TRANYLCYPROMINE

synthetic drug of the monoamine-oxidase inhibitor type, used to treat severe mental depression. Like other monoamine-oxidase inhibitor drugs, tranylcypromine prevents the enzymatic breakdown of norepinephrine, the brain-neurotransmitter substance concerned with emotional stimulation. It does so by inhibiting the enzyme monoamine oxidase (MAO), which normally breaks down norepinephrine at nerve endings. Tranylcypromine is administered orally. 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.