Antidepressant potentiation of 5-hydroxytryptophan by L-deprenil in affective illness.

In an open trial study, L-Deprenil, an irreversible selective MAO-B inhibitor without 'chesse effect' was given to 14 patients with unipolar and bipolar depression receiving L-5-Hydroxytryptophan (L-5-HTP) and benzerazide. Ten out of 14 patients showed a good response to the combination of drugs and a correlation was found between the degree of platelet MAO inhibition and clinical response. In a double-blind controlled study, 18 affectively ill patients were randomly allocated to L-Deprenil plus L-5-HTP and benzerazide, 21 patients were treated with L-5-HTP and benzerazide and 19 patients with placebo only. Patients treated with the combination of L-Deprenil and L-5-HTP showed a significantly greater clinical improvement than placebo patients but this was not the case for patients treated with 5-HTP alone. A positive relationship was demonstrated between mood improvement and degree of platelet MAO inhibition in patients treated with L-Deprenil.