Disposition and hypoglycaemic action of glipizide in diabetic patients given a single dose of nifedipine

Six well controlled Type 2 diabetics who had received glipizide therapy ranging from 5 mg to 30 mg daily for at least the previous 2 months were studied. On Days 1 and 15 nifedipine 20 mg or placebo respectively were given in a random crossover design after an overnight fast and with the morning dose of glipizide. Nifedipine did not influence the disposition of glipizide since there was no significant alteration in the maximum concentration, time to peak plasma concentration, elimination half-life or area under the curve. Neither did it have a major effect on plasma glucose or insulin although there was an early preprandial decrease in insulin level which reached significance at 1 h only (22.66 v 18.50 mIU/l).