Postmarketing survey of the effects of an atenolol/chlorthalidone combination in the treatment of hypertension.

A large-scale postmarketing survey was conducted in the United States to evaluate the antihypertensive efficacy and safety of a combination of 50 mg of the long-acting cardioselective beta-blocker atenolol and 25 mg of the monosulfonamyl diuretic chlorthalidone. The program included 28,585 patients (of whom 26,892 provided sufficient information by questionnaire for an assessment of efficacy and race), and the participation of 7,009 primary-care physicians. After four weeks of treatment, patients had a mean reduction in systolic blood pressure of 21 mmHg and in diastolic blood pressure of 13 mmHg. The magnitude of these reductions did not differ appreciably with respect to age, sex, race, or previous therapy. Diastolic blood pressure was reduced by at least 11 mmHg in 55% of patients and systolic blood pressure was reduced by at least 16 mmHg in 59% of patients. Physicians' assessments indicated that 86% of patients achieved satisfactory control of blood pressure by the end of the study. The physicians' global assessment of the effectiveness of treatment indicated that the combination was better than previous therapy in 82% of patients; 91% of physicians planned to continue treatment with the fixed combination. There were no adverse experiences that had not been reported previously, and only dizziness exceeded an incidence of 1%. It was concluded that the fixed combination provides added blood pressure control and the convenience of a simplified once-daily regimen without added side effects, regardless of age, sex, race, or prior antihypertensive therapy.