Atenolol once‐daily in hypertension.

1 The effect of atenolol, a cardioselective beta adrenoceptor antagonist, was studied in a double-blind crossover trial in twenty-one carefully selected hypertensive outpatients. Each patient received atenolol (50 mg/day, 100 mg/day, 200 mg/day) and placebo according to a randomized sequence in a once-daily dose. Wash-out periods on a matching placebo were included between the treatment periods. 2 The effect of lying, standing and post-exercise blood pressure of atenolol 50 mg once-daily was not significantly different from atenolol 100 or 200 mg once-daily. The reduction in lying and standing blood pressure was approximately 23/16 and 22/18 mm Hg from levels at the end of a run-in period on matching placebo of 167/108 and 162/112 mm Hg respectively. 3 The study shows that atenolol is an effective hypotensive agent in a once-daily dose.