Beneficial effects of combined nifedipine and diltiazem for stable angina.

The antianginal effects of a combination of nifedipine and diltiazem were investigated in 6 patients with stable effort angina. Patients received one-week courses of successive treatment with 80 mg/day of nifedipine, 120 mg/day of nifedipine, then a combination of 120 mg/day of nifedipine and 120 mg/day of diltiazem, respectively. Patients then performed a symptom-limited treadmill exercise test at the end of each period of treatment. Mean exercise duration was 383 sec after receiving 80 mg/day of nifedipine 389 sec after receiving 120 mg/day of nifedipine and was then increased to 498 sec after receiving the nifedipine-diltiazem combination. The mean plasma nifedipine concentration at the end of one-week treatment increased from 134. 5 ng/ml during administration of 120 mg/day of nifedipine to 335.5 ng/ml during administration of the nifedipine-diltiazem combination. This study demonstrated that a combination of nifedipine and diltiazem is of value in the treatment of effort angina, partly because of an increase in the plasma nifedipine concentration as a result of the pharmacokinetic interaction between nifedipine and diltiazem.