Comparative potency of atenolol and propranolol as beta-adrenergic blocking agents in man

The comparative potency of two beta-blockers, propranolol and atenolol, in the inhibition of exercise tachycardia and isoproterenol-tachycardia has been studied in two groups of hypertensive patients, using oral doses which were increased weekly. A linear correlation was observed between the reduction in exercise tachycardia and the dose of each drug, up to a daily dose of propranolol 480 mg and atenolol 600 mg. Propranolol was slightly (0.7/1) more potent in decreasing maximal exercise tachycardia than atenolol when tested in low doses (below 100 mg); at higher doses (480 mg) no differences were found. However, atenolol was 10 times less potent than propranolol in blocking isoprenaline-induced tachycardia, which seems to be related to the cardioselectivity of atenolol.