Amphetamine is understood to inhibit monoamine oxidase, whereas the power of amphetamine and its metabolites to inhibit various P450 isozymes and various enzymes has not been adequately elucidated. In vitro experiments with human microsomes point out minimal inhibition of CYP2D6 by amphetamine and insignificant inhibition of CYP1A2, 2D6, and 3A4 by