This monograph describes a medication approved for use in Canada by the Therapeutic Products Directorate, a division of Health Canada’s Health Products and Food Branch. The medication is not approved by the United States Food and Drug Administration; however, a similar formulation carrying a different generic or brand name might be available in the US.
monamine oxidase inhibitors
Treatment of depression.
- Short-acting, reversible inhibitor of monoamine oxidase type A.
- Increases concentrations of serotonin, norepinephrine, and dopamine.
Decreased symptoms of depression, with improved mood and quality of life.
Absorption: 98% absorbed following oral administration, but undergoes first-pass hepatic metabolism resulting in 90% bioavailability.
Metabolism and Excretion: Extensively metabolized (partially by CYP2C19 and CYP2D6), very small amounts are pharmacologically active, less than 1% excreted unchanged in urine.
Half-life: 1.5 hr (↑ with dose).
|PO||days–several wk (antidepressant effect)||0.5–3.5 hr (blood levels)||24 hr (MAO-A inhibition)|
- Known hypersensitivity;
- Acute confusional states;
- Concurrent use of tricyclic antidepressants;
- Concurrent use of SSRIs or other MAO inhibitors;
- Concurrent use of dextromethorphan, meperidine, selegiline, or thioridazine;
- Pedi: Safety not established, use is not recommended.
Use Cautiously in:
- History of suicide attempt or ideation;
- History of thyrotoxicosis or pheochromocytoma (possible risk of hypertensive reaction);
- Severe hepatic impairment (↓ dose required);
- Renal impairment;
- OB: Should not be used unless anticipated benefits justify potential harm to fetus;
- Lactation: Not recommended unless anticipated benefits justify potential harm to infant.
Adverse Reactions/Side Effects
CNS: SUICIDAL IDEATION, agitation, insomnia, restlessness, tremor
* CAPITALS indicate life-threatening.
Underline indicate most frequent.
- ↑ levels and risk of QT prolongation with thioridazine, avoid concurrent use.
- Concurrent use with selegiline greatly ↑ sensitivity to tyramine and is contraindicated.
- Concurrent use with tricyclic antidepressants may result in severe adverse reactions and is contraindicated.
- Should not be used with SSRIs or other MAO inhibitors ; when making a switch allow 4–5 half-lives of previous drug; for fluoxetine wait at least 5 wk.
- Exessive alcohol should be avoided.
- Cimetidine ↓ metabolism and ↑ blood levels, ↓ moclobemide dose by 50%.
- Because of the potential for interactions with anesthetics, especially local anesthetics containing epinephrine, moclobemide should be discontinued at least 2 days prior to procedures.
- Concurrent use with opioids should be avoided; dosage adjustments may be necessary.
- Concurrent use of sympathomimetics including ephedrine and amphetamines may ↑ blood pressure and should be avoided.
- Concurrent use with dextromethorphan may result in vertigo, tremor, nausea and vomiting and should be avoided.
- Concurrent use with antihypertensives should be carefully monitored.
Ingestion of large amounts of tyramine-containing foods including some cheeses and Marmite yeast extract may result in hypertension and arrhythmias and should be undertaken with caution.
PO (Adults): 150 mg twice daily initially; may be ↑ gradually after one wk as needed/tolerated up to 600 mg/day.
PO (Adults): Severe hepatic impairment or concurrent enzyme inhibitor (cimetidine)– ↓ daily dose to ⅓ to ½ of standard dose.
Tablets: 100 mg, 150 mg, 300 mg
- Assess mental status for orientation, mood, behavior, and anxiety. Assess for suicidal tendencies. Restrict amount of drug available to patient.
- Monitor BP and pulse before and frequently during therapy. Report significant changes promptly.
Monitor mood changes. Assess for suicidal tendencies, especially during early therapy. Restrict amount of drug available to patient.
- Monitor intake and output ratios and daily weight. Assess patient for peripheral edema and urinary retention.
Lab Test Considerations:
Monitor liver and kidney function periodically during treatment.
- Monitor serum glucose closely in diabetic patients; hypoglycemia may occur.
Toxicity and Overdose:
Concurrent ingestion of tyramine-rich foods and many medications may result in a life-threatening hypertensive crisis. Signs and symptoms of hypertensive crisis include chest pain, tachycardia, severe headache, nausea and vomiting, photosensitivity, and enlarged pupils. Treatment includes IV phentolamine.
- Symptoms of overdose include anxiety, irritability, tachycardia, hypertension or hypotension, respiratory distress, dizziness, drowsiness, hallucinations, confusion, seizures, fever, and diaphoresis. Treatment includes induction of vomiting or gastric lavage and supportive therapy as symptoms arise.
- Ineffective coping
- Noncompliance (Patient/Family/Teaching)
- Administer after meals. Swallow tablet whole; do not crush, break, or chew. Dose may be adjusted gradually during the first wk of therapy.
- Instruct patient to take medication as directed. Take missed doses if remembered unless almost time for next dose; do not double doses. Do not discontinue abruptly; withdrawal symptoms (nausea, vomiting, malaise, nightmares, agitation, psychosis, seizures) may occur. Advise patient to read Patient Information leaflet prior to starting and with each Rx refill in case of changes.
- Caution patient to avoid alcohol, CNS depressants, OTC drugs, and foods or beverages containing tyramine (see food sources for specific nutrients) during and for at least 2 wk after therapy has been discontinued; they may precipitate a hypertensive crisis. Contact health care professional immediately if symptoms of hypertensive crisis develop.
- Caution patient to notify health care professional if neck stiffness, changes in vision, diarrhea, constipation, rapid/pounding heartbeat, sudden and severe headache, stiff neck, confusion, disorientation, slurred speech, behavioral changes, seizures.
Advise patient and family to notify health care professional if thoughts about suicide or dying, attempts to commit suicide; new or worse depression; new or worse anxiety; feeling very agitated or restless; panic attacks; trouble sleeping; new or worse irritability; acting aggressive; being angry or violent; acting on dangerous impulses; an extreme increase in activity and talking; other unusual changes in behavior or mood occur.
- Instruct patient to carry identification describing medication regimen.
- Advise female patients to notify health care professional if pregnancy is planned or suspected or if breast feeding.
- Encourage patient to participate in psychotherapy in conjunction with taking medication.
- Improved mood in depressed patients.
- Decreased anxiety.