Classifications: psychotherapeutic; antidepressant; monoamine oxidase inhibitor (maoi) ;
Therapeutic: antidepressant
; maoi
Prototype: Phenelzine
Pregnancy Category: C


10 mg tablets


MAO INHIBITOR of the hydrazine group. Inhibits monoamine oxidase, the enzyme involved in the catabolism of catecholamine neurotransmitters and serotonin.

Therapeutic Effect

Effectiveness as an antidepressant is due to its inhibition of MAO.


Symptomatic treatment of depressed patients refractory to or intolerant of TCAs or electroconvulsive therapy.


Hypersensitivity to MAO INHIBITORs; pheochromocytoma; children (<16 y); older adults (>60 y) or debilitated patients; cardiac arrhythmias, hypertension, CHF, MI; severe renal or hepatic impairment; increased intracranial pressure, stroke, head trauma; pregnancy (category C), lactation.

Cautious Use

Hyperthyroidism, parkinsonism, epilepsy, schizophrenia; psychosis; suicidal risks or ideation.

Route & Dosage

Refractory Depression
Adult: PO 10–30 mg/d in 1–3 divided doses (max: 30 mg/d)


  • Note: Dosage is individualized on the basis of patient response. Lowest effective dosage should be used.
  • Store in a tight, light-resistant container.

Adverse Effects (≥1%)

CNS: Dizziness, light-headedness, tiredness, weakness, drowsiness, vertigo, headache, overactivity, hyperreflexia, muscle twitching, tremors, mania hypomania, insomnia, confusion, memory impairment. CV: Orthostatic hypotension, paradoxical hypertension, palpitation, tachycardia, other arrhythmias. Special Senses: Blurred vision, nystagmus, glaucoma. GI: Increased appetite, weight gain, nausea, diarrhea, constipation, anorexia, black tongue, dry mouth, abdominal pain. Urogenital: Dysuria, urinary retention, incontinence, sexual disturbances. Body as a Whole: Peripheral edema, excessive sweating, chills, skin rash, hepatitis, jaundice.


Drug: tricyclic antidepressants, fluoxetine, amphetamines, ephedrine, phenylpropanolamine, reserpine, guanethidine, buspirone, methyldopa, dopamine, levodopa, tryptophan may precipitate hypertensive crisis, headache, or hyperexcitability; alcohol and other cns depressants compound CNS depressant effects; meperidine can cause fatal cardiovascular collapse; anesthetics exaggerate hypotensive and CNS depressant effects; metrizamide increases risk of seizures; compounds hypotensive effects of diuretics and other antihypertensive agents. Food: All tyramine-containing foods (aged cheeses, processed cheeses, sour cream, wine, champagne, beer, pickled herring, anchovies, caviar, shrimp, liver, dry sausage, figs, raisins, overripe bananas or avocados, chocolate, soy sauce, bean curd, yeast extracts, yogurt, papaya products, meat tenderizers, broad beans) may precipitate hypertensive crisis. Herbal: Ginseng, ephedra, ma huang, St. John's wort may precipitate hypertensive crisis.


Duration: Up to 2 wk. Metabolism: In liver.

Nursing Implications

Assessment & Drug Effects

  • Monitor for therapeutic effectiveness: May be apparent within 1 wk or less, but in some patients there may be a time lag of 3–4 wk before improvement occurs.
  • Monitor BP. Monitor for orthostatic hypotension by evaluating BP with patient recumbent and standing.
  • Check for peripheral edema daily and monitor weight several times weekly.
  • Note: Toxic symptoms from overdosage or from ingestion of contraindicated substances (e.g., foods high in tyramine) may occur within hours.
  • Monitor I&O and bowel elimination patterns.

Patient & Family Education

  • Make position changes slowly and in stages; lie down or sit down if faintness occurs.
  • Use caution when performing potentially hazardous activities.
  • Consult physician before self-medicating with OTC agents (e.g., cough, cold, hay fever, or diet medications).
  • Avoid alcohol and excessive caffeine-containing beverages and tryptophan and tyramine-containing foods including cheeses, yeast, meat extracts, smoked or pickled meat, poultry, or fish, fermented sausages, and overripe fruit.

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug

© 2006-2022 Last Updated On: 11/21/2022 (0)
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