BIOCHEMICAL MEASURE OF MONO-AMINE OXIDASE TYPE-A AND TYPE-B INHIBITOR EFFECTS IN MAN

A method is described for the measurement of the effects of monoamine oxidase inhibitors (MAOI's) in human plasma. The procedure was used to estimate the levels of pargyline and clorgyline in plasma from patients with affective disorders. The results indicate that after an oral dose, pargyline is rapidly absorbed into the blood, reaches a maximum level in approximately 1 hr and has a half life of approximately 2 hr. After chronic administration, neither pargyline nor clorgyline attain steady state levels of MAO inhibiting potential which are higher than those seen 12 hr after a single dose of drug. A single 50 mg dose of pargyline causes greater than 90% inhibition of platelet MAO (in agreement with the observation that platelet MAO is MAO type B); this dose of pargyline does not significantly alter plasma amine oxidase. Clorgyline at the dose used (20 mg) does not alter platelet MAO activity. © 1979.