Atenolol and three nonselective beta-blockers in hypertension.

The object of this study was to establish whether cardioselectivity of atenolol confers any advantage over noncardioselective beta-blockade in the treatment of hypertension. A dose of atenolol was established on the basis of morning mean systolic blood pressure (mean of 5 readings) in 27 long-standing hypertensive patients previously controlled on one of three nonselective beta-blockers: propranolol, oxprenolol, or pindolol. Most patients were also taking a diuretic. A crossover trial was then conducted of atenolol and the previous nonselective beta-blocker, each drug being given for 8 wk in randomized order. Other drugs were kept constant. At the end of each 8-wk period a morning test of blood pressure and pulse rate was done, an 11:30 A.M. blood sample was taken for estimation of drug concentration, and spirometry was performed. During the eighth week a glucose tolerance test, fasting lipids, and other biochemical and hematologic estimations were done. On a separate occasion a late morning study was done on the response of blood pressure and pulse rate to three kinds of stress: bicycle ergometer, mental arithmetic, and handgrip. At dosage levels of atenolol giving a mean resting systolic blood pressure equal to that during nonselective beta-blockade, diastolic levels on atenolol tended to be lower at rest and during the mental and handgrip forms of stress. Serum creatinine levels on atenolol were lower than during nonselective beta-blockade. Anti-dioxyribonucleic acid (DNA) titers remained normal in all patients. There was no difference in lung function. There was little difference in glucose and insulin levels during glucose tolerance tests in these patients, half of whom were diabetic. There were no serious side effects but there were a few surprising ones such as vivid dreams in three and muscle cramps in one patient.