Influence of acetylator phenotype on antidepressant effects of phenelzine.

Acetylator phenotype, determined by blood levels after sulphadimidine, was related to outcome in a controlled trial of phenelzine in patients with depression and mixed anxiety depression. Slow acetylators showed more improvement and greater phenelzine-placebo differences than did fast acetylators, at two, four and six weeks. A tendency towards faster acetylation was observed in subjects with previous increased alcohol intake. Acetylator phenotype was not related to other symptom, diagnostic or history data.