Influence of food on the bioavailability of a sustained-release verapamil preparation.

Abstract

The effects of food on the bioavailability of a sustained-release (SR) formulation of verapamil (SR-verapamil; Isoptin SR) were determined in an open, three-way single-dose study involving 12 volunteers receiving (in randomized order) the SR preparation (1 X 240 mg) either fasting or with food and a conventional formulation of verapamil (3 X 80 mg) fasting. Compared with the conventional formulation, SR-verapamil had a reduced Cmax, prolonged tmax, and unchanged t1/2, consistent with its SR formulation. The AUC was 80% of the conventional preparation. Concomitant food administration significantly prolonged the tmax of SR-verapamil from 7.3 +/- 3.4 to 11.7 +/- 6.3 h, but had little effect on Cmax, t1/2, or AUC. Similar results were obtained with the metabolite, norverapamil. Food administration also had little effect on the blood pressure and ECG effects of SR-verapamil. Cautions regarding taking this preparation with food therefore appear to be unnecessary.