Effects of atenolol and diltiazem‐SR on exercise and pressure load in hypertensive patients

The effects of monotherapy with atenolol or diltiazem‐SR on blood pressure, 24‐h blood pressure (BP) load, and exercise capacity were tested in patients with mild to moderate (stages I and II) essential hypertension. After 3‐week single blind placebo therapy, patients with sitting diastolic blood pressure (SDBP) of 94‐114 mmHg were randomized to atenolol 50 mg/day (62 patients) or diltiazem‐SR 90 mg b.i.d. (60 patients) in a double‐blind parallel study. Depending on SDBP response, the dose was increased to 100 mg/day for atenolol and 180 mg b.i.d. for diltiazem‐SR. Twenty‐four‐hour ambulatory blood pressure measurements and exercise tolerance lest by the Bruce protocol were done at the end of placebo and active treatment. Compared with placebo, both atenolol and diltiazem‐SR significantly decreased heart rate (HR), sitting systolic blood pressure (SSBP), SDBP, ambulatory BP, BP load for waking and sleeping hours, area under the BP curve, rate‐pressure product (p < 0.001), and exercise time (NS). Atenolol exerted a greater effect on ambulatory BP, HR, rate‐pressure product, waking diastolic BP load, and area under the 24‐h BP curve. The drugs were well tolerated and caused no serious side effects necessitating discontinuation of treatment. These findings indicate that (1) monotherapy for hypertension with atenolol or diltiazem SR is effective and well tolerated, (2) it decreases the 24‐h BP load, (3) it does not interfere with exercise capacity.