Acebutolol in hypertension--double-blind trial against placebo.

1. Eleven hypertensive patients were studied in a double-blind comparison of acebutolol, a beta-adrenoceptor blocker, and placebo. 2. Optimum dosage defined in an open assessment varied from 200--600 mg twice daily. 3. Blood pressure and pulse rate fell significantly while patients were lying, standing and after exercise. 4. Blood pressure remained as well controlled on each patient's optimum daily dose when taken once daily, and assessed 24 h post dose. 5. There was no correlation between blood pressure reduction and changes in heart rate. On once daily therapy while blood pressure remained unchanged at 24 h post dose there was a signficant reduction in beta-adrenoceptor blockade as measured by percentage reduction in exercise tachycardia. 6. There was no significant change in urinary catecholamine excretion or echocardiographically estimated cardiac output. 7. A correlation was found between the change in plasma renin activity (log transformed) and blood pressure reduction.