Verapamil administered twice daily in stable angina pectoris.

To assess whether verapamil taken orally twice daily (bd) was as effective as four times daily (qd) in patients with angina a placebo controlled double blind crossover trial was conducted in 12 patients. Each patient was randomized to verapamil, 160 mg bd, 80 mg qd, or corresponding placebo, each for three weeks. Patients were assessed subjectively and by treadmill exercise test. On both verapamil regimens, patients had less angina with delayed onset of ST segment depression during exercise compared to placebo, without any differences between the two regimens. On bd verapamil, patients could increase their exercise capacity as much as on qd without any increase in adverse effects. Angina threshold during exercise was increased by both regimens with a slightly higher threshold on qd verapamil compared to bd. Therefore, administration of verapamil twice daily is effective in patients with stable angina pectoris, with a similar efficacy to taking verapamil four times daily without any increase in adverse effects.