ISOCARBOXAZID

antidepressant drug of the monoamine-oxidase inhibitor type, introduced into medicine about 1960 and used to treat moderate to severe mental depression. Like other monoamine-oxidase inhibitor drugs, it prevents the enzymatic breakdown of norepinephrine, the brain-neurotransmitter substance concerned with emotional stimulation. Isocarboxazid is administered orally and is readily absorbed from the stomach. The onset of action is delayed, the effects of the drug developing slowly over the first two weeks of therapy. As with other monoamine-oxidase inhibitor drugs, liver damage is a possible side effect.