The pharmacology of reversible monoamine oxidase inhibitors.

The older monoamine oxidase inhibitors (MAOIs) are mechanism-based, irreversible inhibitors of MAO; most inhibit both the A and B forms of MAO. Several of the drugs are hydrazine derivatives which have non-specific effects other than MAO inhibition. These properties convey disadvantages, which may be seen as serious, though infrequent, adverse events--the 'cheese effect', hepatotoxicity, amphetamine-like activity, orthostatic hypotension and anticholinergic effects. New, reversible MAOIs stem from a variety of chemical classes and are more specific in their effects, with relatively rapid onset of action, direct relationship between plasma concentration and pharmacological effect, and no prolonged carry-over phenomena.