Comparison of the pharmacokinetics of glipizide and glibenclamide in man.

Four subjects received 5 mg 14C-glipizide orally, 3 subjects 1 mg intravenously and 2 subjects 5 mg 14C-glibenclamide orally. Plasma levels of radioactivity, and urinary and faecal excretion were measured. For both drugs the disappearance of radioactivity from plasma followed complex kinetics and the apparent half-lives increased steadily with time. The two sulfonylureas were extensively metabolized and were excreted in the urine as hydroxylated or conjugated metabolites. The effects of both drugs on blood glucose and immunoreactive insulin were comparable. The findings are compared with other published results.