title: The metabolism of DL-[14C]verapamil in man.
abstract: The metabolism of DL-verapamil in man was studied after oral administration of an aqueous solution of DL-[14C]verapamil. Between 67 and 71% of the 14C administered was excreted in the urine within 5 days. Verapamil was extensively metabolized; only 3--4% of the dose was excreted in the urine as unchanged drug. Cleavage of the C--N--C bond by N-'dealkylation, preferentially at the C-atom belonging to the shorter side chain, was the main metabolic step. Verapamil and its N-dealkylated metabolites were further metabolized by O-demethylation. Inasmuch as approximately 10 times more of the metabolites formed from the tertiary amine verapamil are secondary amines than are primary amines, it would seem that N-dealkylation of this tertiary amine proceeds at a much higher rate than the N-dealkylation of the secondary amine metabolites to primary amine metabolites.
mesh_terms: D000368:Aged; D001711:Biotransformation; D002852:Chromatography, Ion Exchange; D002855:Chromatography, Thin Layer; D006801:Humans; D008297:Male; D013058:Mass Spectrometry; D008875:Middle Aged; D014700:Verapamil / Q000378:metabolism* / Q000652:urine
chemical_list: D014700:Verapamil