Biochemical aspects of the pharmacology of moclobemide. The implications of animal studies.

Administration of moclobemide--a relatively short-acting, reversible inhibitor of monoamine oxidase-A (MAO-A)--to experimental animals potentiates the pressor responses to intravenously injected tyramine, but such effects are moderate, short-lived, and much less apparent when the tyramine is given orally. The ability of moclobemide to potentiate the pharmacological actions of amine substrates for MAO-A in in vitro preparations is very weak, unless the drug is 'activated' by prior incubation with the tissues. However, animal experiments, both in vitro and in vivo, can give realistic indications not only of the mode of action of inhibitors of MAO and any toxicity, but also, in the case of MAO inhibitors, of the chance of potentially life-threatening hypertensive crises following inadvertent ingestion of amine-containing food or medicaments. Animal tests may also reveal any influence MAOIs have on amines released from non-neuronal stores.