Merits of adding a beta blocker (acebutolol) to a diuretic (hydrochlorothiazide) in the treatment of hypertension.

In a double-blind crossover study, the antihypertensive effect of hydrochlorothiazide alone and in combination with the beta blocker acebutolol was assessed in 18 patients suffering from mild to moderate hypertension. After a placebo period, the patients were placed on hydrochlorothiazide alone for four weeks at a dose of 50 mg daily. Acebutolol was than gradually titrated into the regimen until the optimum dose was established. The average dose was 555 mg per day, with the usual optimum dose 200 mg b.i.d. The patients then entered the crossover portion of the trial during which patients received either hydrocholorothiazide with acebutolol or hydrochlorothiazide with placebo. Each treatment period lasted six weeks. Blood pressure and heart rate were significantly lower with the combination treatment than with hydrochlorothiazide alone. At the end of each treatment period, the mean diastolic blood pressure (erect) was 90.5 mm Hg with hydrochlorothiazide-acebutolol but remained above 100 mm Hg with the diuretic alone. Neither hydrochlorothiazide nor acebutolol produced any significant changes in plasma renin activity or plasma aldosterone. There were very few side effects and no reports of bradycardia.