonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of mixed opiate agonists/antagonists 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 a mixed opiate agonist/antagonist is initiated for pain in a patient taking a benzodiazepine, use a lower initial dose of the mixed opiate agonist/antagonist and titrate to clinical response. Reduce injectable buprenorphine dose by 1/2, and for the buprenorphine transdermal patch, start therapy with the 5 mcg/hour patch. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking a mixed opiate agonist/antagonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. In patients treated with buprenorphine for opioid use disorder, cessation of benzodiazepines or other CNS depressants is preferred in most cases. Consider alternatives to benzodiazepines for conditions such as anxiety or insomnia in patients receiving buprenorphine maintenance treatment. Educate patients about the risks and symptoms of respiratory depression and sedation. (Major) Concomitant use of tricyclic antidepressants (TCAs) and buprenorphine increases the risk of QT/QTc prolongation, torsade de pointes (TdP), serotonin syndrome, hypotension, profound sedation, coma, respiratory depression, or death. Avoid concomitant use if possible, especially in patients with additional risk factors for TdP. Consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, if concomitant use is necessary. In addition, concurrent use of opioids with other drugs that modulate serotonergic function, such as TCAs, has resulted in serotonin syndrome in some cases. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. If combination treatment is required, patients should be carefully observed, particularly during treatment initiation and during dose adjustments of the serotonergic drug; discontinue buprenorphine if serotonin syndrome is suspected. Lastly, concomitant use of buprenorphine with other CNS depressants, such as TCAs, can lead to additive CNS depressive effects. Hypotension, profound sedation, coma, respiratory depression, or death may occur. Prior to concurrent use of buprenorphine in patients taking a CNS depressant, assess the level of tolerance to CNS depression that has developed, the duration of use, and the patient's overall response to treatment. Evaluate the patient's use of alcohol or illicit drugs. Consider a dose reduction of one or both drugs. It is recommended that the injectable buprenorphine dose be halved for patients who receive other drugs with CNS depressant effects; for the buprenorphine transdermal patch, start with the 5 mcg/hour patch. Monitor patients for sedation or respiratory depression.
Bupropion: (Moderate) Use extreme caution when coadministering bupropion with other drugs that lower the seizure threshold, such as tricyclic antidepressants. Use low initial doses of bupropion and increase the dose gradually. Monitor patients for an increase in tricyclic antidepressant-related adverse reactions and signs and symptoms of serotonin syndrome during concomitant use, particularly during treatment initiation and dosage increases; a dose reduction of the tricyclic antidepressant may be necessary. If serotonin syndrome occurs, consider discontinuation of therapy. The concomitant use of serotonergic drugs increases the risk of serotonin syndrome. Tricyclic antidepressants are CYP2D6 substrates and bupropion is a CYP2D6 inhibitor.
Bupropion; Naltrexone: (Moderate) Use extreme caution when coadministering bupropion with other drugs that lower the seizure threshold, such as tricyclic antidepressants. Use low initial doses of bupropion and increase the dose gradually. Monitor patients for an increase in tricyclic antidepressant-related adverse reactions and signs and symptoms of serotonin syndrome during concomitant use, particularly during treatment initiation and dosage increases; a dose reduction of the tricyclic antidepressant may be necessary. If serotonin syndrome occurs, consider discontinuation of therapy. The concomitant use of serotonergic drugs increases the risk of serotonin syndrome. Tricyclic antidepressants are CYP2D6 substrates and bupropion is a CYP2D6 inhibitor.
Buspirone: (Moderate) Coadministration of buspirone with tricyclic antidepressants (TCAs) may increase the risk of serotonin syndrome. Both types of medications have serotonergic properties. Inform patients of the possible increased risk and monitor for the emergence of serotonin syndrome, particularly during treatment initiation and dose increases. If serotonin syndrome occurs, all serotonergic drugs should be discontinued and appropriate medical treatment should be initiated. (Moderate) It is common for patients to overlap anxiety treatment when switching from benzodiazepines to buspirone. Buspirone has a slow onset of action and the drug will not block the withdrawal syndrome often seen with cessation of benzodiazepine therapy in those with benzodiazepine dependence. Therefore, before starting therapy with buspirone, withdraw patients gradually from the benzodiazepine. Alternatively, conversion to buspirone therapy may require treatment overlap to allow for the downward titration of the benzodiazepine while buspirone takes effect. It should be noted that the combination of buspirone and benzodiazepines can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent.
Butabarbital: (Moderate) Additive CNS and/or respiratory depression may occur. Additionally, barbiturates may increase the metabolism of chlordiazepoxide. Chlordiazepoxide is a CYP3A4 substrate. Barbiturates are CYP3A4 inducers. (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. In addition, pharmacokinetic interactions may occur. Barbiturates may increase TCA metabolism. Monitor patients during concurrent use.
Butalbital; Acetaminophen: (Moderate) Additive CNS and/or respiratory depression may occur. Additionally, barbiturates may increase the metabolism of chlordiazepoxide. Chlordiazepoxide is a CYP3A4 substrate. Barbiturates are CYP3A4 inducers. (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. In addition, pharmacokinetic interactions may occur. Barbiturates may increase TCA metabolism. Monitor patients during concurrent use.
Butalbital; Acetaminophen; Caffeine: (Moderate) Additive CNS and/or respiratory depression may occur. Additionally, barbiturates may increase the metabolism of chlordiazepoxide. Chlordiazepoxide is a CYP3A4 substrate. Barbiturates are CYP3A4 inducers. (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. In addition, pharmacokinetic interactions may occur. Barbiturates may increase TCA metabolism. Monitor patients during concurrent use. (Minor) Patients taking benzodiazepines for insomnia should not use caffeine-containing products prior to going to bed as these products may antagonize the sedative effects of the benzodiazepine.
Butalbital; Acetaminophen; Caffeine; Codeine: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Moderate) Additive CNS and/or respiratory depression may occur. Additionally, barbiturates may increase the metabolism of chlordiazepoxide. Chlordiazepoxide is a CYP3A4 substrate. Barbiturates are CYP3A4 inducers. (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. In addition, pharmacokinetic interactions may occur. Barbiturates may increase TCA metabolism. Monitor patients during concurrent use. (Minor) Patients taking benzodiazepines for insomnia should not use caffeine-containing products prior to going to bed as these products may antagonize the sedative effects of the benzodiazepine.
Butalbital; Aspirin; Caffeine; Codeine: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Moderate) Additive CNS and/or respiratory depression may occur. Additionally, barbiturates may increase the metabolism of chlordiazepoxide. Chlordiazepoxide is a CYP3A4 substrate. Barbiturates are CYP3A4 inducers. (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. In addition, pharmacokinetic interactions may occur. Barbiturates may increase TCA metabolism. Monitor patients during concurrent use. (Minor) Patients taking benzodiazepines for insomnia should not use caffeine-containing products prior to going to bed as these products may antagonize the sedative effects of the benzodiazepine.
Butorphanol: (Major) Concomitant use of mixed opiate agonists/antagonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of mixed opiate agonists/antagonists 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 a mixed opiate agonist/antagonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the mixed opiate agonist/antagonist and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking a mixed opiate agonist/antagonist, 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) Pain medications such as mixed opiate agonists/antagonists should be combined cautiously with tricyclic antidepressants due to the possibility of additive CNS depression, respiratory depression, hypotension, or decreased intestinal motility. Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering tricyclic antidepressants with other drugs that have serotonergic properties such as pentazocine. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. If serotonin syndrome is suspected, tricyclic antidepressants and concurrent serotonergic agents should be discontinued. If a CNS depressant needs to be used with butorphanol, use the smallest effective dose and the longest dosing frequency of butorphanol.
Caffeine: (Minor) Patients taking benzodiazepines for insomnia should not use caffeine-containing products prior to going to bed as these products may antagonize the sedative effects of the benzodiazepine.
Caffeine; Sodium Benzoate: (Minor) Patients taking benzodiazepines for insomnia should not use caffeine-containing products prior to going to bed as these products may antagonize the sedative effects of the benzodiazepine.
Calcium, Magnesium, Potassium, Sodium Oxybates: (Contraindicated) Sodium oxybate should not be used in combination with CNS depressant anxiolytics, sedatives, and hypnotics or other sedative CNS depressant drugs. Specifically, sodium oxybate use is contraindicated in patients being treated with sedative hypnotic drugs. Sodium oxybate (GHB) has the potential to impair cognitive and motor skills. For example, the concomitant use of barbiturates and benzodiazepines increases sleep duration and may contribute to rapid onset, pronounced CNS depression, respiratory depression, or coma when combined with sodium oxybate.
Cannabidiol: (Moderate) Monitor for excessive sedation and somnolence during coadministration of cannabidiol and amitriptyline. Concurrent use may result in additive CNS depression. (Moderate) Monitor for excessive sedation and somnolence during coadministration of cannabidiol and chlordiazepoxide. CNS depressants can potentiate the effects of cannabidiol.
Capsaicin; Metaxalone: (Moderate) Coadministration of tricyclic antidepressants (TCAs) with metaxalone may result in additive CNS-depressant effects, such as sedation, and may increase the risk for serotonin syndrome. Use with caution and monitor for the emergence of excessive sedation or serotonin syndrome. If serotonin syndrome is suspected, serotonergic agents should be discontinued and appropriate medical treatment instituted.
Carbamazepine: (Moderate) Hepatic inducers, such as carbamazepine, can theoretically increase the clearance of benzodiazepines metabolized by oxidative metabolism, leading to lower benzodiazepine concentrations. (Moderate) Monitor for loss of tricyclic antidepressant efficacy during concomitant carbamazepine use. Concomitant use may result in decreased tricyclic antidepressant exposure.
Carbidopa; Levodopa: (Moderate) Monitor blood pressure and for symptoms of dyskinesia during concomitant levodopa and tricyclic antidepressant use. There have been rare reports of adverse reactions, including hypertension and dyskinesia, resulting from the concomitant use.
Carbidopa; Levodopa; Entacapone: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tricyclic antidepressants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them. (Moderate) Monitor blood pressure and for symptoms of dyskinesia during concomitant levodopa and tricyclic antidepressant use. There have been rare reports of adverse reactions, including hypertension and dyskinesia, resulting from the concomitant use.
Carbinoxamine: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Cariprazine: (Moderate) Due to the CNS effects of cariprazine, caution is advisable when cariprazine is given in combination with other centrally-acting medications including tricyclic antidepressants. Sedation is generally more pronounced with tertiary agents such as amitriptyline, imipramine, doxepin, and clomipramine. (Moderate) Due to the CNS effects of cariprazine, caution should be used when cariprazine is given in combination with other centrally-acting medications including benzodiazepines and other anxiolytics, sedatives, and hypnotics.
Carisoprodol: (Moderate) Concomitant use of carisoprodol with tricyclic antidepressants can result in additive CNS depression (sedation and dizziness), which can impair the ability to undertake tasks requiring mental alertness.
Celecoxib: (Moderate) Monitor for an increase in amitriptyline-related adverse reactions if coadministration with celecoxib is necessary; a dose reduction of amitriptyline may be necessary. Concurrent use may increase the plasma concentrations of amitriptyline. Amitriptyline is a CYP2D6 substrate and celecoxib is a CYP2D6 inhibitor.
Celecoxib; Tramadol: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. (Major) Concomitant use of tramadol with tricyclic antidepressants may cause respiratory depression, hypotension, profound sedation, and death and increase the risk for serotonin syndrome, seizures, and anticholinergic effects. Limit the use of opioid pain medications to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Monitor patients for serotonin syndrome if concomitant use is necessary, particularly during treatment initiation and dosage increases. If serotonin syndrome occurs, consider discontinuation of therapy. The concomitant use of serotonergic drugs increases the risk of serotonin syndrome. Monitor for signs of urinary retention or reduced gastric motility during coadministration. The concomitant use of anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. (Moderate) Monitor for an increase in amitriptyline-related adverse reactions if coadministration with celecoxib is necessary; a dose reduction of amitriptyline may be necessary. Concurrent use may increase the plasma concentrations of amitriptyline. Amitriptyline is a CYP2D6 substrate and celecoxib is a CYP2D6 inhibitor.
Cenobamate: (Moderate) Monitor for excessive sedation and somnolence during coadministration of cenobamate and benzodiazepines. Concurrent use may result in additive CNS depression. (Moderate) Monitor for excessive sedation and somnolence during coadministration of cenobamate and tricyclic antidepressants. Concurrent use may result in additive CNS depression.
Ceritinib: (Moderate) Monitor for an increase in sedation and respiratory depression if coadministration of chlordiazepoxide with ceritinib is necessary. Chlordiazepoxide is a CYP3A4 substrate and ceritinib is a strong CYP3A4 inhibitor.
Cetirizine: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence. (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of cetirizine and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects.
Cetirizine; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence. (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of cetirizine and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects.
Cevimeline: (Moderate) Tricyclic antidepressants (TCAs) may antagonize some of the effects of parasympathomimetics (e.g., cholinesterase inhibitors) due to their anticholinergic activity. However, parasympathomimetics like bethanechol have occasionally been used historically to offset some of the adverse peripheral antimuscarinic (anticholinergic) effects of TCAs, such as dry mouth, constipation, or urinary retention. For years, physostigmine was used as an adjunct to the treatment of TCA overdose; however, its efficacy was limited to addressing anticholinergic effects. Additionally, case reports suggest that harmful effects such as seizures and bradyarrhythmias progressing to asystole, especially in patients with cardiac conduction abnormalities at baseline, are possible. For these reasons, physostigmine is no longer considered a standard of care in the treatment of TCA overdose.
Chlophedianol; Dexbrompheniramine: (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Chlophedianol; Dexchlorpheniramine; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Chlorcyclizine: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Chlordiazepoxide: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur.
Chlordiazepoxide; Clidinium: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur.
Chlorpheniramine: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Chlorpheniramine; Codeine: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Chlorpheniramine; Dextromethorphan: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Chlorpheniramine; Dextromethorphan; Phenylephrine: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Chlorpheniramine; Dextromethorphan; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Chlorpheniramine; Dihydrocodeine; Phenylephrine: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Chlorpheniramine; Hydrocodone: (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 hydrocodone is initiated in a patient taking a benzodiazepine, reduce initial dosage and titrate to clinical response; for hydrocodone extended-release products, initiate hydrocodone at 20% to 30% of 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. Avoid opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Chlorpheniramine; Ibuprofen; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Chlorpheniramine; Phenylephrine: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Chlorpheniramine; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Chlorpromazine: (Moderate) During coadministration of tricyclic antidepressants (TCAs) and chlorpromazine, close monitoring is essential and dose reduction may become necessary to avoid toxicity. Chlorpromazine is associated with an established risk of QT prolongation and torsades de pointes (TdP); case reports have included patients receiving therapeutic doses of chlorpromazine. TCAs may cause cardiac effects (e.g., QT prolongation) in some cases. Additive anticholinergic effects, hypotension, and sedation may also occur.
Chlorthalidone; Clonidine: (Moderate) Clonidine has CNS depressive effects and can potentiate the actions of other CNS depressants including benzodiazepines. (Moderate) Monitor blood pressure and for unusual drowsiness or excess sedation during coadministration of clonidine and tricyclic antidepressants. Concomitant use may result in reduced hypotensive effect of clonidine and additive CNS depression.
Chlorzoxazone: (Moderate) Concomitant use of chlorzoxazone with tricyclic antidepressants can result in additive CNS depression.
Cholinergic agonists: (Moderate) Tricyclic antidepressants (TCAs) may antagonize some of the effects of parasympathomimetics (e.g., cholinesterase inhibitors) due to their anticholinergic activity. However, parasympathomimetics like bethanechol have occasionally been used historically to offset some of the adverse peripheral antimuscarinic (anticholinergic) effects of TCAs, such as dry mouth, constipation, or urinary retention. For years, physostigmine was used as an adjunct to the treatment of TCA overdose; however, its efficacy was limited to addressing anticholinergic effects. Additionally, case reports suggest that harmful effects such as seizures and bradyarrhythmias progressing to asystole, especially in patients with cardiac conduction abnormalities at baseline, are possible. For these reasons, physostigmine is no longer considered a standard of care in the treatment of TCA overdose.
Cimetidine: (Moderate) Cimetidine can inhibit the hepatic clearance of some benzodiazepines that undergo oxidative metabolism, including chlordiazepoxide. (Moderate) Monitor for an increase in amitriptyline-related adverse reactions if coadministration with cimetidine is necessary; a dose reduction of amitriptyline may be necessary. Concurrent use may increase the plasma concentrations of amitriptyline. Amitriptyline is a CYP2D6 substrate and cimetidine is a CYP2D6 inhibitor.
Cinacalcet: (Moderate) Monitor for an increase in tricyclic antidepressant (TCA)-related adverse reactions if coadministration with cinacalcet is necessary; a dose reduction of TCA may be necessary. Concurrent use may increase the exposure of TCAs which are CYP2D6 substrates; cinacalcet is a CYP2D6 inhibitor.
Ciprofloxacin: (Major) Ciprofloxacin is a CYP3A4 inhibitor and may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity.
Cisapride: (Moderate) Cisapride may enhance the sedative effects of benzodiazepines. Patients should not drive or operate heavy machinery until they know how the combination affects them. Patient counseling is important, as cisapride alone does not cause drowsiness or affect psychomotor function.
Citalopram: (Major) The use of tricyclic antidepressants (TCAs) and citalopram together may increase the risk of QT prolongation and serotonin syndrome; consider a decreased dosage of the TCA or the avoidance of concomitant SSRI therapy. If concomitant use is necessary, consider taking steps to minimize the risk for QT/QTc interval prolongation and TdP, such as electrolyte monitoring and repletion and ECG monitoring, and monitor for serotonin syndrome. If serotonin syndrome is suspected, discontinue all serotonergic agents. Citalopram is a weak inhibitor of CYP2D6 that has been associated with a risk of QT prolongation and torsade de pointes (TdP). CYP2D6 is responsible for metabolism of many of the TCAs; elevated TCA concentrations may potentially occur. TCAs share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations).
Clarithromycin: (Moderate) CYP3A4 inhibitors, such as clarithromycin, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity.
Clemastine: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Clobazam: (Major) Use clobazam with other benzodiazepines with caution due to the risk for additive CNS depression. (Moderate) A dosage reduction of CYP2D6 substrates, such tricyclic antidepressants, may be necessary during co-administration of clobazam. Limited in vivo data suggest that clobazam is an inhibitor of CYP2D6. Additive CNS depressant effects are possible when clobazam is administered concurrently with tricyclic antidepressants.
Clonazepam: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur.
Clonidine: (Moderate) Clonidine has CNS depressive effects and can potentiate the actions of other CNS depressants including benzodiazepines. (Moderate) Monitor blood pressure and for unusual drowsiness or excess sedation during coadministration of clonidine and tricyclic antidepressants. Concomitant use may result in reduced hypotensive effect of clonidine and additive CNS depression.
Clorazepate: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur.
Clozapine: (Moderate) Concurrent use of clozapine and tricyclic antidepressants should be avoided if possible. Treatment with clozapine has been associated with QT prolongation, torsade de pointes (TdP), cardiac arrest, and sudden death. Tricyclic antidepressants have a possible risk of QT prolongation (particularly with elevated concentrations). The manufacturer of clozapine recommends caution during concurrent use with medications known to cause QT prolongation. Anticholinergic effects may be seen when clozapine is used concomitantly with other drugs known to possess antimuscarinic activity like tricyclic antidepressants. Anticholinergic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Additive hypotension or sedation is also possible when clozapine is combined with these drugs. Anticholinergic effects are most prominent with tertiary TCAs such as amitriptyline, clomipramine, imipramine, trimipramine, and doxepin. (Moderate) If concurrent therapy with clozapine and a benzodiazepine is necessary, it is advisable to begin with the lowest possible benzodiazepine dose and closely monitor the patient, particularly at initiation of treatment and following dose increases. Although the combination has been used safely, adverse reactions such as confusion, ataxia, somnolence, delirium, collapse, cardiac arrest, respiratory arrest, and death have occurred rarely in patients receiving clozapine concurrently or following benzodiazepine therapy. Several benzodiazepines, including clonazepam, oxazepam, flurazepam, diazepam, clobazam, flunitrazepam, and lorazepam have been implicated in these reactions. At least one case of sudden death was reported following intravenous administration of lorazepam to a patient receiving clozapine.
Cobicistat: (Moderate) Close monitoring for antidepressant response and careful dose titrations of the antidepressant therapy is recommended during coadministration of tricyclic antidepressants (TCAs) and cobicistat. Concurrent use may result in elevated TCA plasma concentrations. (Moderate) The plasma concentrations of chlordiazepoxide may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects is recommended during coadministration. Cobicistat is a strong CYP3A4 inhibitor, while chlordiazepoxide is a CYP3A4 substrate.
Cocaine: (Moderate) Monitor patients for increased CNS stimulation during coadministration of cocaine and tricyclic antidepressants (TCAs). Concurrent use of cocaine and TCAs may increase the risk for excessive sympathetic CNS activity leading to symptoms such as tachycardia, hypertension, diaphoresis, agitation, cardiac arrythmias, or convulsions.
Codeine: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants.
Codeine; Guaifenesin: (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 w hom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants.
Codeine; Guaifenesin; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants.
Codeine; Phenylephrine; Promethazine: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant promethazine and tricyclic antidepressant use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Codeine; Promethazine: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. Avoid prescribing opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant promethazine and tricyclic antidepressant use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
COMT inhibitors: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tricyclic antidepressants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them. (Major) Concomitant administration of benzodiazepines with other drugs have CNS depressant properties, including COMT inhibitors, can potentiate the CNS effects of either agent. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Conjugated Estrogens: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Conjugated Estrogens; Bazedoxifene: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Conjugated Estrogens; Medroxyprogesterone: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Cyclizine: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Cyclobenzaprine: (Moderate) Monitor for unusual drowsiness, sedation, signs of anticholinergic toxicity, and serotonin syndrome during coadministration of cyclobenzaprine and tricyclic antidepressants. Concomitant use may increase the risk for additive CNS depression, anticholinergic adverse events, and serotonin syndrome. If serotonin syndrome occurs, consider discontinuation of therapy.
Cyproheptadine: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Dacomitinib: (Moderate) Monitor for an increase in tricyclic antidepressant (TCA)-related adverse reactions if coadministration with dacomitinib is necessary; a dose reduction of TCA may be necessary. Concurrent use may increase the exposure of TCAs which are CYP2D6 substrates; dacomitinib is a CYP2D6 inhibitor.
Danazol: (Moderate) Danazol is a CYP3A4 inhibitor and can theoretically reduce the metabolism of CYP3A4 substrates, including chlordiazepoxide.
Dantrolene: (Moderate) Concomitant use of dantrolene with tricyclic antidepressants can result in additive CNS depression.
Daridorexant: (Major) Monitor for excessive sedation and somnolence during use of daridorexant with benzodiazepines. Dosage adjustments may be necessary when administered together because of potentially additive CNS effects. Use of more than 2 hypnotics should be avoided due to the additive CNS depressant and complex sleep-related behaviors that may occur. While anxiolytic medications may be used concurrently with daridorexant, a reduction in dose of one or both agents may be needed. The risk of next-day impairment, including impaired driving, is increased if daridorexant is taken with other CNS depressants. (Moderate) Monitor for excessive sedation and somnolence during coadministration of daridorexant and tricyclic antidepressants. Dosage adjustments of daridorexant and the tricyclic antidepressant may be necessary when administered together because of potentially additive CNS effects. The risk of next-day impairment, including impaired driving, is increased if daridorexant is taken with other CNS depressants.
Darifenacin: (Moderate) The exposure to tricyclic antidepressants (TCAs) may be increased when coadministered with darifenacin. Appropriate monitoring and dose adjustment may be necessary. Darifenacin is a moderate CYP2D6 inhibitor; TCAs are CYP2D6 substrates.
Darunavir: (Major) Coadministration of darunavir and amitriptyline may result in increased amitriptyline plasma concentrations. Darunavir inhibits CYP3A. When administered as approved by the FDA (i.e., 'boosted' with ritonavir), further inhibition of CYP3A is seen and clinically significant drug interactions are expected with CYP3A substrates. Darunavir plus ritonavir is also an inhibitor of CYP2D6. Monitor for increased tricyclic antidepressant (TCA) adverse effects, such as nausea, dizziness, hypotension, and syncope, and consider a lower dose of amitriptyline with concurrent use. Amitriptyline is metabolized by CYP2D6 and also partially metabolized by CYP3A4. (Major) CYP3A4 inhibitors, such as protease inhibitors, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. A decrease in the chlordiazepoxide dose may be needed.
Darunavir; Cobicistat: (Major) Coadministration of darunavir and amitriptyline may result in increased amitriptyline plasma concentrations. Darunavir inhibits CYP3A. When administered as approved by the FDA (i.e., 'boosted' with ritonavir), further inhibition of CYP3A is seen and clinically significant drug interactions are expected with CYP3A substrates. Darunavir plus ritonavir is also an inhibitor of CYP2D6. Monitor for increased tricyclic antidepressant (TCA) adverse effects, such as nausea, dizziness, hypotension, and syncope, and consider a lower dose of amitriptyline with concurrent use. Amitriptyline is metabolized by CYP2D6 and also partially metabolized by CYP3A4. (Major) CYP3A4 inhibitors, such as protease inhibitors, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. A decrease in the chlordiazepoxide dose may be needed. (Moderate) Close monitoring for antidepressant response and careful dose titrations of the antidepressant therapy is recommended during coadministration of tricyclic antidepressants (TCAs) and cobicistat. Concurrent use may result in elevated TCA plasma concentrations. (Moderate) The plasma concentrations of chlordiazepoxide may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects is recommended during coadministration. Cobicistat is a strong CYP3A4 inhibitor, while chlordiazepoxide is a CYP3A4 substrate.
Darunavir; Cobicistat; Emtricitabine; Tenofovir alafenamide: (Major) Coadministration of darunavir and amitriptyline may result in increased amitriptyline plasma concentrations. Darunavir inhibits CYP3A. When administered as approved by the FDA (i.e., 'boosted' with ritonavir), further inhibition of CYP3A is seen and clinically significant drug interactions are expected with CYP3A substrates. Darunavir plus ritonavir is also an inhibitor of CYP2D6. Monitor for increased tricyclic antidepressant (TCA) adverse effects, such as nausea, dizziness, hypotension, and syncope, and consider a lower dose of amitriptyline with concurrent use. Amitriptyline is metabolized by CYP2D6 and also partially metabolized by CYP3A4. (Major) CYP3A4 inhibitors, such as protease inhibitors, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. A decrease in the chlordiazepoxide dose may be needed. (Moderate) Close monitoring for antidepressant response and careful dose titrations of the antidepressant therapy is recommended during coadministration of tricyclic antidepressants (TCAs) and cobicistat. Concurrent use may result in elevated TCA plasma concentrations. (Moderate) The plasma concentrations of chlordiazepoxide may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects is recommended during coadministration. Cobicistat is a strong CYP3A4 inhibitor, while chlordiazepoxide is a CYP3A4 substrate.
Delavirdine: (Major) Delavirdine inhibits CYP2D6 and may increase concentrations of other drugs metabolized by this enzyme, such as tricyclic antidepressants (TCAs). Monitor the patient for side effects associated with TCAs such as an increase in constipation, urinary difficulty, dizziness, or rarely, fast, irregular heartbeat. A dosage adjustment may be needed for TCAs when given concurrently with delavirdine. (Moderate) Delavirdine is a CYP3A4 inhibitor and may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity.
Desflurane: (Moderate) Concurrent use with benzodiazepines can decrease the minimum alveolar concentration (MAC) of desflurane needed to produce anesthesia. (Minor) Tricyclic antidepressants (TCAs) should be used cautiously and with close monitoring with halogenated anesthetics. Halogenated anesthetics can prolong the QT interval. Tricyclic antidepressants (TCAs) share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). In addition, general anesthetics may produce additive CNS depression when used in patients taking tricyclic antidepressants.
Desloratadine; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines.
Desmopressin: (Moderate) Additive hyponatremic effects may be seen in patients treated with desmopressin and drugs associated with SIADH including tricyclic antidepressants. Hyponatremia-induced convulsions have been rarely reported when imipramine and desmopressin are used concomitantly. Use these drugs together with caution, and monitor patients for signs and symptoms of hyponatremia.
Desogestrel; Ethinyl Estradiol: (Minor) Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines. (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Desvenlafaxine: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering serotonin norepinephrine reuptake inhibitors (SNRIs) with other drugs that have serotonergic properties such as tricyclic antidepressants (TCAs). Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. If serotonin syndrome is suspected, desvenlafaxine and concurrent serotonergic agents should be discontinued. Dosage adjustments of TCAs may be necessary during concurrent use of desvenlafaxine. Although clinical studies have shown that desvenlafaxine does not have a clinically relevant effect on CYP2D6 inhibition at doses of 100 mg/day, the manufacturer recommends that primary substrates of CYP2D6, such as desipramine, doxepin, clomipramine, and imipramine be dosed at the original level when coadministered with desvenlafaxine 100 mg or lower, or when desvenlafaxine is discontinued. The dose of these CYP2D6 substrates should be reduced by up to one-half if coadministered with desvenlafaxine 400 mg/day.
Deutetrabenazine: (Moderate) Advise patients that concurrent use of deutetrabenazine and drugs that can cause CNS depression, such as chlordiazepoxide, may have additive effects and worsen drowsiness or sedation. (Moderate) The risk of QT prolongation may be increased with coadministration of deutetrabenazine and tricyclic antidepressants (TCAs). Deutetrabenazine may prolong the QT interval, but the degree of QT prolongation is not clinically significant when deutetrabenazine is administered within the recommended dosage range. TCAs share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). Monitor for excessive sedation and somnolence during coadministration of TCAs and deutetrabenazine. Concurrent use may result in additive CNS depression.
Dexbrompheniramine: (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Dexbrompheniramine; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Dexchlorpheniramine: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Dexchlorpheniramine; Dextromethorphan; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Dexmedetomidine: (Moderate) Concurrent use of dexmedetomidine and benzodiazepines may result in additive CNS depression. A reduction in dosage of dexmedetomidine or the benzodiazepine may be required.
Dextroamphetamine: (Moderate) Monitor blood pressure, heart rate, and for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant amphetamine and tricyclic antidepressant use. Adjust doses or use alternative therapy based on clinical response. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for potentiation of cardiovascular effects and serotonin syndrome. Amphetamines may enhance the activity of tricyclic antidepressants causing significant and sustained increases in amphetamine concentrations in the brain.
Dextromethorphan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Dextromethorphan; Bupropion: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Use extreme caution when coadministering bupropion with other drugs that lower the seizure threshold, such as tricyclic antidepressants. Use low initial doses of bupropion and increase the dose gradually. Monitor patients for an increase in tricyclic antidepressant-related adverse reactions and signs and symptoms of serotonin syndrome during concomitant use, particularly during treatment initiation and dosage increases; a dose reduction of the tricyclic antidepressant may be necessary. If serotonin syndrome occurs, consider discontinuation of therapy. The concomitant use of serotonergic drugs increases the risk of serotonin syndrome. Tricyclic antidepressants are CYP2D6 substrates and bupropion is a CYP2D6 inhibitor.
Dextromethorphan; Diphenhydramine; Phenylephrine: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of diphenhydramine and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Dextromethorphan; Guaifenesin: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Dextromethorphan; Guaifenesin; Phenylephrine: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Dextromethorphan; Guaifenesin; Potassium Guaiacolsulfonate: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Dextromethorphan; Guaifenesin; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Dextromethorphan; Quinidine: (Contraindicated) Quinidine administration is associated with QT prolongation and torsade de pointes (TdP). Quinidine inhibits CYP2D6 and has QT-prolonging actions. Quinidine is contraindicated with other drugs that prolong the QT interval and are metabolized by CYP2D6 as the effects on the QT interval may be increased during concurrent use of these agents. Tricyclic antidepressants are associated with a possible risk of QT prolongation, particularly at high dosages or in overdose, and are substrates for CYP2D6. (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Diazepam: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur.
Dicyclomine: (Moderate) Dicyclomine can cause drowsiness, so it should be used cautiously in patients receiving CNS depressants like benzodiazepines. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and dicyclomine use. Concomitant use may result in additive anticholinergic adverse effects.
Dienogest; Estradiol valerate: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Diethylpropion: (Major) Avoid the use of these agents together. Tricyclic antidepressants (TCAs) may potentiate the pressor response to sympathomimetic agents, such as diethylpropion. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience side effects like hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. Patients should be closely monitored if use together is unavoidable.
Diethylstilbestrol, DES: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Difelikefalin: (Moderate) Monitor for dizziness, somnolence, mental status changes, and gait disturbances if concomitant use of difelikefalin with CNS depressants is necessary. Concomitant use may increase the risk for these adverse reactions.
Diltiazem: (Moderate) Diltiazem could theoretically inhibit CYP3A4 metabolism of oxidized benzodiazepines, including chlordiazepoxide.
Dimenhydrinate: (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of dimenhydrinate and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects.
Diphenhydramine: (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of diphenhydramine and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects.
Diphenhydramine; Ibuprofen: (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of diphenhydramine and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects.
Diphenhydramine; Naproxen: (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of diphenhydramine and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects.
Diphenhydramine; Phenylephrine: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of diphenhydramine and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Diphenoxylate; Atropine: (Moderate) Concomitant administration of benzodiazepines with CNS-depressant drugs, such as diphenoxylate/difenoxin, can potentiate the CNS effects of either agent. (Moderate) Concurrent administration can potentiate the CNS and respiratory depressant effects of diphenoxylate/difenoxin and the CNS depressant effects of the tricyclic antidepressant (TCA). Both TCAs and diphenoxylate/difenoxin may cause constipation. Use caution during coadministration. Cases of severe GI reactions including toxic megacolon and adynamic ileus have been rarely reported. In some cases, a dosage reduction of diphenoxylate or difenoxin might be needed to manage any noted side effects. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and atropine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
Disopyramide: (Major) Tricyclic antidepressants (TCAs) share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). This pharmacologic property of the TCAs is of concern in patients with significant cardiac histories or treated with selected cardiac agents. Cases of long QT syndrome and torsade de pointes tachycardia have been described with TCA use, but rarely occur when TCAs are used alone in normal prescribed doses and in the absence of other known risk factors for QT prolongation. Limited data are available regarding the safety of TCAs in combination with other QT-prolonging drugs. One study reported the common occurrence of overlapping prescriptions for 2 or more drugs with potential for QT-prolonging effects; antidepressants were involved in nearly 50% of the cases, but there are little data to document safety of the combined therapies. Class IA antiarrhythmics are associated with QT prolongation and torsades de pointes (TdP). The need to coadminister TCAs with any of these therapies should be done with a careful assessment of risk versus benefit; consider alternative therapy to the TCA. In addition to effects on the EKG, disopyramide has significant anticholinergic effects that are additive to those of the TCAs.
Disulfiram: (Moderate) Disulfiram competes for the binding sites on hepatic cytochrome P-450 with benzodiazepines that undergo oxidative metabolism, including chlordiazepoxide, thereby slowing the metabolism of benzodiazepines and increasing their steady-state plasma concentrations. (Moderate) Limited data suggest that the combination of tricyclic antidepressants with disulfiram can produce transient delirium. In addition, disulfiram may inhibit some of the CYP450 isoenzymes involved in tricyclic antidepressant metabolism, although the clinical significance is unknown.
Donepezil: (Moderate) Use donepezil with caution in combination with tricyclic antidepressants as concurrent use may increase the risk of QT prolongation; the efficacy of donepezil may also be reduced. Case reports indicate that QT prolongation and torsade de pointes (TdP) can occur during donepezil therapy. Tricyclic antidepressants (TCAs) share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). Donepezil inhibits acetylcholinesterase, the enzyme responsible for the degradation of acetylcholine, and improves the availability of acetylcholine. Tricyclic antidepressants with significant anticholinergic activity, such as amitriptyline, imipramine, doxepin, and clomipramine, are more likely to interfere with the therapeutic effect of donepezil than other tricyclics.
Donepezil; Memantine: (Moderate) Use donepezil with caution in combination with tricyclic antidepressants as concurrent use may increase the risk of QT prolongation; the efficacy of donepezil may also be reduced. Case reports indicate that QT prolongation and torsade de pointes (TdP) can occur during donepezil therapy. Tricyclic antidepressants (TCAs) share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). Donepezil inhibits acetylcholinesterase, the enzyme responsible for the degradation of acetylcholine, and improves the availability of acetylcholine. Tricyclic antidepressants with significant anticholinergic activity, such as amitriptyline, imipramine, doxepin, and clomipramine, are more likely to interfere with the therapeutic effect of donepezil than other tricyclics.
Dopamine: (Moderate) Monitor blood pressure and carefully adjust doses during concomitant use of dopamine and tricyclic antidepressants due to the risk for hypertension. Concomitant use of tricyclic antidepressants may potentiate the cardiovascular effects of dopamine.
Doxylamine: (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of doxylamine and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects.
Doxylamine; Pyridoxine: (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of doxylamine and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects.
Dronabinol: (Moderate) Use caution if coadministration of dronabinol with tricyclic antidepressants (e.g., amitriptyline, desipramine) is necessary. Concurrent use of dronabinol, THC with tricyclic antidepressants may result in additive drowsiness, hypertension, tachycardia, and possibly cardiotoxicity. (Moderate) Use caution if the use of benzodiazepines are necessary with dronabinol, and monitor for additive dizziness, confusion, somnolence, and other CNS effects.
Dronedarone: (Contraindicated) Coadministration of dronedarone and tricyclic antidepressants is contraindicated due to the potential for QT prolongation and torsade de pointes (TdP). Tricyclic antidepressants (TCAs) have pharmacologic properties like the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). Dronedarone administration is associated with a dose-related increase in the QTc interval. The increase in QTc is approximately 10 milliseconds at doses of 400 mg twice daily (the FDA-approved dose) and up to 25 milliseconds at doses of 1600 mg twice daily. Although there are no studies examining the effects of dronedarone in patients receiving other QT prolonging drugs, coadministration of such drugs may result in additive QT prolongation.
Droperidol: (Major) Droperidol administration is associated with an established risk for QT prolongation and torsades de pointes. In December 2001, the FDA issued a black box warning regarding the use of droperidol and its association with QT prolongation and potential for cardiac arrhythmias based on post-marketing surveillance data. Risk factors for the development of prolonged QT syndrome may include the use of benzodiazepines. Also, droperidol and benzodiazepines can both cause CNS depression. If used with a benzodiazepine, droperidol should be initiated at a low dose and adjusted upward, with caution, as needed to achieve the desired effect.
Drospirenone; Estetrol: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Drospirenone; Estradiol: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Drospirenone; Ethinyl Estradiol: (Minor) Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines. (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Drospirenone; Ethinyl Estradiol; Levomefolate: (Minor) Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines. (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Duloxetine: (Moderate) Monitor for an increase in tricyclic antidepressant-related adverse reactions and signs and symptoms of serotonin syndrome if coadministration with duloxetine is necessary, particularly during treatment initiation and dosage increases; a dose reduction of the tricyclic antidepressant may be necessary. If serotonin syndrome occurs, consider discontinuation of therapy. The concomitant use of serotonergic drugs increases the risk of serotonin syndrome. Concurrent use may increase exposure of the tricyclic antidepressant. Tricyclic antidepressants are CYP2D6 substrates and duloxetine is a CYP2D6 inhibitor.
Efavirenz: (Moderate) In vivo, efavirenz has been shown to induce hepatic enzymes CYP3A4 and CYP2B6. Patients receiving benzodiazepines that are metabolized by these isoenzymes may experience decreased benzodiazepine serum concentrations if administered concurrently with efavirenz. Efavirenz should be used with caution with oxidized benzodiazepines including chlordiazepoxide. Monitor patients closely for excessive side effects.
Efavirenz; Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) In vivo, efavirenz has been shown to induce hepatic enzymes CYP3A4 and CYP2B6. Patients receiving benzodiazepines that are metabolized by these isoenzymes may experience decreased benzodiazepine serum concentrations if administered concurrently with efavirenz. Efavirenz should be used with caution with oxidized benzodiazepines including chlordiazepoxide. Monitor patients closely for excessive side effects.
Efavirenz; Lamivudine; Tenofovir Disoproxil Fumarate: (Moderate) In vivo, efavirenz has been shown to induce hepatic enzymes CYP3A4 and CYP2B6. Patients receiving benzodiazepines that are metabolized by these isoenzymes may experience decreased benzodiazepine serum concentrations if administered concurrently with efavirenz. Efavirenz should be used with caution with oxidized benzodiazepines including chlordiazepoxide. Monitor patients closely for excessive side effects.
Elagolix; Estradiol; Norethindrone acetate: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Elbasvir; Grazoprevir: (Moderate) Administering chlordiazepoxide with elbasvir; grazoprevir may result in elevated chlordiazepoxide plasma concentrations. Chlordiazepoxide is a substrate of CYP3A; grazoprevir is a weak CYP3A inhibitor. If these drugs are used together, closely monitor for signs of adverse events. (Moderate) Administering perphenazine; amitriptyline with elbasvir; grazoprevir may result in elevated amitriptyline plasma concentrations. Amitriptyline is a substrate of CYP3A; grazoprevir is a weak CYP3A inhibitor. If these drugs are used together, closely monitor for signs of adverse events.
Eliglustat: (Moderate) Coadminister tricyclic antidepressants (TCAs) and eliglustat cautiously and with close monitoring; there may be an increased risk of QT prolongation and/or antidepressant-associated adverse effects. TCAs share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). In addition, coadministration may result in increased concentrations of the antidepressant. If eliglustat and a TCA are used together, consider reducing the dosage of the TCA and titrating to clinical effect. When available, monitoring antidepressant serum concentrations may be beneficial. Eliglustat is a CYP2D6 inhibitor, and tricyclic antidepressants are CYP2D6 substrates.
Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Alafenamide: (Moderate) Close monitoring for antidepressant response and careful dose titrations of the antidepressant therapy is recommended during coadministration of tricyclic antidepressants (TCAs) and cobicistat. Concurrent use may result in elevated TCA plasma concentrations. (Moderate) The plasma concentrations of chlordiazepoxide may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects is recommended during coadministration. Cobicistat is a strong CYP3A4 inhibitor, while chlordiazepoxide is a CYP3A4 substrate.
Elvitegravir; Cobicistat; Emtricitabine; Tenofovir Disoproxil Fumarate: (Moderate) Close monitoring for antidepressant response and careful dose titrations of the antidepressant therapy is recommended during coadministration of tricyclic antidepressants (TCAs) and cobicistat. Concurrent use may result in elevated TCA plasma concentrations. (Moderate) The plasma concentrations of chlordiazepoxide may be elevated when administered concurrently with cobicistat. Clinical monitoring for adverse effects is recommended during coadministration. Cobicistat is a strong CYP3A4 inhibitor, while chlordiazepoxide is a CYP3A4 substrate.
Entacapone: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tricyclic antidepressants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Ephedrine: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to certain sympathomimetic agents, such as ephedrine or ephedra. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat.
Ephedrine; Guaifenesin: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to certain sympathomimetic agents, such as ephedrine or ephedra. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat.
Epinephrine: (Major) Avoid use of epinephrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the vasopressor effects of epinephrine.
Ergotamine; Caffeine: (Minor) Patients taking benzodiazepines for insomnia should not use caffeine-containing products prior to going to bed as these products may antagonize the sedative effects of the benzodiazepine.
Erythromycin: (Minor) The use of erythromycin with tricyclic antidepressants is rarely problematic. Tricyclic antidepressants may prolong the QT interval, particularly in overdose, and erythromycin has also been reported to have this effect in rare circumstances. Erythromycin is sometimes used to stimulate GI motility, for example, in patients with diabetic gastroparesis. In patients requiring erythromycin to enhance GI motility, some tricyclic antidepressants with substantial antimuscarinic properties may counteract erythromycin's effectiveness.
Escitalopram: (Moderate) Use tricyclic antidepressants (TCAs) and escitalopram together with caution as concurrent use may increase the risk of QT prolongation and serotonin syndrome; consider a decreased dosage of the TCA or the avoidance of concomitant SSRI therapy. If serotonin syndrome is suspected, discontinue all serotonergic agents. Escitalopram is a moderate inhibitor of CYP2D6 that has been associated with a risk of QT prolongation and torsade de pointes (TdP). CYP2D6 is responsible for metabolism of many of the TCAs; elevated TCA concentrations may occur in some patients. TCAs share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations).
Esketamine: (Major) Closely monitor patients receiving esketamine and a tricyclic antidepressant for sedation and other CNS depressant effects. Patients who receive a dose of esketamine should not drive or engage in other activities requiring alertness until the next day after a restful sleep. (Major) Closely monitor patients receiving esketamine and benzodiazepines for sedation and other CNS depressant effects. Instruct patients who receive a dose of esketamine not to drive or engage in other activities requiring alertness until the next day after a restful sleep.
Eslicarbazepine: (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions.
Estazolam: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur.
Esterified Estrogens: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Esterified Estrogens; Methyltestosterone: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Estradiol: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Estradiol; Levonorgestrel: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Estradiol; Norethindrone: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Estradiol; Norgestimate: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Estradiol; Progesterone: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Estrogens: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effec ts if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Estropipate: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Eszopiclone: (Moderate) A reduction in the dose of eszopiclone and concomitantly administered CNS depressants, such as tricyclic antidepressants, should be considered to minimize additive sedative effects. 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. Tricyclics with a higher incidence of sedation, such as amitriptyline, imipramine, doxepin, and clomipramine, are more likely to interact with eszopiclone. (Moderate) Concomitant administration of benzodiazepines with eszopiclone can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. The concurrent use of eszopiclone with other anxiolytics, sedatives, and hypnotics at bedtime or in the middle of the night is not recommended. 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. If used together, a reduction in the dose of one or both drugs may be needed.
Ethanol: (Major) Advise patients to avoid alcohol consumption while taking CNS depressants such as tricyclic antidepressants (TCAs). TCAs may exaggerate the CNS depressant response to alcohol, leading to an increase in sedation or psychomotor impairment. In some studies, alcohol has increased the unbound form of the TCA in the blood, which might be related to exaggerated clinical effect. (Major) Advise patients to avoid alcohol consumption while taking CNS depressants. Alcohol consumption may result in additive CNS depression.
Ethinyl Estradiol; Norelgestromin: (Minor) Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines. (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Ethinyl Estradiol; Norethindrone Acetate: (Minor) Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines. (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Ethinyl Estradiol; Norgestrel: (Minor) Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines. (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Ethosuximide: (Moderate) Tricyclic antidepressants, when used concomitantly with anticonvulsants, can increase drowsiness and CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. Monitor patients on anticonvulsants carefully when a TCA is used concurrently.
Ethotoin: (Moderate) Hydantoin anticonvulsants can theoretically increase the clearance of chlordiazepoxide, leading to lower benzodiazepine concentrations. Chlordiazepoxide may also have an unpredictable effect on phenytoin serum concentrations.
Ethynodiol Diacetate; Ethinyl Estradiol: (Minor) Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines. (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Etomidate: (Moderate) Concomitant administration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. (Moderate) General anesthetics like etomidate may produce additive CNS depression when used in patients taking tricyclic antidepressants.
Etonogestrel; Ethinyl Estradiol: (Minor) Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines. (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Everolimus: (Moderate) Monitor for an increase in amitriptyline-related adverse reactions if coadministration with everolimus is necessary; consider reducing the dose of amitriptyline if clinically appropriate. Amitriptyline is a CYP2D6 substrate and everolimus is a CYP2D6 inhibitor; concomitant use may increase plasma concentrations of amitriptyline.
Fedratinib: (Moderate) Monitor for an increase in amitriptyline-related adverse reactions if coadministration with fedratinib is necessary; a dose reduction of amitriptyline may be necessary. Amitriptyline is a CYP2D6 and CYP2C19 substrate and fedratinib is a moderate inhibitor of CYP2D6 and CYP2C19.
Felbamate: (Moderate) Tricyclic antidepressants, when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. Monitor patients on anticonvulsants carefully when a TCA is used concurrently.
Fenfluramine: (Moderate) Monitor for excessive sedation and somnolence during coadministration of fenfluramine and benzodiazepines. Concurrent use may result in additive CNS depression. (Moderate) Use fenfluramine and tricyclic antidepressants with caution due to an increased risk of serotonin syndrome and additive CNS depression. Monitor for excessive sedation, somnolence, and serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Fentanyl: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Fexofenadine; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines.
Flavoxate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and flavoxate use. Concomitant use may result in additive anticholinergic adverse effects.
Fluconazole: (Minor) Fluconazole should be administered together with TCAs with caution. Fluconazole has been associated with QT prolongation and rare cases of torsade de pointes (TdP). TCAs share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). In addition, fluconazole has been reported to increase the effects of amitriptyline, likely via inhibition of the hepatic microsomal CYP2C19 or CYP3A4 isoenzymes. In at least one case, the interaction resulted in an increased incidence of TCA-related side effects, like dizziness and syncope. Monitor for an increased response to amitriptyline if fluconazole is coadministered.
Flumazenil: (Major) Flumazenil competes with benzodiazepines for binding at the GABA/benzodiazepine-receptor complex, the specific binding site of benzodiazepines. Because binding at the receptor is competitive and flumazenil has a much shorter duration of action than do most benzodiazepines, it is possible for the effects of flumazenil to dissipate sooner than the effects of the benzodiazepine. Flumazenil does not affect the pharmacokinetics of the benzodiazepines. Abrupt awakening can cause dysphoria, agitation, and possibly increased adverse effects. If administered to patients who have received a benzodiazepine chronically, abrupt interruption of benzodiazepine agonism by flumazenil can induce benzodiazepine withdrawal including seizures. Flumazenil has minimal effects on benzodiazepine-induced respiratory depression; suitable ventilatory support should be available, especially in treating acute benzodiazepine overdose. Flumazenil does not reverse the actions of barbiturates, opiate agonists, or tricyclic antidepressants. (Major) Particular caution is necessary when using flumazenil in cases of mixed drug overdosage since the toxic effects (such as convulsions and cardiac dysrhythmias) of other drugs taken in overdose (especially tricyclic antidepressants) may emerge with the reversal of the benzodiazepine effect by flumazenil. The reversal of benzodiazepine effects may be associated with the onset of seizures in certain high-risk populations; concurrent cyclic antidepressant poisoning is a risk factor for seizures. Flumazenil is not recommended in cases of serious cyclic antidepressant poisoning, as manifested by motor abnormalities (twitching, rigidity, focal seizure), dysrhythmia (wide QRS, ventricular dysrhythmia, heart block), anticholinergic signs (mydriasis, dry mucosa, hypoperistalsis), and cardiovascular collapse at presentation. In such cases flumazenil should be withheld and the patient should be allowed to remain sedated (with ventilatory and circulatory support as needed) until the signs of antidepressant toxicity have subsided. Treatment with flumazenil has no known benefit to the seriously ill mixed-overdose patient other than reversing sedation and should not be used in cases where seizures (from any cause) are likely.
Fluoxetine: (Moderate) Fluoxetine could theoretically inhibit CYP3A4 metabolism of oxidized benzodiazepines, including chlordiazepoxide. Patients should be monitored for clinical response, and adjust benzodiazepine dosage if needed. (Moderate) Monitor for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant amitriptyline and fluoxetine use. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for serotonin syndrome.
Fluphenazine: (Moderate) When prescribing tricyclic antidepressants (TCAs) to patients already receiving phenothiazine therapy, close monitoring is essential and dose reduction may become necessary to avoid toxicity. Lower doses than usually prescribed for either the phenothiazine or the TCA may be required. TCAs may impair metabolism via the hepatic isoenzyme CYP2D6 at therapeutic doses and may result in increased serum phenothiazine concentrations, leading to side effects. Depending on the specific agent, additive anticholinergic effects may also be seen; clinicians should note that antimuscarinic effects may be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Additive drowsiness or other additive CNS effects may also occur. TCAs may also cause additive cardiac effects (e.g., QT prolongation) in some cases.
Flurazepam: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur.
Fluvoxamine: (Major) Concomitant use of fluvoxamine and tricyclic antidepressants (TCAs) such as amitriptyline may increase the risk of serotonin syndrome, QT prolongation, and torsade de pointes (TdP). Tricyclics share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with high dose therapy (elevated serum concentrations). QT prolongation and TdP have been reported during postmarketing use of fluvoxamine. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. In addition, several isoenzymes have been identified in the metabolism of amitriptyline including CYP2D6 (primary), CYP2C19, CYP1A2, CYP3A4, and CYP2C9. Fluvoxamine is a potent inhibitor of CYP1A2 and 2C19 and a moderate inhibitor of CYP3A4. At least one case report exists of a death thought to be due to impaired clearance of amitriptyline by the SSRI fluoxetine. Patients receiving a TCA should be monitored closely for toxicity if fluvoxamine is added. (Moderate) Fluvoxamine may inhibit the metabolism of benzodiazepines that undergo hepatic oxidation, including chlordiazepoxide.
Food: (Major) Advise patients to avoid cannabis use while taking CNS depressants due to the risk for additive CNS depression and potential for other cognitive adverse reactions.
Fosamprenavir: (Major) CYP3A4 inhibitors, such as protease inhibitors, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. A decrease in the chlordiazepoxide dose may be needed. (Moderate) An increased plasma concentration of amitriptyline is seen when coadministered with fosamprenavir; therapeutic concentration monitoring is recommended when coadministered.
Fosphenytoin: (Moderate) Hydantoin anticonvulsants can theoretically increase the clearance of benzodiazepines metabolized by oxidative metabolism, such as chlordiazepoxide, leading to lower benzodiazepine concentrations. In addition, chlordiazepoxide has been reported to have an unpredictable effect on phenytoin serum concentrations. Conflicting results may have been observed due to saturable phenytoin metabolism and/or other conditions associated with the reported data. Since definitive controlled trial data are lacking, phenytoin concentrations should be monitored more closely when chlordiazepoxide is added or discontinued.
Gabapentin: (Major) Concomitant use of benzodiazepines with gabapentin may cause excessive sedation, somnolence, and respiratory depression. If concurrent use is necessary, initiate gabapentin at the lowest recommended dose and monitor patients for symptoms of respiratory depression and sedation. Educate patients about the risks and symptoms of excessive CNS depression and respiratory depression. (Major) Initiate gabapentin at the lowest recommended dose and monitor patients for symptoms of sedation and somnolence during coadministration of gabapentin and tricyclic antidepressants. Concomitant use of gabapentin with tricyclic antidepressants may cause additive CNS depression. Educate patients about the risks and symptoms of excessive CNS depression.
Galantamine: (Moderate) The therapeutic benefits of galantamine may be diminished when coadministered with drugs known to exhibit anticholinergic properties including tricyclic antidepressants (TCAs). When concurrent use cannot be avoided, monitor the patient for reduced galantamine efficacy, and consider use of secondary TCAs (e.g., desipramine, nortriptyline), which generally have less potent anticholinergic effects than tertiary TCAs (e.g., amitriptyline, clomipramine).
General anesthetics: (Moderate) Concomitant administration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent.
Givosiran: (Major) Avoid concomitant use of givosiran and amitriptyline due to the risk of increased amitriptyline-related adverse reactions. If use is necessary, consider reducing the amitriptyline dose. Amitriptyline is a CYP2D6 substrate. Givosiran may moderately reduce hepatic CYP2D6 enzyme activity because of its pharmacological effects on the hepatic heme biosynthesis pathway.
Glycopyrrolate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and glycopyrrolate use. Concomitant use may result in additive anticholinergic adverse effects.
Glycopyrrolate; Formoterol: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and glycopyrrolate use. Concomitant use may result in additive anticholinergic adverse effects.
Granisetron: (Moderate) Use granisetron with caution in combination with tricyclic antidepressants due to increased risk for QT prolongation, torsade de pointes (TdP), and serotonin syndrome. Discontinue all serotonergic agents and initiate supportive therapy if serotonin syndrome is suspected. Granisetron has been associated with QT prolongation. Tricyclic antidepressants (TCAs) share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations).
Green Tea: (Minor) Patients taking benzodiazepines for insomnia should not use caffeine-containing products, such as green tea, prior to going to bed as these products may antagonize the sedative effects of the benzodiazepine.
Guaifenesin; Hydrocodone: (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 hydrocodone is initiated in a patient taking a benzodiazepine, reduce initial dosage and titrate to clinical response; for hydrocodone extended-release products, initiate hydrocodone at 20% to 30% of 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. Avoid opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants.
Guaifenesin; Phenylephrine: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Guaifenesin; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines.
Guanfacine: (Major) Tricyclic antidepressants (TCAs) can inhibit the hypotensive effects of guanfacine, causing an increase in blood pressure if given concomitantly. Consider alternatives to TCAs in patients established on guanfacine therapy for hypertension when possible; it is not clear the effect the combination may have when used in patients treated with guanfacine for attention-deficit, but other options to TCAs should be considered. Increased dosages of guanfacine may be required to control blood pressure in patients who are receiving TCAs concurrently. In addition, concurrent TCAs may enhance the potential for serious rebound hypertension following guanfacine discontinuation, regardless of the indication for treatment. If guanfacine therapy is withdrawn, guanfacine should be tapered gradually and the patient should be monitored for potential hypertension. (Moderate) Guanfacine has been associated with sedative effects and can potentiate the actions of other CNS depressants including benzodiazepines.
Guanidine: (Moderate) Tricyclic antidepressants (TCAs) may antagonize some of the effects of parasympathomimetics (e.g., cholinesterase inhibitors) due to their anticholinergic activity. However, parasympathomimetics like bethanechol have occasionally been used historically to offset some of the adverse peripheral antimuscarinic (anticholinergic) effects of TCAs, such as dry mouth, constipation, or urinary retention. For years, physostigmine was used as an adjunct to the treatment of TCA overdose; however, its efficacy was limited to addressing anticholinergic effects. Additionally, case reports suggest that harmful effects such as seizures and bradyarrhythmias progressing to asystole, especially in patients with cardiac conduction abnormalities at baseline, are possible. For these reasons, physostigmine is no longer considered a standard of care in the treatment of TCA overdose.
Guselkumab: (Moderate) Clinically relevant drug interactions may occur when guselkumab is administered with sensitive substrates of CYP2D6, such as tricyclic antidepressants (TCA). Monitor TCA concentrations if guselkumab is initiated or discontinued; the TCA dose may need to be adjusted. During chronic inflammation, increased levels of certain cytokines can alter the formation of CYP450 enzymes. Thus, the formation of CYP2D6 could be normalized during guselkumab administration.
Halogenated Anesthetics: (Minor) Tricyclic antidepressants (TCAs) should be used cautiously and with close monitoring with halogenated anesthetics. Halogenated anesthetics can prolong the QT interval. Tricyclic antidepressants (TCAs) share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). In addition, general anesthetics may produce additive CNS depression when used in patients taking tricyclic antidepressants.
Haloperidol: (Moderate) Haloperidol can potentiate the actions of other CNS depressants such as tricyclic antidepressants (TCAs). Caution should be exercised with simultaneous use of these agents due to potential excessive CNS effects. Limited data suggest that haloperidol may inhibit the metabolism of some tricyclic antidepressants, however, the clinical significance of this interaction is uncertain. Haloperidol is an inhibitor of hepatic CYP2D6, and coadministration with many TCAs (which are CYP2D6 substrates) may lead to elevated TCA serum concentrations, potentiating toxicity. Haloperidol has also been associated with a possible risk for QT prolongation and/or torsades de pointes, particularly when excessive doses are used or in overdose. Haloperidol should be used cautiously with other agents that may have this effect (e.g., tricyclic antidepressants). (Moderate) Haloperidol can potentiate the actions of other CNS depressants, such as benzodiazepines, Caution should be exercised with simultaneous use of these agents due to potential excessive CNS effects.
Homatropine; Hydrocodone: (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 hydrocodone is initiated in a patient taking a benzodiazepine, reduce initial dosage and titrate to clinical response; for hydrocodone extended-release products, initiate hydrocodone at 20% to 30% of 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. Avoid opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and homatropine use. Concomitant use may result in additive anticholinergic adverse effects.
Hydantoins: (Moderate) Tricyclic antidepressants (TCA), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. Monitor patients on anticonvulsants carefully when a TCA is used concurrently. In addition, hydantoins may increase TCA metabolism.
Hydrochlorothiazide, HCTZ; Methyldopa: (Moderate) Many references caution against the combined use of tricyclic antidepressants (TCAs) and methyldopa. Although reports exist of loss of blood pressure control when TCAs are added to methyldopa, the interaction is not well documented. Nevertheless, if use of these drugs together is not avoidable, monitor the patient's blood pressure for the desired response. (Moderate) Methyldopa is associated with sedative effects. Methyldopa can potentiate the effects of CNS depressants such as barbiturates, benzodiazepines, opiate agonists, or phenothiazines when administered concomitantly.
Hydrocodone: (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 hydrocodone is initiated in a patient taking a benzodiazepine, reduce initial dosage and titrate to clinical response; for hydrocodone extended-release products, initiate hydrocodone at 20% to 30% of 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. Avoid opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants.
Hydrocodone; Ibuprofen: (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 hydrocodone is initiated in a patient taking a benzodiazepine, reduce initial dosage and titrate to clinical response; for hydrocodone extended-release products, initiate hydrocodone at 20% to 30% of 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. Avoid opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants.
Hydrocodone; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (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 hydrocodone is initiated in a patient taking a benzodiazepine, reduce initial dosage and titrate to clinical response; for hydrocodone extended-release products, initiate hydrocodone at 20% to 30% of 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. Avoid opiate cough medications in patients taking benzodiazepines. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. Avoid prescribing opioid cough medication in patients taking tricyclic antidepressants.
Hydromorphone: (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 hydromorphone is initiated in a patient taking a benzodiazepine, reduce the initial dosage of hydromorphone and titrate to clinical response; for hydromorphone extended-release tablets, use 1/3 to 1/2 of the estimated hydromorphone starting dose. 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. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Hydroxyzine: (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination. (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of hydroxyzine and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects.
Hyoscyamine: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects.
Hyoscyamine; Methenamine; Methylene Blue; Phenyl Salicylate; Sodium Biphosphate: (Contraindicated) Per the manufacturer, treatment initiation with amitriptyline is contraindicated in patients currently receiving intravenous (IV) methylene blue due to an increased risk of serotonin syndrome. If urgent psychiatric treatment is required, interventions other than amitriptyline (e.g., alternative medication, hospitalization) should be considered. Conversely, in patients receiving amitriptyline and requiring urgent treatment with IV methylene blue, amitriptyline should be discontinued immediately and methylene blue therapy initiated only if acceptable alternatives are not available and the potential benefits outweigh the risks. The patient should be monitored for serotonin syndrome for 2 weeks or until 24 hours after the last dose of methylene blue, whichever comes first. Amitriptyline may be re-initiated 24 hours after the last dose of methylene blue. Results from an in vitro study indicate that methylene blue is a potent, reversible inhibitor of the monoamine oxidase type A enzyme (MAO-A). MAO-A is responsible for the metabolism of serotonin. Cases of serotonin syndrome have been reported, primarily following administration of standard infusions of methylene blue (1 to 8 mg/kg) as a visualizing agent, in patients receiving serotonergic agents. It is not known if patients receiving other serotonergic psychiatric agents with IV methylene blue are at a comparable risk or if methylene blue administered by other routes (e.g., orally, local injection) or in doses less than 1 mg/kg IV can produce a similar outcome. Published interaction reports between IV methylene blue and serotonergic psychiatric agents have documented symptoms including lethargy, confusion, delirium, agitation, aggression, obtundation, myoclonus, expressive aphasia, hypertonia, pyrexia, elevated blood pressure, seizures, and/or coma. Signs and symptoms of serotonin syndrome include fever, diaphoresis, shivering, myoclonus, tremor, tachycardia, diarrhea, nausea, headache, incoordination, mental status changes (e.g., agitation, confusion), hyperreflexia, seizures, and coma. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects.
Ibuprofen; Oxycodone: (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. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Ibuprofen; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines.
Idelalisib: (Major) Avoid concomitant use of idelalisib, a strong CYP3A inhibitor, with amitriptyline, a CYP3A substrate, as amitriptyline toxicities may be significantly increased. The AUC of a sensitive CYP3A substrate was increased 5.4-fold when coadministered with idelalisib. (Major) Avoid concomitant use of idelalisib, a strong CYP3A inhibitor, with chlordiazepoxide, a CYP3A substrate, as chlordiazepoxide toxicities may be significantly increased. The AUC of a sensitive CYP3A substrate was increased 5.4-fold when coadministered with idelalisib.
Iloperidone: (Moderate) Drugs that can cause CNS depression, if used concomitantly with iloperidone, may increase both the frequency and the intensity of adverse effects such as drowsiness, sedation, and dizziness. Caution should be used when iloperidone is given in combination with other centrally-acting medications including anxiolytics, sedatives, and hypnotics.
Imatinib: (Major) Imatinib is a potent inhibitor of CYP2D6 and may increase concentrations of other drugs metabolized by this enzyme, such as the tricyclic antidepressants (TCAs). An increase in serum concentrations may increase the risk for TCA-related side effects, such as constipation, dizziness, difficulty with urination, xerostomia, fast or irregular heartbeat, and very rarely, QT prolongation. (Moderate) CYP3A4 inhibitors, such as imatinib, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity.
Indacaterol; Glycopyrrolate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and glycopyrrolate use. Concomitant use may result in additive anticholinergic adverse effects.
Indinavir: (Major) CYP3A4 inhibitors, such as protease inhibitors, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. A decrease in the chlordiazepoxide dose may be needed.
Iobenguane I 123: (Major) Discontinue medications that decrease norepinephrine uptake, such as tricyclic antidepressants, for at least 5 biological half-lives prior to iobenguane I 123 administration. Consider medication tapering or additional supportive therapy as appropriate to minimize the risk for precipitating tricyclic antidepressant withdrawal symptoms. Medications that decrease the uptake of norepinephrine can cause false negative imaging results. Increasing the dose of iobenguane I 123 will not overcome any potential uptake limiting effect of this medication.
Iobenguane I 131: (Major) Discontinue tricyclic antidepressants for at least 5 half-lives before the administration of the dosimetry dose or a therapeutic dose of iobenguane I-131. Do not restart tricyclic antidepressants until at least 7 days after each iobenguane I-131 dose. Drugs that reduce catecholamine uptake or deplete catecholamine stores, such as tricyclic antidepressants, may interfere with iobenguane I-131 uptake into cells and interfere with dosimetry calculations resulting in altered iobenguane I-131 efficacy.
Isavuconazonium: (Moderate) Concomitant use of isavuconazonium with amitriptyline may result in increased serum concentrations of amitriptyline. Amitriptyline 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. (Moderate) Concomitant use of isavuconazonium with chlordiazepoxide may result in increased serum concentrations of chlordiazepoxide. Chlordiazepoxide 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 administration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. (Minor) Tricyclic antidepressants (TCAs) should be used cautiously and with close monitoring with halogenated anesthetics. Halogenated anesthetics can prolong the QT interval. Tricyclic antidepressants (TCAs) share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). In addition, general anesthetics may produce additive CNS depression when used in patients taking tricyclic antidepressants.
Isoniazid, INH: (Major) Due to the risk of serotonin syndrome, concurrent use of amitriptyline and medications with MAO-like activity, such as isoniazid, INH, should be avoided if possible. Isoniazid is chemically related to iproniazid, a drug that was known to possess MAO inhibiting activity. Although isoniazid does not inhibit mitochondrial MAO, it does appear to inhibit plasma MAO and may possess enough MAO inhibiting activity to produce clinical symptoms consistent with serotonergic excess. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. If serotonin syndrome is suspected, amitriptyline and concurrent serotonergic agents should be discontinued.
Isoniazid, INH; Pyrazinamide, PZA; Rifampin: (Major) Due to the risk of serotonin syndrome, concurrent use of amitriptyline and medications with MAO-like activity, such as isoniazid, INH, should be avoided if possible. Isoniazid is chemically related to iproniazid, a drug that was known to possess MAO inhibiting activity. Although isoniazid does not inhibit mitochondrial MAO, it does appear to inhibit plasma MAO and may possess enough MAO inhibiting activity to produce clinical symptoms consistent with serotonergic excess. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. If serotonin syndrome is suspected, amitriptyline and concurrent serotonergic agents should be discontinued. (Moderate) It may be necessary to adjust the dosage of tricyclic antidepressants if given concurrently with rifampin. Rifampin may induce the metabolism of tricyclic antidepressants; coadministration may result in decreased tricyclic antidepressant plasma concentrations. (Moderate) Several hepatic inducers, such as rifampin, can theoretically increase the clearance of benzodiazpines metabolized by oxidative metabolism, leading to lower benzodiazepine concentrations.
Isoniazid, INH; Rifampin: (Major) Due to the risk of serotonin syndrome, concurrent use of amitriptyline and medications with MAO-like activity, such as isoniazid, INH, should be avoided if possible. Isoniazid is chemically related to iproniazid, a drug that was known to possess MAO inhibiting activity. Although isoniazid does not inhibit mitochondrial MAO, it does appear to inhibit plasma MAO and may possess enough MAO inhibiting activity to produce clinical symptoms consistent with serotonergic excess. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. If serotonin syndrome is suspected, amitriptyline and concurrent serotonergic agents should be discontinued. (Moderate) It may be necessary to adjust the dosage of tricyclic antidepressants if given concurrently with rifampin. Rifampin may induce the metabolism of tricyclic antidepressants; coadministration may result in decreased tricyclic antidepressant plasma concentrations. (Moderate) Several hepatic inducers, such as rifampin, can theoretically increase the clearance of benzodiazpines metabolized by oxidative metabolism, leading to lower benzodiazepine concentrations.
Isoproterenol: (Moderate) Monitor hemodynamic parameters during concomitant isoproterenol and tricyclic antidepressant use; dosage adjustments may be necessary. Tricyclic antidepressants may potentiate the effects of isoproterenol.
Itraconazole: (Moderate) CYP3A4 inhibitors, such as itraconazole, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. (Minor) Use itraconazole with caution in combination with tricyclic antidepressants as concurrent use may increase the risk of QT prolongation. Itraconazole has been associated with prolongation of the QT interval. TCAs share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). CYP2C19 and CYP3A4 may be partially involved in the metabolism of TCAs; itraconazole may increase TCA concentrations via inhibition of CYP3A4. In at least one case, an increased incidence of TCA-related side effects, such as dizziness and syncope has occurred in combination with an azole antifungal. In another case, QT-prolongation and torsades de pointes occurred.
Ketamine: (Moderate) Concomitant administration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. (Moderate) General anesthetics, including ketamine, may generally produce additive CNS depression when used in patients taking tricyclic antidepressants (TCAs). Specific interactions between ketamine and TCAs are not certain.
Ketoconazole: (Moderate) Monitor for an increase in chlordiazepoxide-related adverse reactions including sedation and respiratory depression if coadministration with ketoconazole is necessary; adjust the dose of chlordiazepoxide if necessary. Chlordiazepoxide is a CYP3A4 substrate and ketoconazole is a strong CYP3A4 inhibitor.
Labetalol: (Moderate) Monitor for an increase in the incidence and severity of tremor and tricyclic antidepressant (TCA)-related adverse effects during concomitant use of labetalol and TCAs. An increase in the incidence of tremor has been observed during concomitant use of labetalol with tricyclic antidepressants; the mechanism of interaction is unknown. Concomitant use may also increase TCA exposure; TCAs are CYP2D6 substrates and labetalol is a weak CYP2D6 inhibitor.
Lacosamide: (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions.
Lamotrigine: (Moderate) Consider ECG monitoring before and during concomitant use of lamotrigine with other sodium channel blockers known to impair atrioventricular and/or intraventricular cardiac conduction, such as tricyclic antidepressants. Concomitant use of tricyclic antidepressants with lamotrigine may increase the risk of proarrhythmia, especially in patients with clinically important structural or functional heart disease. In vitro testing showed that lamotrigine exhibits class IB antiarrhythmic activity at therapeutically relevant concentrations.
Lansoprazole; Amoxicillin; Clarithromycin: (Moderate) CYP3A4 inhibitors, such as clarithromycin, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity.
Lasmiditan: (Moderate) Monitor for excessive sedation and somnolence during coadministration of lasmiditan and benzodiazepines. Concurrent use may result in additive CNS depression. (Moderate) Monitor for excessive sedation, somnolence, and serotonin syndrome during coadministration of lasmiditan and tricyclic antidepressants. Inform patients taking this combination of the risks and symptoms of excessive CNS depression and serotonin syndrome, particularly after a dose increase or the addition of other serotonergic medications to an existing regimen. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs.
Lemborexant: (Moderate) Monitor for excessive sedation and somnolence during coadministration of lemborexant and tricyclic antidepressants. Dosage adjustments of lemborexant and the tricyclic antidepressant may be necessary when administered together because of potentially additive CNS effects. The risk of next-day impairment, including impaired driving, is increased if lemborexant is taken with other CNS depressants. (Moderate) Monitor for excessive sedation and somnolence during use of lemborexant with benzodiazepines. Dosage adjustments may be necessary when administered together because of potentially additive CNS effects. Use of more than 2 hypnotics should be avoided due to the additive CNS depressant and complex sleep-related behaviors that may occur. While anxiolytic medications may be used concurrently with lemborexant, a reduction in dose of one or both agents may be needed. The risk of next-day impairment, including impaired driving, is increased if lemborexant is taken with other CNS depressants.
Lesinurad: (Moderate) Lesinurad may decrease the systemic exposure and therapeutic efficacy of chlordiazepoxide; monitor for potential reduction in efficacy. Chlordiazepoxide is a CYP3A substrate, and lesinurad is a weak CYP3A inducer.
Lesinurad; Allopurinol: (Moderate) Lesinurad may decrease the systemic exposure and therapeutic efficacy of chlordiazepoxide; monitor for potential reduction in efficacy. Chlordiazepoxide is a CYP3A substrate, and lesinurad is a weak CYP3A inducer.
Letermovir: (Moderate) Closely monitor for chlordiazepoxide-related adverse events if given with letermovir. In patients who are also receiving treatment with cyclosporine, the magnitude of this interaction may be amplified. A clinically relevant increase in the plasma concentration of chlordiazepoxide, a CYP3A4 substrate, may occur during concurrent administration with letermovir, a moderate CYP3A4 inhibitor. The combined effect of letermovir and cyclosporine on CYP3A4 substrates may be similar to a strong CYP3A4 inhibitor.
Levocetirizine: (Moderate) Concurrent use of cetirizine/levocetirizine with benzodiazepines should generally be avoided. Coadministration may increase the risk of CNS depressant-related side effects. If concurrent use is necessary, monitor for excessive sedation and somnolence. (Moderate) Monitor for unusual drowsiness and sedation, urinary retention, and reduced gastric motility during coadministration of cetirizine and tricyclic antidepressants. Concomitant use may result in additive CNS depression or anticholinergic effects.
Levodopa: (Moderate) Monitor blood pressure and for symptoms of dyskinesia during concomitant levodopa and tricyclic antidepressant use. There have been rare reports of adverse reactions, including hypertension and dyskinesia, resulting from the concomitant use.
Levoketoconazole: (Moderate) Monitor for an increase in chlordiazepoxide-related adverse reactions including sedation and respiratory depression if coadministration with ketoconazole is necessary; adjust the dose of chlordiazepoxide if necessary. Chlordiazepoxide is a CYP3A4 substrate and ketoconazole is a strong CYP3A4 inhibitor.
Levomilnacipran: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering serotonin norepinephrine reuptake inhibitors (SNRIs) with other drugs that have serotonergic properties such as tricyclic antidepressants. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. If serotonin syndrome is suspected, the tricyclic antidepressant and concurrent serotonergic agents should be discontinued. (Moderate) Concurrent use of many CNS active drugs, including benzodiazepines, with levomilnacipran has not been evaluated by the manufacturer. Therefore, caution is advisable when combining anxiolytics, sedatives, and hypnotics or other psychoactive medications with levomilnacipran.
Levonorgestrel; Ethinyl Estradiol: (Minor) Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines. (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Levonorgestrel; Ethinyl Estradiol; Ferrous Bisglycinate: (Minor) Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines. (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Levonorgestrel; Ethinyl Estradiol; Ferrous Fumarate: (Minor) Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines. (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Levorphanol: (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 levorphanol is initiated in a patient taking a benzodiazepine, reduce the initial dose of levorphanol by approximately 50% or more. 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. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Reduce the initial dose of levorphanol by approximately 50% or more. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the sero tonergic neurotransmitter system has resulted in serotonin syndrome.
Levothyroxine: (Minor) Thyroid hormones may increase receptor sensitivity and enhance the effects of tricyclic antidepressants. Although this drug combination appears to be safe, be aware of the possibility of exaggerated cardiovascular side effects such as arrhythmias and CNS stimulation.
Levothyroxine; Liothyronine (Porcine): (Minor) Thyroid hormones may increase receptor sensitivity and enhance the effects of tricyclic antidepressants. Although this drug combination appears to be safe, be aware of the possibility of exaggerated cardiovascular side effects such as arrhythmias and CNS stimulation.
Levothyroxine; Liothyronine (Synthetic): (Minor) Thyroid hormones may increase receptor sensitivity and enhance the effects of tricyclic antidepressants. Although this drug combination appears to be safe, be aware of the possibility of exaggerated cardiovascular side effects such as arrhythmias and CNS stimulation.
Lidocaine: (Major) If epinephrine is added to lidocaine for the purpose of infiltration and nerve block or spinal anesthesia, receipt of the product to a patient taking tricyclic antidepressants (TCA) may lead to severe, prolonged hypertension. In general, concurrent use of a local anesthetic solution containing epinephrine and a TCA should be avoided. If coadministration is necessary, careful patient monitoring is essential.
Lidocaine; Epinephrine: (Major) Avoid use of epinephrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the vasopressor effects of epinephrine. (Major) If epinephrine is added to lidocaine for the purpose of infiltration and nerve block or spinal anesthesia, receipt of the product to a patient taking tricyclic antidepressants (TCA) may lead to severe, prolonged hypertension. In general, concurrent use of a local anesthetic solution containing epinephrine and a TCA should be avoided. If coadministration is necessary, careful patient monitoring is essential.
Lidocaine; Prilocaine: (Major) If epinephrine is added to lidocaine for the purpose of infiltration and nerve block or spinal anesthesia, receipt of the product to a patient taking tricyclic antidepressants (TCA) may lead to severe, prolonged hypertension. In general, concurrent use of a local anesthetic solution containing epinephrine and a TCA should be avoided. If coadministration is necessary, careful patient monitoring is essential. (Major) Use prilocaine and tricyclic antidepressants together with caution. If epinephrine is added to prilocaine, severe and prolonged hypertension may occur in a patient taking a TCA. Tricyclic antidepressants can increase the sensitivity to epinephrine by inhibiting epinephrine reuptake or metabolism. If concurrent therapy is necessary, carefully monitor the patient. Administration of a phenothiazine or a butyrophenone may reduce or reverse the pressor effect of epinephrine.
Linezolid: (Contraindicated) Treatment with tricyclic antidepressants (TCAs) is contraindicated in patients currently receiving linezolid due to an increased risk of serotonin syndrome. If urgent psychiatric treatment is required, interventions other than tricyclic antidepressant therapy (e.g., alternative medication, hospitalization) should be considered. Conversely, in patients receiving a TCA and requiring urgent treatment with linezolid, the TCA should be discontinued immediately and linezolid therapy initiated only if acceptable alternatives are not available and the potential benefits of linezolid outweigh the risks. The patient should be monitored for serotonin syndrome for two weeks or until 24 hours after the last dose of linezolid, whichever comes first. The TCA may be re-initiated 24 hours after the last dose of linezolid. Linezolid is an antibiotic that is also a non-selective monoamine oxidase (MAO) inhibitor. Since monoamine oxidase type A deaminates serotonin, administration of a non-selective MAO inhibitor concurrently with a TCA can lead to serious reactions including serotonin syndrome or neuroleptic malignant syndrome-like reactions. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Liothyronine: (Minor) Thyroid hormones may increase receptor sensitivity and enhance the effects of tricyclic antidepressants. Although this drug combination appears to be safe, be aware of the possibility of exaggerated cardiovascular side effects such as arrhythmias and CNS stimulation.
Lisdexamfetamine: (Moderate) Monitor blood pressure, heart rate, and for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant amphetamine and tricyclic antidepressant use. Adjust doses or use alternative therapy based on clinical response. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for potentiation of cardiovascular effects and serotonin syndrome. Amphetamines may enhance the activity of tricyclic antidepressants causing significant and sustained increases in amphetamine concentrations in the brain.
Lithium: (Moderate) Monitor for serotonin syndrome, particularly during lithium initiation, during concomitant tricyclic antidepressant use. If serotonin syndrome occurs, consider discontinuation of lithium and/or the tricyclic antidepressant.
Lofexidine: (Moderate) Monitor for excessive hypotension and sedation during coadministration of lofexidine and benzodiazepines. Lofexidine can potentiate the effects of CNS depressants such as benzodiazepines. (Moderate) Monitor for excessive hypotension and sedation during coadministration of lofexidine and tricyclic antidepressants. Lofexidine can potentiate the effects of CNS depressants. Additionally, monitor ECG during coadministration due to the potential risk for additive QT prolongation. Lofexidine prolongs the QT interval. In addition, there are postmarketing reports of torsade de pointes. Tricyclic antidepressants (TCAs) share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations).
Lonafarnib: (Moderate) Monitor for an increase in chlordiazepoxide-related adverse reactions including sedation and respiratory depression if coadministration with lonafarnib is necessary; adjust the dose of chlordiazepoxide if necessary. Chlordiazepoxide is a CYP3A4 substrate and lonafarnib is a strong CYP3A4 inhibitor.
Lopinavir; Ritonavir: (Major) CYP3A4 inhibitors, such as protease inhibitors, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. A decrease in the chlordiazepoxide dose may be needed. (Moderate) Monitor for an increase in tricyclic antidepressant (TCA)-related adverse reactions if coadministration with ritonavir is necessary; a dose reduction of the TCA may be necessary. Concurrent use may increase exposure of the TCA. TCAs are CYP2D6 substrates and ritonavir is a CYP2D6 inhibitor.
Loratadine; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines.
Lorazepam: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur.
Lorcaserin: (Moderate) Based on the mechanism of action of lorcaserin and the theoretical potential for serotonin syndrome, use with extreme caution in combination with other drugs that may affect the serotonergic neurotransmitter systems, including, tricyclic antidepressants. Patients receiving this combination should be monitored for the emergence of serotonin syndrome or Neuroleptic Malignant Syndrome (NMS) like signs and symptoms.
Loxapine: (Moderate) Use caution when combining tricyclic antidepressants (TCAs) with loxapine, which both exhibit anticholinergic activity and may cause CNS effects. Some TCAs may be more likely to cause side effects than others. Because secondary amines, such as desipramine, are generally less likely than tertiary amines (e.g., amitriptyline) to cause sedation, orthostatic hypotension, and anticholinergic effects, TCAs such as desipramine may be preferred for use with antipsychotics.
Lumacaftor; Ivacaftor: (Moderate) Lumacaftor; ivacaftor may reduce the efficacy of amitriptyline by decreasing its systemic exposure. If used together, monitor patients closely for amitriptyline efficacy; an amitriptyline dosage adjustment may be required to obtain the desired therapeutic effect. Do not exceed recommended maximum doses. Amitriptyline is primarily metabolized by CYP2C19 (and CYP2D6) and is also a substrate of CYP3A4 and CYP2C9. Lumacaftor is a strong CYP3A inducer; in vitro data also suggest that lumacaftor; ivacaftor may induce CYP2C19 and induce and/or inhibit CYP2C9. (Moderate) Lumacaftor; ivacaftor may reduce the efficacy of chlordiazepoxide by decreasing its systemic exposure; a dosage increase of chlordiazepoxide may be necessary during co-administration of lumacaftor; ivacaftor. Do not exceed the maximum recommended dose. Chlordiazepoxide is a CYP3A4 substrate. Lumacaftor is a strong CYP3A inducer.
Lumacaftor; Ivacaftor: (Moderate) Lumacaftor; ivacaftor may reduce the efficacy of amitriptyline by decreasing its systemic exposure. If used together, monitor patients closely for amitriptyline efficacy; an amitriptyline dosage adjustment may be required to obtain the desired therapeutic effect. Do not exceed recommended maximum doses. Amitriptyline is primarily metabolized by CYP2C19 (and CYP2D6) and is also a substrate of CYP3A4 and CYP2C9. Lumacaftor is a strong CYP3A inducer; in vitro data also suggest that lumacaftor; ivacaftor may induce CYP2C19 and induce and/or inhibit CYP2C9.
Lumateperone: (Moderate) Monitor for excessive sedation and somnolence during coadministration of lumateperone and benzodiazepines. Concurrent use may result in additive CNS depression. (Moderate) Monitor for excessive sedation and somnolence during coadministration of lumateperone and tricyclic antidepressants. Concurrent use may result in additive CNS depression.
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 anxiolytics, sedatives, and hypnotics, including benzodiazepines. In one study, co-administration of lurasidone and midazolam increased the Cmax and AUC of midazolam by about 21% and 44%, respectively, compared to midazolam alone; however, dosage adjustment of midazolam based upon pharmacokinetic parameters is not required during concurrent use of lurasidone.
Maprotiline: (Contraindicated) The use of maprotiline with tricyclic antidepressants (TCAs) is not generally recommended, due to the duplicative nature of therapy and the risk for side effects. Additive cardiac effects (e.g., prolonged QT interval), CNS effects, or antimuscarinic effects may occur. Clinicians should note that antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Benzodiazepines or other CNS depressants should be combined cautiously with maprotiline because they could cause additive depressant effects and possible respiratory depression or hypotension. The combination of benzodiazepines and maprotiline is commonly used clinically and is considered to be safe as long as patients are monitored for excessive adverse effects from either agent. Maprotiline may lower the seizure threshold, so when benzodiazepines are used for anticonvulsant effects the patient should be monitored for desired clinical outcomes.
Meclizine: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Melatonin: (Major) Use caution when combining melatonin with the benzodiazepines; when the benzodiazepine is used for sleep, co-use of melatonin should be avoided. Use of more than 1 agent for hypnotic purposes may increase the risk for over-sedation, CNS effects, or sleep-related behaviors. Be alert for unusual changes in moods or behaviors. Use caution when combining melatonin with benzodiazepines for other uses. Patients reporting unusual sleep-related behaviors should likely discontinue melatonin use. In animal studies, melatonin has been shown to increase benzodiazepine binding to receptor sites. In one case report, a benzodiazepine-dependent woman with an 11 year history of insomnia weaned and discontinued her benzodiazepine prescription within a few days without rebound insomnia or apparent benzodiazepine withdrawal when melatonin was given. In another case report, the ingestion of excessive melatonin along with normal doses of chlordiazepoxide and an antidepressant resulted in lethargy and short-term amnestic responses. Both cases suggest additive pharmacodynamic effects. In a clinical trial, there was clear evidence for a transitory pharmacodynamic interaction between melatonin and another hypnotic agent one hour following co-dosing. Concomitant administration resulted in increased impairment of attention, memory and coordination compared to the hypnotic agent alone. (Moderate) Monitor for unusual drowsiness and sedation during coadministration of melatonin and tricyclic antidepressants due to the risk for additive CNS depression.
Meperidine: (Major) Concomitant use of meperidine with tricyclic antidepressants (TCAs) may cause excessive sedation and somnolence. Limit the use of opioid pain medications with TCAs to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome or signs of urinary retention or reduced gastric motility. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. The concomitant use of anticholinergic drugs may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation.
Mepivacaine: (Major) Use mepivacaine and tricyclic antidepressants together with caution. If epinephrine is added to mepivacaine, severe and prolonged hypertension may occur in a patient taking a TCA. Tricyclic antidepressants can increase the sensitivity to epinephrine by inhibiting epinephrine reuptake or metabolism. If concurrent therapy is necessary, carefully monitor the patient. Administration of a phenothiazine or a butyrophenone may reduce or reverse the pressor effect of epinephrine.
Meprobamate: (Moderate) Concomitant administration of benzodiazepines with meprobamate can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. If used together, a reduction in the dose of one or both drugs may be needed. (Moderate) The CNS-depressant effects of meprobamate can be potentiated with concomitant administration of other drugs known to cause CNS depression, including tricyclic antidepressants. If used together, a reduction in the dose of one or both drugs may be needed.
Metaxalone: (Moderate) Coadministration of tricyclic antidepressants (TCAs) with metaxalone may result in additive CNS-depressant effects, such as sedation, and may increase the risk for serotonin syndrome. Use with caution and monitor for the emergence of excessive sedation or serotonin syndrome. If serotonin syndrome is suspected, serotonergic agents should be discontinued and appropriate medical treatment instituted.
Methadone: (Major) Concomitant use of methadone with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of methadone with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. The need to coadminister methadone with drugs known to prolong the QT interval should be done with extreme caution and a careful assessment of treatment risks vs. benefits. Methadone is associated with an increased risk for QT prolongation and torsade de pointes (TdP), especially at higher doses (more than 200 mg/day but averaging approximately 400 mg/day in adult patients). Most cases involve patients being treated for pain with large, multiple daily doses of methadone, although cases have been reported in patients receiving doses commonly used for maintenance treatment of opioid addiction. Tricyclic antidepressants (TCAs) share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose therapy (elevated serum concentrations). Monitor patients closely for cardiac conduction changes. Also monitor patients for the emergence of serotonin syndrome and for signs of urinary retention or reduced gastric motility. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome. The concomitant use of opioids with anticholinergic drugs may increase risk of urinary retention or severe constipation, which may lead to paralytic ileus. (Major) Concurrent 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 dose and minimum duration possible. If methadone is initiated for pain in an opioid-naive patient taking a benzodiazepine, use an initial methadone dose of 2.5 mg PO every 12 hours. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial benzodiazepine dose and titrate to response. In patients treated with methadone for opioid use disorder, cessation of benzodiazepines or other CNS depressants is preferred in most cases. Consider alternatives to benzodiazepines for conditions such as anxiety or insomnia during methadone maintenance treatment. Educate patients about the risks and symptoms of respiratory depression and sedation.
Methamphetamine: (Moderate) Monitor blood pressure, heart rate, and for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant amphetamine and tricyclic antidepressant use. Adjust doses or use alternative therapy based on clinical response. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for potentiation of cardiovascular effects and serotonin syndrome. Amphetamines may enhance the activity of tricyclic antidepressants causing significant and sustained increases in amphetamine concentrations in the brain.
Methenamine; Sodium Acid Phosphate; Methylene Blue; Hyoscyamine: (Contraindicated) Per the manufacturer, treatment initiation with amitriptyline is contraindicated in patients currently receiving intravenous (IV) methylene blue due to an increased risk of serotonin syndrome. If urgent psychiatric treatment is required, interventions other than amitriptyline (e.g., alternative medication, hospitalization) should be considered. Conversely, in patients receiving amitriptyline and requiring urgent treatment with IV methylene blue, amitriptyline should be discontinued immediately and methylene blue therapy initiated only if acceptable alternatives are not available and the potential benefits outweigh the risks. The patient should be monitored for serotonin syndrome for 2 weeks or until 24 hours after the last dose of methylene blue, whichever comes first. Amitriptyline may be re-initiated 24 hours after the last dose of methylene blue. Results from an in vitro study indicate that methylene blue is a potent, reversible inhibitor of the monoamine oxidase type A enzyme (MAO-A). MAO-A is responsible for the metabolism of serotonin. Cases of serotonin syndrome have been reported, primarily following administration of standard infusions of methylene blue (1 to 8 mg/kg) as a visualizing agent, in patients receiving serotonergic agents. It is not known if patients receiving other serotonergic psychiatric agents with IV methylene blue are at a comparable risk or if methylene blue administered by other routes (e.g., orally, local injection) or in doses less than 1 mg/kg IV can produce a similar outcome. Published interaction reports between IV methylene blue and serotonergic psychiatric agents have documented symptoms including lethargy, confusion, delirium, agitation, aggression, obtundation, myoclonus, expressive aphasia, hypertonia, pyrexia, elevated blood pressure, seizures, and/or coma. Signs and symptoms of serotonin syndrome include fever, diaphoresis, shivering, myoclonus, tremor, tachycardia, diarrhea, nausea, headache, incoordination, mental status changes (e.g., agitation, confusion), hyperreflexia, seizures, and coma. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects.
Methocarbamol: (Moderate) Concurrent use of benzodiazepines and other CNS active medications including skeletal muscle relaxants, can potentiate the CNS effects of either agent. Lower doses of one or both agents may be required. The severity of this interaction may be increased when additional CNS depressants are given. (Moderate) Monitor for unusual drowsiness and sedation during coadministration of methocarbamol and tricyclic antidepressants due to the risk for additive CNS depression.
Methohexital: (Moderate) Additive CNS and/or respiratory depression may occur. Additionally, barbiturates may increase the metabolism of chlordiazepoxide. Chlordiazepoxide is a CYP3A4 substrate. Barbiturates are CYP3A4 inducers. (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. In addition, pharmacokinetic interactions may occur. Barbiturates may increase TCA metabolism. Monitor patients during concurrent use.
Methscopolamine: (Moderate) CNS depression can be increased when methscopolamine is combined with other CNS depressants such as any anxiolytics, sedatives, and hypnotics. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and methscopolamine use. Concomitant use may result in additive anticholinergic adverse effects.
Methsuximide: (Moderate) Tricyclic antidepressants, when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. Monitor patients on anticonvulsants carefully when a TCA is used concurrently.
Methyldopa: (Moderate) Many references caution against the combined use of tricyclic antidepressants (TCAs) and methyldopa. Although reports exist of loss of blood pressure control when TCAs are added to methyldopa, the interaction is not well documented. Nevertheless, if use of these drugs together is not avoidable, monitor the patient's blood pressure for the desired response. (Moderate) Methyldopa is associated with sedative effects. Methyldopa can potentiate the effects of CNS depressants such as barbiturates, benzodiazepines, opiate agonists, or phenothiazines when administered concomitantly.
Methylene Blue: (Contraindicated) Per the manufacturer, treatment initiation with amitriptyline is contraindicated in patients currently receiving intravenous (IV) methylene blue due to an increased risk of serotonin syndrome. If urgent psychiatric treatment is required, interventions other than amitriptyline (e.g., alternative medication, hospitalization) should be considered. Conversely, in patients receiving amitriptyline and requiring urgent treatment with IV methylene blue, amitriptyline should be discontinued immediately and methylene blue therapy initiated only if acceptable alternatives are not available and the potential benefits outweigh the risks. The patient should be monitored for serotonin syndrome for 2 weeks or until 24 hours after the last dose of methylene blue, whichever comes first. Amitriptyline may be re-initiated 24 hours after the last dose of methylene blue. Results from an in vitro study indicate that methylene blue is a potent, reversible inhibitor of the monoamine oxidase type A enzyme (MAO-A). MAO-A is responsible for the metabolism of serotonin. Cases of serotonin syndrome have been reported, primarily following administration of standard infusions of methylene blue (1 to 8 mg/kg) as a visualizing agent, in patients receiving serotonergic agents. It is not known if patients receiving other serotonergic psychiatric agents with IV methylene blue are at a comparable risk or if methylene blue administered by other routes (e.g., orally, local injection) or in doses less than 1 mg/kg IV can produce a similar outcome. Published interaction reports between IV methylene blue and serotonergic psychiatric agents have documented symptoms including lethargy, confusion, delirium, agitation, aggression, obtundation, myoclonus, expressive aphasia, hypertonia, pyrexia, elevated blood pressure, seizures, and/or coma. Signs and symptoms of serotonin syndrome include fever, diaphoresis, shivering, myoclonus, tremor, tachycardia, diarrhea, nausea, headache, incoordination, mental status changes (e.g., agitation, confusion), hyperreflexia, seizures, and coma.
Methylphenidate Derivatives: (Moderate) Caution should be observed when coadministering methylphenidate derivatives and tricyclic antidepressants (TCAs). There are postmarketing reports of serotonin syndrome occurring during use of methylphenidate derivatives and other serotonergic medications. Patients receiving this combination should be monitored for the emergence of serotonin syndrome. If serotonin syndrome occurs, all serotonergic agents should be discontinued and appropriate medical management should be implemented.
Metoclopramide: (Minor) Combined use of metoclopramide and other CNS depressants, such as anxiolytics, sedatives, and hypnotics, can increase possible sedation.
Metyrapone: (Moderate) Metyrapone may cause dizziness and/or drowsiness. Other drugs that may also cause drowsiness, such as benzodiazepines, should be used with caution. Additive drowsiness and/or dizziness is possible. (Moderate) Metyrapone may cause dizziness and/or drowsiness. Other drugs that may also cause drowsiness, such as tricyclic antidepressants, should be used with caution. Additive drowsiness and/or dizziness is possible.
Metyrosine: (Moderate) The concomitant administration of metyrosine with benzodiazepines can result in additive sedative effects. (Moderate) The concomitant administration of metyrosine with sedating H1-blockers can result in additive sedative effects.
Midazolam: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur.
Milnacipran: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering serotonin norepinephrine reuptake inhibitors (SNRIs) with other drugs that have serotonergic properties such as tricyclic antidepressants. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. If serotonin syndrome is suspected, the tricyclic antidepressant and concurrent serotonergic agents should be discontinued. (Moderate) Concurrent use of many CNS-active drugs with milnacipran or levomilnacipran has not been evaluated by the manufacturer. Therefore, caution is advisable when combining anxiolytics, sedatives, and hypnotics or other psychoactive medications with these medications.
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 antidepressants. Caution should be exercised when using these agents concurrently. (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 benzodiazepines. Caution should be exercised when using these agents concurrently.
Mirabegron: (Moderate) Mirabegron is a moderate CYP2D6 inhibitor. Exposure of tricyclic antidepressants (TCAs), which are CYP2D6 substrates, may be increased when co-administered with mirabegron. In drug interaction studies, mirabegron increased the Cmax of desipramine by 79% and desipramine AUC by 241% after multiple dose administration of 100 mg mirabegron once daily for 18 days and a single dose of 50 mg desipramine before and concomitantly with mirabegron. It is difficult to predict the magnitude of the interaction with each TCA due to differences in the role of CYP2D6 in the metabolism of these drugs. Therefore, appropriate monitoring and dose adjustment may be necessary.
Mirtazapine: (Moderate) Monitor for unusual drowsiness and sedation during coadministration of benzodiazepines and mirtazapine due to the risk for additive CNS depression. (Moderate) Monitor for unusual drowsiness, sedation, and serotonin syndrome during coadministration due to the risk for additive CNS depression and serotonin syndrome. If serotonin syndrome occurs, consider discontinuation of therapy.
Mitotane: (Major) Use caution if mitotane and amitriptyline are used concomitantly, and monitor for decreased efficacy of amitriptyline and a possible change in dosage requirements. Mitotane is a strong CYP3A4 inducer and amitriptyline is a CYP3A4 substrate; coadministration may result in decreased plasma concentrations of amitriptyline. Additionally, mitotane can cause sedation, lethargy, vertigo, and other CNS adverse reactions; additive CNS effects may occur initially when mitotane is given concurrently with amitriptyline. (Major) Use caution if mitotane and chlordiazepoxide are used concomitantly, and monitor for decreased efficacy of chlordiazepoxide and a possible change in dosage requirements. Mitotane is a strong CYP3A4 inducer and chlordiazepoxide is a CYP3A4 substrate in vitro; coadministration may result in decreased plasma concentrations of chlordiazepoxide. Additionally, mitotane can cause sedation, lethargy, vertigo, and other CNS adverse reactions; additive CNS effects may occur initially when mitotane is given concurrently with chlordiazepoxide.
Molindone: (Moderate) Antipsychotics are associated with anticholinergic effects; therefore, additive effects may be seen during concurrent use of molindone and other drugs having anticholinergic activity such as tricyclic antidepressants. Clinicians should note that antimuscarinic effects may be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Additive drowsiness or other CNS effects may also occur.
Monoamine oxidase inhibitors: (Contraindicated) Due to the risk of serotonin syndrome, monoamine oxidase inhibitors (MAOIs) intended to treat psychiatric disorders are contraindicated for use with tricyclic antidepressants (TCAs) or within 14 days of discontinuing treatment with a TCA. Conversely, TCAs should not be initiated within 14 days of stopping an MAOI. Monitor for serotonin-related side effects during therapy transitions. (Moderate) Monitor for unusual drowsiness and sedation during coadministration of benzodiazepines and monoamine oxidase inhibitors (MAOIs) due to the risk for additive CNS depression.
Morphine: (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 morphine is initiated in a patient taking a benzodiazepine, reduce initial dosages and titrate to clinical response. For extended-release tablets, start with morphine 15 mg PO every 12 hours, and for extended-release capsules, start with 30 mg PO every 24 hours or less. Use an initial morphine; naltrexone dose of 20 mg/0.8 mg PO every 24 hours. 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. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. For extended-release morphine tablets (MS Contin and Morphabond), start with 15 mg every 12 hours. Morphine; naltrexone should be initiated at one-third to one-half the recommended starting dosage. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Morphine; Naltrexone: (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 morphine is initiated in a patient taking a benzodiazepine, reduce initial dosages and titrate to clinical response. For extended-release tablets, start with morphine 15 mg PO every 12 hours, and for extended-release capsules, start with 30 mg PO every 24 hours or less. Use an initial morphine; naltrexone dose of 20 mg/0.8 mg PO every 24 hours. 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. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. For extended-release morphine tablets (MS Contin and Morphabond), start with 15 mg every 12 hours. Morphine; naltrexone should be initiated at one-third to one-half the recommended starting dosage. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Nabilone: (Major) Nabilone should not be taken with benzodiazepines or other sedative/hypnotic agents because these substances can potentiate the central nervous system effects of nabilone. Additive drowsiness and CNS depression can occur. (Moderate) Nabilone should be combined cautiously with tricyclic antidepressants. Tachycardia, hypertension, drowsiness or other CNS effects may occur.
Nalbuphine: (Major) Concomitant use of mixed opiate agonists/antagonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of mixed opiate agonists/antagonists 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 a mixed opiate agonist/antagonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the mixed opiate agonist/antagonist and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking a mixed opiate agonist/antagonist, 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. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Naproxen; Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines.
Nefazodone: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering tricyclic antidepressants (TCAs) with other drugs that have serotonergic properties such as nefazodone. Both nefazodone and TCAs inhibit the central reuptake of serotonin. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. Cases of serotonin syndrome or serotonin-related adverse events have been observed during concurrent use of serotonergic antidepressants and nefazodone. If serotonin syndrome is suspected, tricyclic antidepressants and concurrent serotonergic agents should be discontinued.
Nelfinavir: (Major) CYP3A4 inhibitors, such as protease inhibitors, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. A decrease in the chlordiazepoxide dose may be needed.
Neostigmine: (Moderate) Tricyclic antidepressants (TCAs) may antagonize some of the effects of parasympathomimetics (e.g., cholinesterase inhibitors) due to their anticholinergic activity. However, parasympathomimetics like bethanechol have occasionally been used historically to offset some of the adverse peripheral antimuscarinic (anticholinergic) effects of TCAs, such as dry mouth, constipation or urinary retention. For years, physostigmine was used as an adjunct to the treatment of TCA overdose; however, its efficacy was limited to addressing anticholinergic effects. Additionally, case reports suggest that harmful effects such as seizures and bradyarrhythmias progressing to asystole, especially in patients with cardiac conduction abnormalities at baseline, are possible. For these reasons, physostigmine is no longer considered a standard of care in the treatment of TCA overdose.
Neostigmine; Glycopyrrolate: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and glycopyrrolate use. Concomitant use may result in additive anticholinergic adverse effects. (Moderate) Tricyclic antidepressants (TCAs) may antagonize some of the effects of parasympathomimetics (e.g., cholinesterase inhibitors) due to their anticholinergic activity. However, parasympathomimetics like bethanechol have occasionally been used historically to offset some of the adverse peripheral antimuscarinic (anticholinergic) effects of TCAs, such as dry mouth, constipation or urinary retention. For years, physostigmine was used as an adjunct to the treatment of TCA overdose; however, its efficacy was limited to addressing anticholinergic effects. Additionally, case reports suggest that harmful effects such as seizures and bradyarrhythmias progressing to asystole, especially in patients with cardiac conduction abnormalities at baseline, are possible. For these reasons, physostigmine is no longer considered a standard of care in the treatment of TCA overdose.
Nicardipine: (Moderate) CYP3A4 inhibitors, such as nicardipine, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. Monitor patients closely who receive concurrent therapy.
Niraparib; Abiraterone: (Moderate) Monitor for an increase in amitriptyline-related adverse reactions if coadministration with abiraterone is necessary; a dose reduction of amitriptyline may be necessary. Amitriptyline is a CYP2D6 substrate and abiraterone is a moderate CYP2D6 inhibitor. Patients who are stable on a given dose of amitriptyline may become abruptly toxic when given abiraterone is concomitant therapy.
Nirmatrelvir; Ritonavir: (Major) Consider withholding chlordiazepoxide, if clinically appropriate, during receipt of ritonavir-boosted nirmatrelvir. If this is not feasible, consider using an alternative COVID-19 therapy or reducing the chlordiazepoxide dose. However, do not stop chlordiazepoxide abruptly or rapidly reduce the dose as this may precipitate an acute withdrawal reaction, especially in patients who have been receiving high doses over an extended period. Coadministration may increase chlordiazepoxide exposure resulting in increased toxicity and excessive sedation. Chlordiazepoxide is a CYP3A substrate and nirmatrelvir is a CYP3A inhibitor. (Major) CYP3A4 inhibitors, such as protease inhibitors, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. A decrease in the chlordiazepoxide dose may be needed. (Moderate) Monitor for an increase in tricyclic antidepressant (TCA)-related adverse reactions if coadministration with ritonavir is necessary; a dose reduction of the TCA may be necessary. Concurrent use may increase exposure of the TCA. TCAs are CYP2D6 substrates and ritonavir is a CYP2D6 inhibitor.
Nitroglycerin: (Minor) Nitroglycerin can cause hypotension. This action may be additive with other agents that can cause hypotension such as antidepressants. Patients should be monitored more closely for hypotension if nitroglycerin is used concurrently with antidepressants. (Minor) Nitroglycerin can cause hypotension. This action may be additive with other agents that can cause hypotension such as benzodiazepines. Patients should be monitored more closely for hypotension if nitroglycerin is used concurrently with benzodiazepines.
Non-Ionic Contrast Media: (Major) Use of medications that lower the seizure threshold should be carefully evaluated when considering the use of intrathecal radiopaque contrast agents. Tricyclic antidepressants should be discontinued at least 48 hours before myelography and should not be resumed for at least 24 hours postprocedure.
Norepinephrine: (Major) Avoid coadministration of norepinephrine with tricyclic antidepressants as concurrent use can cause severe, prolonged hypertension. If administration of norepinephrine cannot be avoided in these patients, monitor for hypertension.
Norethindrone Acetate; Ethinyl Estradiol; Ferrous fumarate: (Minor) Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines. (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Norethindrone; Ethinyl Estradiol: (Minor) Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines. (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Norethindrone; Ethinyl Estradiol; Ferrous fumarate: (Minor) Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines. (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Norgestimate; Ethinyl Estradiol: (Minor) Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines. (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Olanzapine: (Major) Concurrent use of intramuscular olanzapine and parenteral benzodiazepines is not recommended due to the potential for adverse effects from the combination, including excess sedation and/or cardiopulmonary depression. Although oral formulations of olanzapine and benzodiazepines may be used together, additive effects on respiratory depression and/or CNS depression are possible. Drugs that can cause CNS depression, if used concomitantly with olanzapine, can increase both the frequency and severity of adverse effects such as drowsiness, sedation, dizziness, and orthostatic hypotension. (Moderate) Olanzapine or tricyclic antidepressants, at elevated serum concentrations, may prolong the QTc interval. In addition, anticholinergic effects and sedation may be seen when tricyclic antidepressants are used with olanzapine.
Olanzapine; Fluoxetine: (Major) Concurrent use of intramuscular olanzapine and parenteral benzodiazepines is not recommended due to the potential for adverse effects from the combination, including excess sedation and/or cardiopulmonary depression. Although oral formulations of olanzapine and benzodiazepines may be used together, additive effects on respiratory depression and/or CNS depression are possible. Drugs that can cause CNS depression, if used concomitantly with olanzapine, can increase both the frequency and severity of adverse effects such as drowsiness, sedation, dizziness, and orthostatic hypotension. (Moderate) Fluoxetine could theoretically inhibit CYP3A4 metabolism of oxidized benzodiazepines, including chlordiazepoxide. Patients should be monitored for clinical response, and adjust benzodiazepine dosage if needed. (Moderate) Monitor for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant amitriptyline and fluoxetine use. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for serotonin syndrome. (Moderate) Olanzapine or tricyclic antidepressants, at elevated serum concentrations, may prolong the QTc interval. In addition, anticholinergic effects and sedation may be seen when tricyclic antidepressants are used with olanzapine.
Olanzapine; Samidorphan: (Major) Concurrent use of intramuscular olanzapine and parenteral benzodiazepines is not recommended due to the potential for adverse effects from the combination, including excess sedation and/or cardiopulmonary depression. Although oral formulations of olanzapine and benzodiazepines may be used together, additive effects on respiratory depression and/or CNS depression are possible. Drugs that can cause CNS depression, if used concomitantly with olanzapine, can increase both the frequency and severity of adverse effects such as drowsiness, sedation, dizziness, and orthostatic hypotension. (Moderate) Olanzapine or tricyclic antidepressants, at elevated serum concentrations, may prolong the QTc interval. In addition, anticholinergic effects and sedation may be seen when tricyclic antidepressants are used with olanzapine.
Oliceridine: (Major) Concomitant use of oliceridine with chlordiazepoxide may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opioid pain medication with chlordiazepoxide to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. (Major) Concomitant use of oliceridine with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of oliceridine with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Omeprazole: (Moderate) Omeprazole inhibits CYP2C19. There have been some case reports describing an interaction between omeprazole and benzodiazepines metabolized via the cytochrome P450 system, such as chlordiazepoxide. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole.
Omeprazole; Amoxicillin; Rifabutin: (Moderate) Omeprazole inhibits CYP2C19. There have been some case reports describing an interaction between omeprazole and benzodiazepines metabolized via the cytochrome P450 system, such as chlordiazepoxide. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole. (Moderate) Rifabutin is a hepatic inducer and can theoretically increase the clearance of benzodiazpines metabolized by oxidative metabolism, including chlordiazepoxide, leading to lower benzodiazepine concentrations.
Omeprazole; Sodium Bicarbonate: (Moderate) Omeprazole inhibits CYP2C19. There have been some case reports describing an interaction between omeprazole and benzodiazepines metabolized via the cytochrome P450 system, such as chlordiazepoxide. Patients should be monitored to determine if it is necessary to adjust the dosage of the benzodiazepine when taken concomitantly with omeprazole.
Opicapone: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tricyclic antidepressants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Oritavancin: (Moderate) Chlordiazepoxide is metabolized by CYP3A4; oritavancin is a weak CYP3A4 inducer. Plasma concentrations and efficacy of chlordiazepoxide may be reduced if these drugs are administered concurrently. (Moderate) Coadministration of oritavancin and amitriptyline may result in increases or decreases in amitriptyline exposure and may increase side effects or decrease efficacy of amitriptyline. Amitriptyline is metabolized by CYP3A4, CYP2D6, CYP2C19, and CYP2C9. Oritavancin weakly induces CYP3A4 and CYP2D6, while weakly inhibiting CYP2C9 and CYP2C19. If these drugs are administered concurrently, monitor the patient for signs of toxicity or lack of efficacy.
Orphenadrine: (Moderate) Orphenadrine should be combined cautiously with tricyclic antidepressants due to the potential for additive anticholinergic and CNS depressant effects. Antimuscarinic effects might be seen on GI smooth muscle, bladder function, the eye, and temperature regulation. Consider an alternative skeletal muscle relaxant.
Osilodrostat: (Moderate) Monitor for an increase in amitriptyline-related adverse reactions if coadministration with osilodrostat is necessary; a dose reduction of amitriptyline may be necessary. Concurrent use may increase exposure of amitriptyline. Additionally, consider more frequent ECG monitoring due to the risk of additive QT prolongation. Amitriptyline is a CYP2D6 substrate that may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). Osilodrostat is a CYP2D6 inhibitor that is associated with dose-dependent QT prolongation.
Oxazepam: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur.
Oxcarbazepine: (Moderate) Use amitriptyline with caution in patients with a history of seizures; amitriptyline may lower the seizure threshold and thus potentially interfere with the ability of antiepileptics to control seizures. In addition, concomitant use of amitriptyline and oxcarbazepine may result in additive CNS depression. Oxcarbazepine, a CYP2C19 inhibitor, can increase plasma concentrations of amitriptyline, a substrate of CYP2C19.
Oxybutynin: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and oxybutynin use. Concomitant use may result in additive anticholinergic adverse effects.
Oxycodone: (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. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Oxymorphone: (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 oxymorphone is initiated in a patient taking a benzodiazepine, use an initial dose of oxymorphone at 1/3 to 1/2 the usual dosage and titrate to clinical response. If the extended-release oxymorphone tablets are used concurrently with a CNS depressant, use an initial dosage of 5 mg PO every 12 hours. 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. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation, somnolence, and increased risk of serotonin syndrome. The anticholinergic properties of tricyclic antidepressants may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Reduce the initial oxymorphone dosage by 1/3 to 1/2. Educate patients about the risks and symptoms of excessive CNS depression and serotonin syndrome. Monitor for signs of urinary retention and reduced gastric motility.
Ozanimod: (Contraindicated) Do not use tricyclic antidepressants (TCAs) in patients taking MAOIs or within 14 days of stopping them. An active metabolite of ozanimod inhibits MAO-B, and interactions with TCAs may manifest as serotonin syndrome, hypertensive crisis, QT prolongation or other serious side effects. Hyperpyretic crises, severe convulsions, and deaths have occurred in patients receiving TCAs and MAO inhibiting drugs simultaneously. Consider an alternative to the TCA. Ozanimod is a monoamine oxidase inhibitor that may result in a transient decrease in heart rate and atrioventricular conduction delays. Ozanimod has not been studied in patients taking concurrent QT prolonging drugs; however, QT prolonging drugs have been associated with TdP in patients with bradycardia. TCAs are serotonergic drugs that share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations).
Paliperidone: (Moderate) Concurrent use of paliperidone and tricyclic antidepressants should be avoided if possible. Paliperidone has a risk for QT prolongation and torsade de pointes, and tricyclic antidepressants, primarily at elevated serum concentrations, may produce clinically significant prolongation of the QTc interval. In addition, there is a potential for other pharmacodynamic interactions, such as augmentation of CNS impairment. (Moderate) Drugs that can cause CNS depression, such as benzodiazepines, can increase both the frequency and the intensity of adverse effects such as drowsiness, sedation, and dizziness when coadministered with paliperidone. Monitor for signs and symptoms of CNS depression and advise patients to avoid driving or engaging in other activities requiring mental alertness until they know how this combination affects them.
Panobinostat: (Major) The co-administration of panobinostat with tricyclic antidepressants such as amitriptyline is not recommended; QT prolongation has been reported with both of these agents. If concomitant use cannot be avoided, closely monitor patients for signs and symptoms of tricyclic antidepressant toxicity, including QT prolongation and cardiac arrhythmias. Panobinostat is a CYP2D6 inhibitor and tricyclic antidepressants are CYP2D6 substrates. When a single-dose of a CYP2D6-sensitive substrate was administered after 3 doses of panobinostat (20 mg given on days 3, 5, and 8), the CYP2D6 substrate Cmax increased by 20% to 200% and the AUC value increased by 20% to 130% in 14 patients with advanced cancer; exposure was highly variable (coefficient of variance > 150%).
Papaverine: (Moderate) Concurrent use of papaverine with potent CNS depressants such as benzodiazepines could lead to enhanced sedation.
Paroxetine: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering selective serotonin reuptake inhibitors (SSRIs) with other drugs that have serotonergic properties such as tricyclic antidepressants. Additionally, monitor for an increase in amitriptyline-related adverse reactions if coadministration with paroxetine is necessary; a dose reduction of amitriptyline may be necessary. Concurrent use may increase the plasma concentrations of amitriptyline. Amitriptyline is a CYP2D6 substrate and paroxetine is a CYP2D6 inhibitor. Paroxetine and amitriptyline both exhibit significant anticholinergic effects that may be additive during concurrent use.
Pazopanib: (Minor) Coadministration of pazopanib and other drugs that prolong the QT interval, such as tricyclic antidepressants is not advised; pazopanib has been reported to prolong the QT interval. If pazopanib and the other drug must be continued, closely monitor the patient for QT interval prolongation. In addition, pazopanib is a weak inhibitor of CYP3A4. Amitriptyline, clomipramine and imipramine are CYP3A4 substrates. Coadministration of pazopanib may cause an increase in systemic concentrations of the tricyclic antidepressant. Use caution when administering these drugs concomitantly.
Peginterferon Alfa-2b: (Moderate) Monitor for adverse effects associated with increased exposure to amitriptyline if peginterferon alfa-2b is coadministered. Peginterferon alfa-2b is a CYP2D6 inhibitor, while amitriptyline is a CYP2D6 substrate.
Pentazocine: (Major) Concomitant use of mixed opiate agonists/antagonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of mixed opiate agonists/antagonists 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 a mixed opiate agonist/antagonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the mixed opiate agonist/antagonist and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking a mixed opiate agonist/antagonist, 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) Pain medications such as pentazocine should be combined cautiously with tricyclic antidepressants due to the possibility of additive CNS depression, respiratory depression, hypotension, or decreased intestinal motility. Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering tricyclic antidepressants with other drugs that have serotonergic properties such as pentazocine. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. If serotonin syndrome is suspected, tricyclic antidepressant and concurrent serotonergic agents should be discontinued.
Pentazocine; Naloxone: (Major) Concomitant use of mixed opiate agonists/antagonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of mixed opiate agonists/antagonists 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 a mixed opiate agonist/antagonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the mixed opiate agonist/antagonist and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking a mixed opiate agonist/antagonist, 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) Pain medications such as pentazocine should be combined cautiously with tricyclic antidepressants due to the possibility of additive CNS depression, respiratory depression, hypotension, or decreased intestinal motility. Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering tricyclic antidepressants with other drugs that have serotonergic properties such as pentazocine. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. If serotonin syndrome is suspected, tricyclic antidepressant and concurrent serotonergic agents should be discontinued.
Pentobarbital: (Moderate) Additive CNS and/or respiratory depression may occur. Additionally, barbiturates may increase the metabolism of chlordiazepoxide. Chlordiazepoxide is a CYP3A4 substrate. Barbiturates are CYP3A4 inducers. (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. In addition, pharmacokinetic interactions may occur. Barbiturates may increase TCA metabolism. Monitor patients during concurrent use.
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 amitriptyline. In addition, tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, may also lower the seizure threshold. Monitor patients for changes in efficacy of perampanel. (Moderate) Patients taking benzodiazepines with perampanel may experience increased CNS depression. Monitor patients for adverse effects; dose adjustment of either drug may be necessary. Use of midazolam in healthy subjects who received perampanel 6 mg once daily for 20 days decreased the AUC and Cmax of midazolam by 13% and 15%, respectively, possibly due to weak induction of CYP3A4 by perampanel; the specific clinical significance of this interaction is unknown.
Perphenazine: (Moderate) During coadministration of tricyclic antidepressants (TCAs) and perphenazine, close monitoring is essential and dose reduction may become necessary to avoid toxicity. Phenothiazines have been reported to prolong the QT interval. Because tricyclic antidepressants are associated with a possible risk for QT prolongation and torsade de pointes when given in excessive doses or overdosage, concurrent use with phenothiazines should be approached with caution. Additive anticholinergic effects or sedation may also occur.
Perphenazine; Amitriptyline: (Moderate) During coadministration of tricyclic antidepressants (TCAs) and perphenazine, close monitoring is essential and dose reduction may become necessary to avoid toxicity. Phenothiazines have been reported to prolong the QT interval. Because tricyclic antidepressants are associated with a possible risk for QT prolongation and torsade de pointes when given in excessive doses or overdosage, concurrent use with phenothiazines should be approached with caution. Additive anticholinergic effects or sedation may also occur.
Phendimetrazine: (Major) Avoid use of tricyclic antidepressants with phendimetrazine whenever possible. Tricyclic antidepressants (TCAs) may potentiate the pressor response to sympathomimetic agents, such as phendimetrazine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience side effects like hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. Patients should be closely monitored if use together is unavoidable.
Phenobarbital: (Moderate) Additive CNS and/or respiratory depression may occur. Additionally, barbiturates may increase the metabolism of chlordiazepoxide. Chlordiazepoxide is a CYP3A4 substrate. Barbiturates are CYP3A4 inducers. (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. In addition, pharmacokinetic interactions may occur. Barbiturates may increase TCA metabolism. Monitor patients during concurrent use.
Phenobarbital; Hyoscyamine; Atropine; Scopolamine: (Moderate) Additive CNS and/or respiratory depression may occur. Additionally, barbiturates may increase the metabolism of chlordiazepoxide. Chlordiazepoxide is a CYP3A4 substrate. Barbiturates are CYP3A4 inducers. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and hyoscyamine use. Concomitant use may result in additive anticholinergic adverse effects. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and atropine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and scopolamine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects. (Moderate) Scopolamine may cause dizziness and drowsiness. Concurrent use of scopolamine and CNS depressants can adversely increase the risk of CNS depression. (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. In addition, pharmacokinetic interactions may occur. Barbiturates may increase TCA metabolism. Monitor patients during concurrent use.
Phenothiazines: (Major) Limit dosage and duration of benzodiazepines during concomitant phenothiazine use and monitor for unusual drowsiness and sedation due to the risk for additive CNS depression.
Phentermine: (Moderate) Monitor blood pressure and heart rate during concomitant phentermine and tricyclic antidepressant use. Adjust doses or use alternative therapy based on clinical response. Concomitant use increases the risk for potentiation of cardiovascular effects. Amphetamines may enhance the activity of tricyclic antidepressants causing significant and sustained increases in amphetamine concentrations in the brain.
Phentermine; Topiramate: (Moderate) Monitor blood pressure and heart rate during concomitant phentermine and tricyclic antidepressant use. Adjust doses or use alternative therapy based on clinical response. Concomitant use increases the risk for potentiation of cardiovascular effects. Amphetamines may enhance the activity of tricyclic antidepressants causing significant and sustained increases in amphetamine concentrations in the brain. (Moderate) Monitor for unusual drowsiness or excess sedation and for increased amitriptyline-related adverse events during concomitant topiramate use. Concomitant use resulted in an increase in amitriptyline exposure by 12% and may increase the risk for additive CNS depression. (Moderate) Topiramate has the potential to cause CNS depression as well as other cognitive and/or neuropsychiatric adverse reactions. The CNS depressant effects of topiramate can be potentiated pharmacodynamically by concurrent use of CNS depressant agents such as the benzodiazepines.
Phenylephrine: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Phenytoin: (Moderate) Phenytoin is a hepatic inducer and can theoretically increase the clearance of chlordiazepoxide oxidative metabolism, leading to lower benzodiazepine concentrations. In addition, chlordiazepoxide has been reported to have an unpredictable effect on phenytoin serum concentrations (e.g., to increase, decrease, or cause no change in phenytoin serum concentrations). Conflicting results may have been observed due to saturable phenytoin metabolism and/or other conditions associated with the reported data. Since definitive controlled trial data are lacking, phenytoin concentrations should be monitored more closely when chlordiazepoxide is added or discontinued.
Physostigmine: (Moderate) Tricyclic antidepressants may antagonize some of the effects of cholinesterase inhibitors due to their anticholinergic activity. It may be helpful to choose an alternative antidepressant with lower propensity for anticholinergic activity.
Pilocarpine: (Moderate) Tricyclic antidepressants (TCAs) may antagonize some of the effects of parasympathomimetics (e.g., cholinesterase inhibitors) due to their anticholinergic activity. However, parasympathomimetics like bethanechol have occasionally been used historically to offset some of the adverse peripheral antimuscarinic (anticholinergic) effects of TCAs, such as dry mouth, constipation, or urinary retention. For years, physostigmine was used as an adjunct to the treatment of TCA overdose; however, its efficacy was limited to addressing anticholinergic effects. Additionally, case reports suggest that harmful effects such as seizures and bradyarrhythmias progressing to asystole, especially in patients with cardiac conduction abnormalities at baseline, are possible. For these reasons, physostigmine is no longer considered a standard of care in the treatment of TCA overdose.
Pimozide: (Contraindicated) Pimozide is associated with a well-established risk of QT prolongation and torsade de pointes (TdP). Because of the potential for TdP, use of tricyclic antidepressants with pimozide is contraindicated. (Moderate) Due to the effects of pimozide on cognition, it should be used cautiously with other CNS depressants including benzodiazepines.
Pitolisant: (Major) Avoid coadministration of pitolisant with tricyclic antidepressants (TCAs) as the effect of pitolisant may be decreased; concurrent use may also increase the risk of QT prolongation. Pitolisant increases histamine concentrations in the brain; therefore, H1-receptor antagonists like TCAs, may reduce pitolisant efficacy. Pitolisant prolongs the QT interval. TCAs share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations).
Porfimer: (Major) Avoid coadministration of porfimer with tricyclic antidepressants due to the risk of increased photosensitivity. All patients treated with porfimer will be photosensitive. Concomitant use of other photosensitizing agents like tricyclic antidepressants may increase the risk of a photosensitivity reaction.
Posaconazole: (Moderate) Posaconazole inhibits CYP3A4 and may increase serum concentrations of benzodiazepines metabolized by this enzyme, including chlordiazepoxide. (Minor) Posaconazole is associated with QT prolongation. Tricyclic antidepressants (TCAs) share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). In addition, posaconazole inhibits CYP3A4, CYP2C19, and CYP3A4 may be partially involved in the metabolism of TCAs. Fluconazole has been reported to increase the effects of amitriptyline, perhaps through inhibition of the hepatic microsomal CYP2C19 or CYP3A4 isoenzymes. In at least one case, the interaction resulted in an increased incidence of TCA-related side effects, such as dizziness and syncope. In another case, QT-prolongation and torsades de pointes occurred. Monitor for an increased response to amitriptyline if fluconazole, posaconazole, or voriconazole are coadministered.
Pralidoxime: (Moderate) Tricyclic antidepressants (TCAs) may antagonize some of the effects of parasympathomimetics (e.g., cholinesterase inhibitors) due to their anticholinergic activity. However, parasympathomimetics like bethanechol have occasionally been used historically to offset some of the adverse peripheral antimuscarinic (anticholinergic) effects of TCAs, such as dry mouth, constipation, or urinary retention. For years, physostigmine was used as an adjunct to the treatment of TCA overdose; however, its efficacy was limited to addressing anticholinergic effects. Additionally, case reports suggest that harmful effects such as seizures and bradyarrhythmias progressing to asystole, especially in patients with cardiac conduction abnormalities at baseline, are possible. For these reasons, physostigmine is no longer considered a standard of care in the treatment of TCA overdose.
Pramipexole: (Major) Concomitant administration of benzodiazepines with CNS-depressant drugs, including pramipexole, can potentiate the CNS effects. (Moderate) Pramipexole may cause additive drowsiness when combined with tricyclic antidepressants.
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 tricyclic antidepressants, should be used with caution, if at all, with pramlintide until more data are available from the manufacturer. Monitor blood glucose.
Prasterone, Dehydroepiandrosterone, DHEA (Dietary Supplements): (Major) Prasterone, dehydroepiandrosterone, DHEA may inhibit the metabolism of benzodiazepines (e.g., alprazolam, estazolam, midazolam) which undergo CYP3A4-mediated metabolism. In one study of elderly volunteers, half of the patients received DHEA 200 mg/day PO for 2 weeks, followed by a single dose of triazolam 0.25 mg. Triazolam clearance was reduced by close to 30% in the DHEA-pretreated patients vs. the control group; however, the effect of DHEA on CYP3A4 metabolism appeared to vary widely among subjects. While more study is needed, benzodiazepine-induced CNS sedation and other adverse effects might be increased in some individuals if DHEA is co-administered.
Prasterone, Dehydroepiandrosterone, DHEA (FDA-approved): (Major) Prasterone, dehydroepiandrosterone, DHEA may inhibit the metabolism of benzodiazepines (e.g., alprazolam, estazolam, midazolam) which undergo CYP3A4-mediated metabolism. In one study of elderly volunteers, half of the patients received DHEA 200 mg/day PO for 2 weeks, followed by a single dose of triazolam 0.25 mg. Triazolam clearance was reduced by close to 30% in the DHEA-pretreated patients vs. the control group; however, the effect of DHEA on CYP3A4 metabolism appeared to vary widely among subjects. While more study is needed, benzodiazepine-induced CNS sedation and other adverse effects might be increased in some individuals if DHEA is co-administered.
Pregabalin: (Major) Concomitant use of benzodiazepines with pregabalin may cause excessive sedation, somnolence, and respiratory depression. If concurrent use is necessary, initiate pregabalin at the lowest recommended dose and monitor patients for symptoms of respiratory depression and sedation. Educate patients about the risks and symptoms of excessive CNS depression and respiratory depression. (Major) Initiate pregabalin at the lowest recommended dose and monitor patients for symptoms of sedation and somnolence during coadministration of pregabalin and tricyclic antidepressants. Concomitant use of pregabalin with tricyclic antidepressants may cause additive CNS depression. Educate patients about the risks and symptoms of excessive CNS depression.
Prilocaine: (Major) Use prilocaine and tricyclic antidepressants together with caution. If epinephrine is added to prilocaine, severe and prolonged hypertension may occur in a patient taking a TCA. Tricyclic antidepressants can increase the sensitivity to epinephrine by inhibiting epinephrine reuptake or metabolism. If concurrent therapy is necessary, carefully monitor the patient. Administration of a phenothiazine or a butyrophenone may reduce or reverse the pressor effect of epinephrine.
Prilocaine; Epinephrine: (Major) Avoid use of epinephrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the vasopressor effects of epinephrine. (Major) Use prilocaine and tricyclic antidepressants together with caution. If epinephrine is added to prilocaine, severe and prolonged hypertension may occur in a patient taking a TCA. Tricyclic antidepressants can increase the sensitivity to epinephrine by inhibiting epinephrine reuptake or metabolism. If concurrent therapy is necessary, carefully monitor the patient. Administration of a phenothiazine or a butyrophenone may reduce or reverse the pressor effect of epinephrine.
Primidone: (Moderate) Additive CNS and/or respiratory depression may occur. Additionally, barbiturates may increase the metabolism of chlordiazepoxide. Chlordiazepoxide is a CYP3A4 substrate. Barbiturates are CYP3A4 inducers. (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. In addition, pharmacokinetic interactions may occur. Barbiturates may increase TCA metabolism. Monitor patients during concurrent use.
Procarbazine: (Major) In general, drugs with MAOI activity, such as procarbazine, should not be used with tricyclic antidepressants. Severe hypertensive crises, serotonin syndrome, or increased anticholinergic effects can result from concomitant use. Tricyclic antidepressants can, in some cases, be used concomitantly with MAOIs if tricyclic antidepressant therapy is in effect prior to beginning therapy with a MAOI; tricyclic antidepressants should never be added to an existing MAOI regime. Under careful monitoring for signs or symptoms of hypertension, add the MAOI gradually, starting at a low dose. Patients should also be monitored closely for signs or symptoms of serotonin syndrome (characterized by hyperthermia, diaphoresis, shivering, tremor, myoclonus, seizures, ataxia, delirium, restlessness). Strict adherence to diet restrictions should be emphasized and the patient should not be receiving other sympathomimetics. Most references suggest avoiding this drug interaction entirely if clomipramine or imipramine are being administered. (Minor) CNS depressants benzodiazepines can potentiate the CNS depression caused by procarbazine therapy, so these drugs should be used together cautiously.
Prochlorperazine: (Moderate) When prescribing tricyclic antidepressants (TCAs) to patients already receiving phenothiazine therapy, close monitoring is essential and dose reduction may become necessary to avoid toxicity. Phenothiazines have been reported to prolong the QT interval. Because tricyclic antidepressants are associated with a possible risk for QT prolongation and TdP when given in excessive doses or overdosage, concurrent use with phenothiazines should be approached with caution. Lower doses than usually prescribed for either the phenothiazine or the TCA may be required. Additive anticholinergic effects and sedation may also occur.
Promethazine: (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant promethazine and tricyclic antidepressant use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
Promethazine; Dextromethorphan: (Moderate) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering dextromethorphan with tricyclic antidepressants. Inform patients taking this combination of the possible increased risk and monitor for the emergence of serotonin syndrome particularly during treatment initiation and dose adjustments. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant promethazine and tricyclic antidepressant use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects.
Promethazine; Phenylephrine: (Major) Tricyclic antidepressants (TCAs) may markedly enhance the pressor response to parenteral direct-acting sympathomimetic agents such as norepinephrine and, to a lesser extent, epinephrine and phenylephrine. TCAs inhibit norepinephrine reuptake in adrenergic neurons, resulting in increased stimulation of adrenergic receptors. Clinically, the patient might experience hypertension, headache, tremor, palpitations, chest pain, or irregular heartbeat. (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant promethazine and tricyclic antidepressant use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects. (Moderate) The therapeutic effect of phenylephrine may be decreased in patients receiving benzodiazepines. Monitor patients for decreased pressor effect if these agents are administered concomitantly.
Propafenone: (Minor) Tricyclic antidepressants (TCAs) share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). This pharmacologic property of the TCAs is of concern in patients with significant cardiac histories or treated with selected cardiac agents. Cases of long QT syndrome and torsade de pointes (TdP) tachycardia have been described with TCA use, but rarely occur when TCAs are used alone in normal prescribed doses and in the absence of other known risk factors for QT prolongation. Limited data are available regarding the safety of TCAs in combination with other QT-prolonging drugs. One study reported the common occurrence of overlapping prescriptions for 2 or more drugs with potential for QT-prolonging effects; antidepressants were involved in nearly 50% of the cases, but there are little data to document safety of the combined therapies. Certain cardiac drugs prolong repolarization at therapeutic or elevated plasma concentrations, and the addition of other drugs may increase the risk of QT prolongation and TdP via pharmacokinetic or pharmacodynamic interactions. TCAs should be used cautiously and with close monitoring in combination with cardiac drugs known to prolong the QT interval such as propafenone. The need to coadminister TCAs with propafenone should be done with a careful assessment of risk versus benefit; consider alternative therapy to the TCA.
Propantheline: (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and propantheline use. Concomitant use may result in additive anticholinergic adverse effects.
Propofol: (Moderate) Concomitant administration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. (Moderate) General anesthetics like propofol may produce additive CNS depression when used in patients taking tricyclic antidepressants.
Protease inhibitors: (Major) CYP3A4 inhibitors, such as protease inhibitors, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. A decrease in the chlordiazepoxide dose may be needed.
Pseudoephedrine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines.
Pseudoephedrine; Triprolidine: (Major) Avoid use of pseudoephedrine and tricyclic antidepressants as tricyclic antidepressants may potentiate the effects of catecholamines. (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Pyridostigmine: (Moderate) Tricyclic antidepressants may antagonize some of the effects of parasympathomimetics, such as pyridostigmine, due to their anticholinergic activity.
Pyrilamine: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Quazepam: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur.
Quetiapine: (Moderate) Somnolence is a commonly reported adverse effect of quetiapine; coadministration of quetiapine with anxiolytics, sedatives, and hypnotics, or other CNS depressants may result in additive sedative effects.
Quinidine: (Contraindicated) Quinidine administration is associated with QT prolongation and torsade de pointes (TdP). Quinidine inhibits CYP2D6 and has QT-prolonging actions. Quinidine is contraindicated with other drugs that prolong the QT interval and are metabolized by CYP2D6 as the effects on the QT interval may be increased during concurrent use of these agents. Tricyclic antidepressants are associated with a possible risk of QT prolongation, particularly at high dosages or in overdose, and are substrates for CYP2D6.
Quinine: (Major) Quinine has been associated with QT prolongation and rare cases of torsade de pointes (TdP). In addition, quinine is an inhibitor of CYP2D6. Avoid concurrent use of quinine with other drugs that prolong the QT and are CYP2D6 substrates. Coadministration may result in elevated plasma concentrations of the interacting drug, causing increased risk for adverse events, such as QT prolongation. Drugs that prolong the QT and are substrates for CYP2D6 include tricyclic antidepressants.
Racepinephrine: (Major) Tricyclic antidepressants (TCAs) and maprotiline potentiate the effects of sympathomimetics including epinephrine. Enhanced cardiovascular effects including arrhythmias, severe hypertension, and/or hyperpyrexia are possible with combined use. Concomitant use of racepinephrine inhalations with these agents should be avoided when possible; use caution when concomitant use is not avoidable. If a patient is taking these antidepressants, then they should seek health care professional advice prior to the use of racepinephrine.
Ramelteon: (Moderate) Ramelteon is a sleep-promoting agent; therefore, additive pharmacodynamic effects are possible when combining ramelteon with benzodiazepines or other miscellaneous anxiolytics, sedatives, and hypnotics. Pharmacokinetic interactions have been observed with the use of zolpidem. Use of ramelteon 8 mg/day for 11 days and a single dose of zolpidem 10 mg resulted in an increase in the median Tmax of zolpidem of about 20 minutes; exposure to zolpidem was unchanged. Ramelteon use with hypnotics of any kind is considered duplicative therapy and these drugs are generally not co-administered.
Ranolazine: (Major) Ranolazine is associated with dose- and plasma concentration-related increases in the QTc interval. The mean increase in QTc is about 6 milliseconds, measured at the tmax of the maximum dosage (1000 mg PO twice daily). However, in 5% of the population studied, increases in the QTc of at least 15 milliseconds have been reported. Although there are no studies examining the effects of ranolazine in patients receiving other QT prolonging drugs, coadministration of such drugs may result in additive QT prolongation. In addition, ranolazine and/or metabolites are moderate inhibitors of CYP2D6 isoenzymes. Based on drug interaction studies with metoprolol, a CYP2D6 substrate, ranolazine may theoretically increase plasma concentrations of CYP2D6 substrates and could lead to toxicity for drugs that have a narrow therapeutic range. The manufacturer for ranolazine suggests that lower doses of CYP2D6 substrates may be required during ranolazine treatment. Drugs that are CYP2D6 substrates that also have a possible risk for QT prolongation and TdP that should be used cautiously with ranolazine include tricyclic antidepressants. (Moderate) CYP3A4 inhibitors like ranolazine may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity.
Rasagiline: (Major) It is recommended to avoid concurrent use of rasagiline and antidepressants, including tricyclic antidepressants or related compounds (e.g., amoxapine, maprotiline). Severe CNS toxicity with hyperpyrexia has been reported during concurrent use of antidepressants and selective or non-selective MAOIs. During post-marketing use of rasagiline, non-fatal cases of serotonin syndrome have been reported during concomitant antidepressant administration. At least 2 weeks should elapse between stopping rasagiline treatment and beginning therapy with any tricyclic antidepressants or related compounds. Conversely, when discontinuing a tricyclic or related compound, it is advisable to wait the length of 4-5 half lives of the individual agent being discontinued prior to initiation with rasagiline. (Moderate) The CNS-depressant effects of MAOIs can be potentiated with concomitant administration of other drugs known to cause CNS depression including buprenorphine, butorphanol, dronabinol, THC, nabilone, nalbuphine, and anxiolytics, sedatives, and hypnotics. Use these drugs cautiously with MAOIs; warn patients to not drive or perform other hazardous activities until they know how a particular drug combination affects them. In some cases, the dosages of the CNS depressants may need to be reduced.
Relugolix; Estradiol; Norethindrone acetate: (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Remifentanil: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Benzodiazepine doses may need to be reduced up to 75% during coadministration with remifentanil. Educate patients about the risks and symptoms of respiratory depression and sedation. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation, somnolence, and increased risk of serotonin syndrome. The anticholinergic properties of tricyclic antidepressants may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression and serotonin syndrome. Monitor for signs of urinary retention and reduced gastric motility.
Remimazolam: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur. (Major) The sedative effect of remimazolam can be accentuated by chlordiazepoxide. Titrate the dose of remimazolam to the desired clinical response and continuously monitor sedated patients for hypotension, airway obstruction, hypoventilation, apnea, and oxygen desaturation.
Ribociclib: (Moderate) Monitor for an increase in chlordiazepoxide-related adverse reactions including sedation and respiratory depression if coadministration with ribociclib is necessary; adjust the dose of chlordiazepoxide if necessary. Ribociclib is a strong CYP3A4 inhibitor and chlordiazepoxide is a CYP3A4 substrate.
Ribociclib; Letrozole: (Moderate) Monitor for an increase in chlordiazepoxide-related adverse reactions including sedation and respiratory depression if coadministration with ribociclib is necessary; adjust the dose of chlordiazepoxide if necessary. Ribociclib is a strong CYP3A4 inhibitor and chlordiazepoxide is a CYP3A4 substrate.
Rifabutin: (Moderate) Rifabutin is a hepatic inducer and can theoretically increase the clearance of benzodiazpines metabolized by oxidative metabolism, including chlordiazepoxide, leading to lower benzodiazepine concentrations.
Rifampin: (Moderate) It may be necessary to adjust the dosage of tricyclic antidepressants if given concurrently with rifampin. Rifampin may induce the metabolism of tricyclic antidepressants; coadministration may result in decreased tricyclic antidepressant plasma concentrations. (Moderate) Several hepatic inducers, such as rifampin, can theoretically increase the clearance of benzodiazpines metabolized by oxidative metabolism, leading to lower benzodiazepine concentrations.
Rifapentine: (Major) Rifapentine induces hepatic isoenzymes CYP3A4 and CYP2C8/9. Tricyclic antidepressants are metabolized by CYP3A4 and CYP2C8/9 and may require dosage adjustments when administered concurrently with rifapentine.
Risperidone: (Moderate) Due to the primary CNS effects of risperidone, caution should be used when risperidone is given in combination with other centrally acting medications including anxiolytics, sedatives, and hypnotics. (Moderate) Use risperidone and tricyclic antidepressants together with caution due to the potential for additive QT prolongation and risk of torsade de pointes (TdP). Additionally, coadministration may result in additive CNS effects. Risperidone has been associated with a possible risk for QT prolongation and/or TdP, primarily in the overdose setting. Tricyclic antidepressants share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations).
Ritonavir: (Major) CYP3A4 inhibitors, such as protease inhibitors, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. A decrease in the chlordiazepoxide dose may be needed. (Moderate) Monitor for an increase in tricyclic antidepressant (TCA)-related adverse reactions if coadministration with ritonavir is necessary; a dose reduction of the TCA may be necessary. Concurrent use may increase exposure of the TCA. TCAs are CYP2D6 substrates and ritonavir is a CYP2D6 inhibitor.
Rivastigmine: (Moderate) Concurrent use of tricyclic antidepressants and rivastigmine should be avoided if possible. Rivastigmine inhibits acetylcholinesterase, the enzyme responsible for the degradation of acetylcholine, and improves the availability of acetylcholine. Tricyclic antidepressants with significant anticholinergic activity, such as amitriptyline, imipramine, doxepin, and clomipramine, are more likely to interfere with the therapeutic effect of rivastigmine than other tricyclics.
Rolapitant: (Major) Monitor for increased serum concentrations of amitriptyline and for amitriptyline-related adverse effects, such as nausea, dizziness, hypotension, syncope, and QT prolongation, if coadministered with rolapitant. Lower doses of either drug may be required with coadministration. When rolapitant is withdrawn from co-therapy, an increased dose of amitriptyline may be required. Amitriptyline is a CYP2D6 substrate, and rolapitant is a moderate CYP2D6 inhibitor; the inhibitory effect of rolapitant is expected to persist beyond 28 days for an unknown duration. Exposure to another CYP2D6 substrate, following a single dose of rolapitant increased about 3-fold on Days 8 and Day 22. The inhibition of CYP2D6 persisted on Day 28 with a 2.3-fold increase in the CYP2D6 substrate concentrations, the last time point measured.
Ropinirole: (Moderate) Concomitant use of ropinirole with other CNS depressants can potentiate the sedation effects of ropinirole. (Moderate) Ropinirole may cause additive drowsiness when combined with tricyclic antidepressants.
Rotigotine: (Major) Concomitant use of rotigotine with other CNS depressants, such as benzodiazepines, can potentiate the sedative effects of rotigotine.
Rucaparib: (Moderate) Monitor for an increase in amitriptyline-related adverse reactions if coadministration with rucaparib is necessary; a dose reduction of amitriptyline may be necessary. Concurrent use may increase the plasma concentrations of amitriptyline. Amitriptyline is a CYP2D6 substrate and rucaparib is a CYP2D6 inhibitor.
Rufinamide: (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. Monitor patients on anticonvulsants carefully when a TCA is used concurrently.
Safinamide: (Contraindicated) Safinamide is contraindicated for use with tricyclic antidepressants (TCAs) due to the risk of serotonin syndrome. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. At least 14 days should elapse between the discontinuation of safinamide and the initiation of a TCA. (Moderate) Dopaminergic medications, including safinamide, may cause a sudden onset of somnolence which sometimes has resulted in motor vehicle accidents. Patients may not perceive warning signs, such as excessive drowsiness, or they may report feeling alert immediately prior to the event. Because of possible additive effects, advise patients about the potential for increased somnolence during concurrent use of safinamide with other sedating medications, such as benzodiazepines.
Saquinavir: (Major) CYP3A4 inhibitors, such as protease inhibitors, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. A decrease in the chlordiazepoxide dose may be needed. (Minor) The concurrent use of saquinavir boosted with ritonavir and tricyclic antidepressants should be avoided if possible due to the potential for increased tricyclic antidepressant serum concentrations and the potential for QT prolongation. Saquinavir boosted with ritonavir is a potent inhibitor of CYP3A4, an isoenzyme partially responsible for the metabolism of many tricyclic antidepressants. During coadministration, elevated serum concentrations of the tricyclic antidepressant can occur; thus, monitoring of therapeutic concentrations is recommended by the manufacturer of saquinavir. Additionally, saquinavir boosted with ritonavir causes dose-dependent QT and PR prolongation; if possible, avoid use with other drugs that may prolong the QT or PR interval, such as tricyclic antidepressants. If no alternative therapy is acceptable, perform a baseline ECG prior to initiation of concomitant therapy and follow recommended ECG monitoring.
Scopolamine: (Moderate) Monitor for unusual drowsiness or excess sedation and for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and scopolamine use. Concomitant use may result in additive CNS depression or anticholinergic adverse effects. (Moderate) Scopolamine may cause dizziness and drowsiness. Concurrent use of scopolamine and CNS depressants can adversely increase the risk of CNS depression.
Secobarbital: (Moderate) Additive CNS and/or respiratory depression may occur. Additionally, barbiturates may increase the metabolism of chlordiazepoxide. Chlordiazepoxide is a CYP3A4 substrate. Barbiturates are CYP3A4 inducers. (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. In addition, pharmacokinetic interactions may occur. Barbiturates may increase TCA metabolism. Monitor patients during concurrent use.
Sedating H1-blockers: (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Segesterone Acetate; Ethinyl Estradiol: (Minor) Ethinyl estradiol may inhibit the clearance of benzodiazepines that undergo oxidation, thereby increasing serum concentrations of concomitantly administered benzodiazepines. (Minor) The oxidative metabolism of tricyclic antidepressants may be decreased by ethinyl estradiol. Increased antidepressant serum concentrations may occur. Ethinyl estradiol has been reported to intensify side effects from imipramine. Patients should be monitored for increased tricyclic antidepressant side effects if an estrogen is added. Current evidence indicates that this interaction may be related to the estrogen dosage, with larger doses (i.e., >= 50 mcg ethinyl estradiol/day) causing a more significant interaction.
Selegiline: (Contraindicated) Tricyclic antidepressants (TCAs) are contraindicated for use with selegiline, a selective monoamine oxidase type B inhibitor (MAO-B inhibitor). At least 14 days should elapse between discontinuation of selegiline and initiation of treatment with a TCA. After stopping treatment with a TCA, a time period equal to 4 to 5 half-lives of the TCA or any active metabolite should elapse before starting therapy with selegiline. Serotonin syndrome has occurred in patients receiving selective MAO-B inhibitors and such antidepressants simultaneously. (Moderate) Monitor for unusual drowsiness and sedation during coadministration of benzodiazepines and selegiline due to the risk for additive CNS depression.
Serotonin-Receptor Agonists: (Moderate) Monitor for signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant serotonin-receptor agonist and tricyclic antidepressant use. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for serotonin syndrome.
Sertraline: (Moderate) Monitor patients for signs and symptoms of serotonin syndrome during concomitant use of sertraline and amitriptyline, particularly during treatment initiation and dosage increases. If serotonin syndrome occurs, consider discontinuation of therapy. The concomitant use of serotonergic drugs increases the risk of serotonin syndrome.
Sevoflurane: (Moderate) Concomitant administration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. (Minor) Tricyclic antidepressants (TCAs) should be used cautiously and with close monitoring with halogenated anesthetics. Halogenated anesthetics can prolong the QT interval. Tricyclic antidepressants (TCAs) share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). In addition, general anesthetics may produce additive CNS depression when used in patients taking tricyclic antidepressants.
Sincalide: (Moderate) Sincalide-induced gallbladder ejection fraction may be affected by benzodiazepines. False study results are possible in patients with drug-induced hyper- or hypo-responsiveness; thorough patient history is important in the interpretation of procedure results.
Skeletal Muscle Relaxants: (Moderate) Concomitant use of skeletal muscle relaxants with benzodiazepines can result in additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given. Monitor patients who take benzodiazepines with another CNS depressant for symptoms of excess sedation.
Sodium Oxybate: (Contraindicated) Sodium oxybate should not be used in combination with CNS depressant anxiolytics, sedatives, and hypnotics or other sedative CNS depressant drugs. Specifically, sodium oxybate use is contraindicated in patients being treated with sedative hypnotic drugs. Sodium oxybate (GHB) has the potential to impair cognitive and motor skills. For example, the concomitant use of barbiturates and benzodiazepines increases sleep duration and may contribute to rapid onset, pronounced CNS depression, respiratory depression, or coma when combined with sodium oxybate.
Sodium picosulfate; Magnesium oxide; Anhydrous citric acid: (Minor) There have been reports of generalized tonic-clonic seizures with the use of bowel preparation products in patients with no prior history of seizures. While seizures have generally been associated with electrolyte abnormalities, such as hyponatremia, hypokalemia, hypocalcemia, and hypomagnesemia, and low serum osmolarity, patients receiving medications that lower the seizure threshold may be at an increased risk for experiencing seizures with bowel preparation products.
Solifenacin: (Moderate) Additive anticholinergic effects may be seen when drugs with antimuscarinic properties like solifenacin are used concomitantly with tricyclic antidepressants. Clinicians should note that additive antimuscarinic effects may be seen not only on GI smooth muscle, but also on bladder function, the CNS, the eye, and temperature regulation. Additive drowsiness may also occur, depending on the interacting agent. In addition, solifenacin is associated with dose-dependent QT prolongation, and torsades de pointes (TdP) has been reported with post-marketing use. Tricyclic antidepressants also are associated with QT prolongation and should be used cautiously and with close monitoring with solifenacin.
St. John's Wort, Hypericum perforatum: (Major) St. John's Wort may induce the hepatic CYP3A4 metabolism of chlordiazepoxide which is metabolized by oxidation. It would be prudent to avoid co-administration of St. John's Wort with chlordiazepoxide. Benzodiazepines that are not metabolized by CYP3A4 such as oxazepam or lorazepam may be alternatives if a benzodiazepine is required in combination with St. John's Wort. (Moderate) Monitor patients for the emergence of serotonin syndrome or for loss of tricyclic antidepressant (TCA) efficacy if concomitant use of TCAs and St. John's wort is warranted. The concomitant use of TCAs with other serotonergic drugs has resulted in serotonin syndrome. Also monitor patients for reduced efficacy of TCAs if used together. TCAs are metabolized by several hepatic isoenzymes, including CYP3A and CYP1A2 and St. John's wort is a strong inducer of these enzymes.
Stiripentol: (Moderate) Monitor for excessive sedation and somnolence during coadministration of stiripentol and chlordiazepoxide. CNS depressants can potentiate the effects of stiripentol. (Moderate) Monitor for excessive sedation and somnolence during coadministration of stiripentol and tricyclic antidepressants. CNS depressants can potentiate the effects of stiripentol.
Sufentanil: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation and somnolence. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Also monitor patients for the emergence of serotonin syndrome. Discontinue all serotonergic agents and initiate symptomatic treatment if serotonin syndrome occurs. The concomitant use of opioids with other drugs that affect the serotonergic neurotransmitter system has resulted in serotonin syndrome.
Sulfamethoxazole; Trimethoprim, SMX-TMP, Cotrimoxazole: (Moderate) Monitor for loss of tricyclic antidepressant efficacy during concomitant sulfamethoxazole; trimethoprim use; adjust the tricyclic antidepressant dose if needed. The efficacy of tricyclic antidepressants can decrease during concomitant use. (Moderate) Monitor therapeutic response and adjust the tricyclic antidepressant dose, if needed, when use sulfamethoxazole; trimethoprim concomitantly. The efficacy of tricyclic antidepressants can decrease when administered with sulfamethoxazole; trimethoprim.
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. These agents include the benzodiazepines. (Moderate) The use of suvorexant with other CNS depressants (e.g., tricyclic antidepressants) increases the risk of CNS depression. Dosage adjustments of suvorexant and of concomitant CNS depressants may be necessary when administered together because of potentially additive effects. The use of suvorexant with other drugs to treat insomnia, such as tricyclic antidepressants used for insomnia, is not recommended.
Tapentadol: (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 tapentadol is initiated in a patient taking a benzodiazepine, a reduced initial dosage of tapentadol is recommended. If the extended-release tapentadol tablets are used concurrently with a benzodiazepine, use an initial tapentadol dose of 50 mg PO every 12 hours. 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. (Major) Concomitant use of opioid agonists with tricyclic antidepressants may cause excessive sedation, somnolence, and increased risk of serotonin syndrome. The anticholinergic properties of tricyclic antidepressants may increase the risk of urinary retention and/or severe constipation, which may lead to paralytic ileus. Limit the use of opioid pain medications with tricyclic antidepressants to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. Educate patients about the risks and symptoms of excessive CNS depression and serotonin syndrome. Monitor for signs of urinary retention and reduced gastric motility.
Tedizolid: (Minor) Caution is warranted with the concurrent use of tedizolid and tricyclic antidepressants (TCAs) due to the theoretical risk of serotonin syndrome. Animal studies did not predict serontoneric effects with tedizolid. However, tedizolid is an antibiotic that is a weak reversible, non-selective MAO inhibitor and monoamine oxidase type A deaminates serotonin; therefore, coadministration theoretically could lead to serious reactions including serotonin syndrome or neuroleptic malignant syndrome-like reactions. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome.
Teduglutide: (Moderate) Altered mental status has been observed in patients taking teduglutide and benzodiazepines in the adult clinical studies for teduglutide. Careful monitoring and possible dose adjustment of the benzodiazepine agent may be required. Teduglutide has direct effects on the gut that may increase benzodiazepine exposure by improving oral absorption.
Temazepam: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur.
Terbinafine: (Moderate) In vitro studies have shown systemic terbinafine to inhibit hepatic isoenzyme CYP2D6, and thus may inhibit the clearance of drugs metabolized by this isoenzyme, such as tricyclic antidepressants.
Tetrabenazine: (Moderate) Concurrent use of tetrabenazine and drugs that can cause CNS depression, such as benzodiazepines, can increase both the frequency and the intensity of adverse effects such as drowsiness, sedation, dizziness, and orthostatic hypotension. (Moderate) Tetrabenazine causes a small increase in the corrected QT interval (QTc). The manufacturer recommends avoiding concurrent use of tetrabenazine with other drugs known to prolong QTc such as tricyclic antidepressants. Tricyclic antidepressants (TCAs) share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). In addition, concurrent use of tricyclics and tetrabenazine should generally be avoided since the risk of adverse effects such as drowsiness, sedation, dizziness, or orthostatic hypotension may be increased.
Tetracaine: (Major) Use tetracaine and tricyclic antidepressants (TCAs) together with caution. If epinephrine is added to tetracaine, severe and prolonged hypertension may occur in a patient taking a TCA. Tricyclic antidepressants can increase the sensitivity to epinephrine by inhibit ing epinephrine reuptake or metabolism. If concurrent therapy is necessary, carefully monitor the patient. Administration of a phenothiazine or a butyrophenone may reduce or reverse the pressor effect of epinephrine.
Thalidomide: (Major) Avoid the concomitant use of thalidomide with other central nervous system depressants such as tricyclic antidepressants (TCAs) due to the potential for additive sedative effects. Additionally, co-administration of thalidomide and other agents that slow cardiac conduction such as TCAs may increase the potential for additive bradycardia. (Major) The use of benzodiazepine anxiolytics, sedatives, or hypnotics with thalidomide may cause an additive sedative effect and should be avoided. Thalidomide frequently causes drowsiness and somnolence. Dose reductions may be required. Patients should be instructed to avoid situations where drowsiness may be a problem and not to take other medications that may cause drowsiness without adequate medical advice. Advise patients as to the possible impairment of mental and/or physical abilities required for the performance of hazardous tasks, such as driving a car or operating other complex or dangerous machinery.
Theophylline, Aminophylline: (Minor) Aminophylline or Theophylline have been reported to counteract the pharmacodynamic effects of diazepam and possibly other benzodiazepines. The clinical significance of this interaction is not certain. A proposed mechanism is competitive binding of these methylxanthines to adenosine receptors in the brain. If such therapy is initiated or discontinued, monitor the clinical response to the benzodiazepine.
Thioridazine: (Contraindicated) Thioridazine is associated with a well-established risk of QT prolongation and torsades de pointes (TdP). Thioridazine is considered contraindicated for use along with agents that, when combined with a phenothiazine, may prolong the QT interval and increase the risk of TdP, and/or cause orthostatic hypotension, including tricyclic antidepressants (TCAs). In addition to additive effects on the cardiovascular system, additive anticholinergic effects and sedation may be observed.
Thiothixene: (Moderate) Concurrent use of thiothixene and tricyclic antidepressants (TCAs) may result in additive anticholinergic effects, sedation, and orthostatic hypotension. Additive effects may be more pronounced when thiothixene is used with tertiary TCAs including amitriptyline, clomipramine, doxepin, imipramine, and trimipramine versus secondary TCAs such as desipramine, nortriptyline, and protriptyline. (Moderate) Thiothixene can potentiate the CNS-depressant action of other drugs such as benzodiazepines. Caution should be exercised during simultaneous use of these agents due to potential excessive CNS effects or additive hypotension.
Thyroid hormones: (Minor) Thyroid hormones may increase receptor sensitivity and enhance the effects of tricyclic antidepressants. Although this drug combination appears to be safe, be aware of the possibility of exaggerated cardiovascular side effects such as arrhythmias and CNS stimulation.
Tiagabine: (Moderate) Because of the possible additive effects of drugs that depress the central nervous system, benzodiazepines should be used with caution in patients receiving tiagabine. (Moderate) Tricyclic antidepressants, when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold.
Tipranavir: (Major) CYP3A4 inhibitors, such as protease inhibitors, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity. A decrease in the chlordiazepoxide dose may be needed.
Tizanidine: (Moderate) Concurrent use of tizanidine and CNS depressants like the benzodiazepines can cause additive CNS depression. The severity of this interaction may be increased when additional CNS depressants are given.
Tobacco: (Major) Advise patients to avoid smoking tobacco while taking tricyclic antidepressants (TCAs). Tobacco smoking may increase the clearance of TCAs, which may reduce their efficacy.
Tolcapone: (Major) COMT inhibitors should be given cautiously with other agents that cause CNS depression, including tricyclic antidepressants, due to the possibility of additive sedation. COMT inhibitors have also been associated with sudden sleep onset during activities of daily living such as driving, which has resulted in accidents in some cases. Prescribers should re-assess patients for drowsiness or sleepiness regularly throughout treatment, especially since events may occur well after the start of treatment. Patients should be advised to avoid driving or other tasks requiring mental alertness until they know how the combination affects them.
Tolterodine: (Moderate) Tricyclic antidepressants (TCAs) should be used cautiously and with close monitoring with tolterodine. TCAs share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). Tolterodine is also associated with dose-dependent prolongation of the QT interval, especially in poor metabolizers of CYP2D6. In addition, additive anticholinergic effects may be seen when tricyclic antidepressants (TCAs) are used concomitantly with other antimuscarinics. Clinicians should note that antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. Additive CNS effects are also possible when tolterodine is combined with tricyclic antidepressants.
Topiramate: (Moderate) Monitor for unusual drowsiness or excess sedation and for increased amitriptyline-related adverse events during concomitant topiramate use. Concomitant use resulted in an increase in amitriptyline exposure by 12% and may increase the risk for additive CNS depression. (Moderate) Topiramate has the potential to cause CNS depression as well as other cognitive and/or neuropsychiatric adverse reactions. The CNS depressant effects of topiramate can be potentiated pharmacodynamically by concurrent use of CNS depressant agents such as the benzodiazepines.
Tramadol: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. (Major) Concomitant use of tramadol with tricyclic antidepressants may cause respiratory depression, hypotension, profound sedation, and death and increase the risk for serotonin syndrome, seizures, and anticholinergic effects. Limit the use of opioid pain medications to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Monitor patients for serotonin syndrome if concomitant use is necessary, particularly during treatment initiation and dosage increases. If serotonin syndrome occurs, consider discontinuation of therapy. The concomitant use of serotonergic drugs increases the risk of serotonin syndrome. Monitor for signs of urinary retention or reduced gastric motility during coadministration. The concomitant use of anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Tramadol; Acetaminophen: (Major) Concomitant use of opiate agonists with benzodiazepines may cause respiratory depression, hypotension, profound sedation, and death. Limit the use of opiate pain medications with benzodiazepines to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, use the lowest effective doses and minimum treatment durations needed to achieve the desired clinical effect. If an opiate agonist is initiated in a patient taking a benzodiazepine, use a lower initial dose of the opiate and titrate to clinical response. If a benzodiazepine is prescribed for an indication other than epilepsy in a patient taking an opiate agonist, use a lower initial dose of the benzodiazepine and titrate to clinical response. Educate patients about the risks and symptoms of respiratory depression and sedation. (Major) Concomitant use of tramadol with tricyclic antidepressants may cause respiratory depression, hypotension, profound sedation, and death and increase the risk for serotonin syndrome, seizures, and anticholinergic effects. Limit the use of opioid pain medications to only patients for whom alternative treatment options are inadequate. If concurrent use is necessary, reduce initial dosage and titrate to clinical response; use the lowest effective doses and minimum treatment durations. Monitor patients for serotonin syndrome if concomitant use is necessary, particularly during treatment initiation and dosage increases. If serotonin syndrome occurs, consider discontinuation of therapy. The concomitant use of serotonergic drugs increases the risk of serotonin syndrome. Monitor for signs of urinary retention or reduced gastric motility during coadministration. The concomitant use of anticholinergic drugs may increase risk of urinary retention and/or severe constipation, which may lead to paralytic ileus.
Trandolapril; Verapamil: (Moderate) Verapamil is a CYP3A4 inhibitor and may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity.
Trazodone: (Major) Monitor for excessive sedation and somnolence during coadministration of trazodone and benzodiazepines. Concurrent use may result in additive CNS depression. (Moderate) Monitor for unusual drowsiness and excess sedation and signs and symptoms of serotonin syndrome, particularly during treatment initiation and dosage increase, during concomitant trazodone and tricyclic antidepressant use. If serotonin syndrome occurs, discontinue therapy. Concomitant use increases the risk for additive CNS depression and serotonin syndrome.
Triazolam: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur.
Tricyclic antidepressants: (Major) Limit dosage and duration of benzodiazepines during concomitant use with tricyclic antidepressants, and monitor patients closely for respiratory depression and sedation. Additive CNS depression may occur.
Trifluoperazine: (Moderate) Phenothiazines have been reported to prolong the QT interval. Because tricyclic antidepressants are associated with a possible risk for QT prolongation and TdP when given in excessive doses or overdosage, concurrent use with trifluoperazine should be approached with caution. If coadministration is considered necessary, and the patient has known risk factors for cardiac disease or arrhythmia, then close monitoring is essential. Additive anticholinergic effects or sedation may be seen when phenothiazines are used with tricyclic antidepressants.
Trihexyphenidyl: (Moderate) CNS depressants, such as anxiolytics, sedatives, and hypnotics, can increase the sedative effects of trihexyphenidyl. (Moderate) Monitor for signs or symptoms of anticholinergic toxicity during concomitant tricyclic antidepressant and trihexyphenidyl use. Concomitant use may result in additive anticholinergic adverse effects.
Trimethobenzamide: (Moderate) The concurrent use of trimethobenzamide with other medications that cause CNS depression, like the benzodiazepines, may potentiate the effects of either trimethobenzamide or the benzodiazepine.
Trimethoprim: (Moderate) Monitor therapeutic response and adjust the tricyclic antidepressant dose, if needed, when use sulfamethoxazole; trimethoprim concomitantly. The efficacy of tricyclic antidepressants can decrease when administered with sulfamethoxazole; trimethoprim.
Triprolidine: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants are used concomitantly with sedating H1-blockers. Antimuscarinic effects might be seen not only on GI smooth muscle, but also on bladder function, the eye, and temperature regulation. (Moderate) Coadministration can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. Use caution with this combination.
Trospium: (Moderate) Additive anticholinergic and CNS effects may be seen when tricyclic antidepressants (TCAs) are used concomitantly with other antimuscarinics, such as trospium. Antimuscarinic effects might be seen on GI smooth muscle, bladder function, the eye, and temperature regulation. While CNS-related side effects such as drowsiness and blurred vision are not typically noted with trospium, they may occur in some patients. Monitor for anticholinergic effects such as such as confusion, constipation, dizziness, urinary retention, dry mouth and eyes, blurred vision, or rarely, fast, irregular heartbeat.
Tryptophan, 5-Hydroxytryptophan: (Major) The concomitant use of tryptophan with tricyclic antidepressants should be avoided. Since tryptophan is converted to serotonin (5-hydroxytryptamine), the use of tryptophan in patients receiving drugs with serotonergic activity could lead to serotonin syndrome. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. If serotonin syndrome is suspected, the tricyclic antidepressant and concurrent serotonergic agents should be discontinued.
Tucatinib: (Moderate) Monitor for an increase in chlordiazepoxide-related adverse reactions including sedation and respiratory depression if coadministration with tucatinib is necessary; adjust the dose of chlordiazepoxide if necessary. Tucatinib is a strong CYP3A4 inhibitor and chlordiazepoxide is a CYP3A4 substrate.
Valerian, Valeriana officinalis: (Major) Any substances that act on the CNS, including psychoactive drugs and drugs used as anesthetic adjuvants (e.g., barbiturates, benzodiazepines), 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. These interactions are probably pharmacodynamic in nature. There is a possibility of interaction with valerian at normal prescription dosages of anxiolytics, sedatives, and hypnotics (including barbiturates and benzodiazepines). Patients who are taking barbiturates or other sedative/hypnotic drugs should avoid concomitant administration of valerian. Patients taking medications such as tricyclic antidepressants, lithium, MAOIs, skeletal muscle relaxants, SSRIs and serotonin norepinephrine reuptake inhibitors (e.g., duloxetine, venlafaxine) should discuss the use of herbal supplements with their health care professional prior to consuming valerian; combinations should be approached with caution in the absence of clinical data. Patients should not abruptly stop taking their prescribed psychoactive medications. (Moderate) Any substances that act on the CNS, including tricyclic antidepressants, 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. Valerian is probably best avoided in combination with prescription antidepressants unless closely monitored by a health care professional.
Valproic Acid, Divalproex Sodium: (Moderate) Tricyclic antidepressants, when used concomitantly with valproic acid, can increase CNS depression and may lower the seizure threshold. In addition, administration of a single oral 50 mg dose of amitriptyline to 15 normal volunteers who received valproate orally (500 mg twice daily) resulted in a 21% decrease in plasma clearance of amitriptyline and a 34% decrease in the net clearance of nortriptyline. Rare post-marketing reports of concurrent use of valproate and amitriptyline resulting in an increased amitriptyline level have been received; but, concurrent use has rarely been associated with toxicity. Monitoring of amitriptyline levels should be considered for patients taking valproate concomitantly with amitriptyline; a reduction in the dose of amitriptyline may be required.
Vasopressin, ADH: (Moderate) Monitor hemodynamics and adjust the dose of vasopressin as needed when used concomitantly with drugs suspected of causing syndrome of inappropriate antidiuretic hormone (SIADH), such as tricyclic antidepressants. Use together may increase the pressor and antidiuretic effects of vasopressin.
Venlafaxine: (Major) The combination of venlafaxine and tricyclic antidepressants may lead to serotonin syndrome and increased plasma concentrations of TCAs. Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering serotonin norepinephrine reuptake inhibitors (SNRIs) with other drugs that have serotonergic properties such as tricyclic antidepressants. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. Venlafaxine is an inhibitor of CYP2D6, and many TCAs are metabolized by this isozyme. One case report documented a first-time seizure in a patient receiving venlafaxine and trimipramine at therapeutic dosages.
Verapamil: (Moderate) Verapamil is a CYP3A4 inhibitor and may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity.
Verteporfin: (Moderate) Use caution if coadministration of verteporfin with tricyclic antidepressants is necessary due to the risk of increased photosensitivity. Verteporfin is a light-activated drug used in photodynamic therapy; all patients treated with verteporfin will be photosensitive. Concomitant use of other photosensitizing agents like antidepressants may increase the risk of a photosensitivity reaction.
Vigabatrin: (Moderate) Tricyclic antidepressants (TCAs), when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold, leading to pharmacodynamic interactions. (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 in combination with benzodiazepines.
Vilazodone: (Major) Vilazodone and Tricyclic antidepressants (TCAs) may cause additive CNS depression, including dizziness or drowsiness. These drugs can represent duplicate therapies and are not commonly prescribed together. In addition, because of the potential risk and severity of serotonin syndrome, caution should be observed. Serotonin syndrome is characterized by the rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Patients receiving vilazodone and a TCA should be monitored for the emergence of serotonin syndrome, particularly during treatment initiation and during dosage increases. Vilazodone and the TCA should be discontinued if serotonin syndrome occurs and supportive symptomatic treatment should be initiated. (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 the benzodiazepines.
Viloxazine: (Moderate) Monitor for an increase in tricyclic antidepressant (TCA)-related adverse reactions if coadministration with viloxazine is necessary; a dose reduction of TCA may be necessary. Concurrent use may increase the exposure of TCAs which are CYP2D6 substrates; viloxazine is a CYP2D6 inhibitor.
Vonoprazan; Amoxicillin; Clarithromycin: (Moderate) CYP3A4 inhibitors, such as clarithromycin, may reduce the metabolism of chlordiazepoxide and increase the potential for benzodiazepine toxicity.
Voriconazole: (Moderate) Monitor for an increase in chlordiazepoxide-related adverse reactions including sedation and respiratory depression if coadministration with voriconazole is necessary; adjust the dose of chlordiazepoxide if necessary. Voriconazole is a strong CYP3A4 inhibitor and chlordiazepoxide is a CYP3A4 substrate. (Minor) Due to the potential for QT prolongation and torsade de pointes (TdP), caution is advised when administering voriconazole with amitriptyline. Voriconazole has been associated with prolongation of the QT interval and rare cases of arrhythmias, including TdP. Tricyclic antidepressants (TCAs), such as amitriptyline, share pharmacologic properties similar to the Class IA antiarrhythmic agents and may prolong the QT interval, particularly in overdose or with higher-dose prescription therapy (elevated serum concentrations). In addition, voriconazole inhibits CYP3A4 and amitriptyline is partially metabolized by CYP3A4. Coadministration may result in elevated amitriptyline serum concentrations. Monitor for an increased response to amitriptyline if coadministered with voriconazole.
Vortioxetine: (Major) Because of the potential risk and severity of serotonin syndrome, caution should be observed when administering vortioxetine with other drugs that have serotonergic properties such as tricyclic antidepressants. Serotonin syndrome is characterized by rapid development of hyperthermia, hypertension, myoclonus, rigidity, autonomic instability, mental status changes (e.g., delirium or coma), and in rare cases, death. Serotonin syndrome, in its most severe form, can resemble neuroleptic malignant syndrome. Patients receiving a tricyclic antidepressant in combination with vortioxetine should be monitored for the emergence of serotonin syndrome or other adverse effects. If serotonin syndrome is suspected, vortioxetine and concurrent serotonergic agents should be discontinued.
Warfarin: (Moderate) Chlordiazepoxide has been associated with a decreased anticoagulation response to warfarin. Monitor coagulation parameters and adjust warfarin dosage as needed.
Zafirlukast: (Moderate) In vitro data indicate that zafirlukast inhibits the CYP2C9 and CYP3A4 isoenzymes at concentrations close to the clinically achieved total plasma concentrations. Until more clinical data are available, zafirlukast should be used cautiously in patients stabilized on drugs metabolized by CYP3A4, such as chlordiazepoxide.
Zaleplon: (Major) Monitor for excessive sedation and somnolence during coadministration of zaleplon and benzodiazepines. Concurrent use may result in additive CNS depression. If used together, a reduction in the dose of one or both drugs may be needed. (Moderate) Monitor for unusual drowsiness and sedation during coadministration of tricyclic antidepressants and zaleplon due to the risk for additive CNS depression and next-day psychomotor impairment; dose adjustments may be necessary. Coadministration of single doses of a tricyclic antidepressant and zaleplon produced additive effects on decreased alertness and impaired psychomotor performance for 2 to 4 hours after administration.
Ziconotide: (Moderate) Due to potentially additive effects, dosage adjustments may be necessary if ziconotide is used with a drug that has CNS depressant effects such as tricyclic antidepressants. Coadministration of CNS depressants may increase drowsiness, dizziness, and confusion that are associated with ziconotide.
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.
Zolpidem: (Major) Concomitant administration of benzodiazepines with zolpidem can potentiate the CNS effects (e.g., increased sedation or respiratory depression) of either agent. If used together, a reduction in the dose of one or both drugs may be needed. For Intermezzo brand of sublingual zolpidem tablets, reduce the dose to 1.75 mg/night. Concurrent use of zolpidem with other sedative-hypnotics, including other zolpidem products, at bedtime or the middle of the night is not recommended. 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. (Moderate) Monitor for unusual drowsiness and sedation during coadministration of tricyclic antidepressants and zolpidem due to the risk for additive CNS depression and next-day psychomotor impairment; dose adjustments may be necessary. Limit the dose of Intermezzo sublingual tablets to 1.75 mg/day. Coadministration of a tricyclic antidepressant and zolpidem resulted in a 20% decrease in the peak concentrations of the tricyclic antidepressant, but there was an additive effect of decreased alertness.
Zonisamide: (Moderate) Tricyclic antidepressants, when used concomitantly with anticonvulsants, can increase CNS depression and may also lower the seizure threshold. Monitor patients on anticonvulsants carefully when a TCA is used concurrently.

Amitriptyline Hydrochloride, Chlordiazepoxide Hydrochloride/Amitriptyline, Chlordiazepoxide/Limbitrol/Limbitrol DS Oral Tab: 12.5-5mg, 25-10mg

Adults

60 mg/day PO chlordiazepoxide and 150 mg/day PO amitriptyline.

Geriatric

60 mg/day PO chlordiazepoxide and 150 mg/day PO amitriptyline; however, lower total daily doses are usually recommended in the elderly versus younger adults.

Adolescents

Safety and efficacy have not been established.

Children

Safety and efficacy have not been established.

Chlordiazepoxide; amitriptyline are combined in a single formulation for antianxiety effects (chlordiazepoxide) and antidepressant effects (amitriptyline). The additive effects of these two drugs may help to control depression characterized by symptoms of anxiety.
Chlordiazepoxide: Benzodiazepines act at the level of the limbic, thalamic, and hypothalamic regions of the CNS to produce CNS depression. Recent evidence indicates that benzodiazepines exert their effects through enhancement of the gamma-aminobutyric acid (GABA)-benzodiazepine receptor complex. GABA is an inhibitory neurotransmitter that exerts its effects at specific receptor subtypes designated GABA-A and GABA-B. GABA-A is the primary receptor subtype in the CNS and is thought to be involved in the actions of anxiolytics and sedatives.
Amitriptyline: Although the exact mechanism is not known, amitriptyline appears to result in decreased reuptake of both norepinephrine and serotonin (5-HT). Amitriptyline is metabolized to nortriptyline, which accounts for most of the norepinephrine-reuptake inhibition after amitriptyline administration. Nortriptyline itself also possesses antidepressant activity. The down-regulation of limbic beta-receptors that results from this synaptic neurotransmitter increase occurs about 5 to 7 days after therapeutic concentrations are reached. Amitriptyline or nortriptyline do not result in monoamine oxidase inhibition and do not affect dopamine reuptake. Amitriptyline possesses strong anticholinergic activity. Sedation, which may be a useful therapeutic effect, may occur. The seizure threshold may be lowered. Cardiac dysrhythmias can result from the direct quinidine-like effect on cardiac function combined with anticholinergic activity and norepinephrine potentiation. Changes in sex hormone concentrations and blood glucose can result from amitriptyline's effect on the endocrine system.

Chlordiazepoxide; amitriptyline is administered orally.
Chlordiazepoxide: Chlordiazepoxide distributes throughout the body and is about 96% protein-bound. It crosses the CSF and placenta and is distributed into breast milk. It undergoes oxidative metabolism in the liver, producing several active metabolites. Chlordiazepoxide and its metabolites have a half-life ranging anywhere from 5 to 100 hours. The main active metabolite, desmethyldiazepam, has a half-life of several days. Repeated dosing may lead to drug accumulation, particularly in liver disease. Elimination occurs primarily as active metabolites in the urine.
Amitriptyline: The full antidepressant effect of amitriptyline can take several weeks, although adverse effects can occur after the first dose. Tricyclic antidepressants are highly protein-bound (predominantly to alpha1-acid glycoprotein) in plasma and tissues. Amitriptyline is demethylated in the liver to its primary metabolite nortriptyline, which is lipophilic and crosses the blood-brain barrier. Amitriptyline and nortriptyline are distributed into the lungs, heart, brain, and liver. Nortriptyline is known to cross the placenta and is also distributed into breast milk. Both nortriptyline and amitriptyline undergo enterohepatic circulation. Lipophilic metabolites, such as nortriptyline, are most likely to be reabsorbed and further metabolized. Amitriptyline undergoes hepatic cytochrome P450 metabolism via 3A4, 2C9, and 2D6 isozymes and one unidentified enzyme. Both amitriptyline and nortriptyline undergo CYP2D6 hydroxylation. Half-life values range from 10 to 50 hours (average value = 27 hours) for amitriptyline and 20 to 100 hours (average value = 33 hours) for nortriptyline. Between 25% to 50% of a single dose is excreted in urine as active metabolites within 24 hours. A small amount of excretion occurs in feces.
 
Affected cytochrome P450 isoenzyme sand drug transporters: CYP3A4, CYP2C9, CYP2D6

Oral Route

Chlordiazepoxide: Orally administered chlordiazepoxide is rapidly absorbed across the GI tract with 100% bioavailability. A reduction in anxiety is usually evident within 45 minutes following an oral dose, but this response correlates with the steady-state plasma levels of the active metabolites rather than of the parent drug.
Amitriptyline: Amitriptyline is well absorbed from the GI tract, but individual response can vary considerably. Peak plasma concentrations are obtained in roughly 4 hours following oral administration with steady-state achieved within 4 days.

Pregnancy

Due to a lack of data and the potential for serious adverse reactions, including sedation and withdrawal symptoms in breastfed infants, avoid the use of chlordiazepoxide; amitriptyline during breast-feeding. Based on studies with other benzodiazepines, it can be anticipated that chlordiazepoxide and its metabolites are excreted into breast milk. Monitor breastfed infants exposed to benzodiazepines through breast milk for sedation, poor feeding, and poor weight gain. Neonates metabolize benzodiazepines more slowly than adults and, when used chronically, accumulation may occur in the infant producing sedation, nausea, poor feeding, or other adverse effects. Many tricyclic antidepressants (TCAs), including amitriptyline, are also excreted into breast milk.