Human metabolism of cyproheptadine.

Gas-liquid chromatographic and mass, nuclear magnetic resonance, and infrared spectrometric techniques were utilized to identify some of the metabolites of cyproheptadine in the urine of human subjects who had ingested radiolabeled drug. Aromatic ring hydroxylation (followed by glucuronide conjugation), N-demethylation, and heterocyclic ring oxidation were shown to occur in man. The principal metabolite, however, was identified tentatively as a quaternary ammonium, glucuronide-like conjugate of cyproheptadine. No evidence was found for metabolic changes at the tricyclic ethylene bridge in this species.