In an open crossover comparison of propranolol and nitrendipine, 19 patients with hypertension received 40 to 160 mg propranolol and 5 to 20 mg nitrendipine twice a day. Mean (+/- SD) predose supine blood pressure fell from 145/98 +/- 11/7 to 132/88 +/- 12/8 mm Hg with propranolol and to 135/92 +/- 11/9 mm Hg with nitrendipine. Resting heart rate was reduced by propranolol but was unchanged 12 hours after nitrendipine dosing. Neither propranolol nor nitrendipine altered plasma glucose or insulin after oral glucose. Propranolol significantly increased fasting triglyceride levels and reduced high-density lipoprotein cholesterol levels, but nitrendipine induced no change. Propranolol reduced and nitrendipine increased plasma renin activity after exercise. Peak plasma nitrendipine levels were dose proportional and occurred at 1 to 2 hours after dosing, whereas peak blood pressure reductions occurred 4 hours after the last dose of nitrendipine and were associated with mean increases in heart rate. Nitrendipine is almost equivalent in hypotensive effect to propranolol, but nitrendipine increases plasma renin activity after exertion and may produce transient tachycardia. However, nitrendipine does not cause unwanted metabolic effects.