Monoamine oxidase is a complex enzyme system, widely distributed throughout the body.
Drugs that inhibit monoamine oxidase in the laboratory are associated with a number of clinical effects. Thus, it is unknown whether MAO inhibition per se, other pharmacologic actions, or an interaction of both is responsible for the clinical effects observed. All the currently employed MAO inhibitors are readily absorbed after oral administration. They are not given parenterally. These drugs produce maximal inhibition of MAO in biopsy samples from man within 5 to 10 days.