Nardil is a potent inhibitor of monoamine oxidase. Because this enzyme is widely distributed throughout the body, diverse pharmacologic effects can be expected to occur. When they occur, such effects tend to be mild or moderate in severity (see below), often subside as treatment continues, and can be minimized by adjusting dosage; rarely is it necessary to institute counteracting measures or to discontinue Nardil.

Common side effects include:

• Dizziness, headache, drowsiness, sleep disturbances (including insomnia and hypersomnia), fatigue, weakness, tremors, twitching, myoclonic movements, hyperreflexia.
• Constipation, dry mouth, gastrointestinal disturbances, elevated serum transaminases (without accompanying signs and symptoms).
• Weight gain.
• Postural hypotension, edema.
• Sexual disturbances, eg, anorgasmia and ejaculatory disturbances and impotence.

Rare side effectsof Nardil:

• Jitteriness, palilalia, euphoria, nystagmus, paresthesias.
• Urinary retention.
• Hypernatremia.
• Pruritus, Skin rash, sweating.
• Blurred vision, glaucoma.

An uncommon withdrawal syndrome following abrupt withdrawal of Nardil has been infrequently reported. Signs and symptoms of this syndrome generally commence 24 to 72 hours after drug discontinuation and may range from vivid nightmares with agitation to frank psychosis and convulsions. This syndrome generally responds to reinstitution of low-dose Nardil therapy followed by cautious downward titration and discontinuation.