Improved exercise performance following single daily dose of atenolol in stable angina.

We administered atenolol to 10 patients with effort limiting angina pectoris. Doses of 50 mg, 100 mg and 200 mg provided significant improvement (P less than 0.05) in exercise tolerance tested 24 hours after the drug was given. Twenty-five milligrams was not significantly better than placebo in increasing work tolerance. Side effects were minimal, and treatment could be continued throughout the study. The beta-blocker atenolol is an effective drug in the treatment of exercise-induced angina.