Bopindolol in the treatment of moderate hypertension: a dose-response study

To determine the optimal antihypertensive dose of bopindolol, we performed a randomized double-blind study in parallel groups. After 15 days of placebo single-blind, 115 hypertensive patients received daily for 28 days one of 4 doses: 0 mg (placebo), 0.5 mg, 1.0 mg, 2.0 mg. The reduction of supine diastolic blood pressure (BP) did not exhibit the pattern of a dose-effect relationship. The effect of 0.5 mg belonged to the plateau of the dose-effect curve (P = 0.1, analysis of variance). The reduction of heart rate (HR) followed a typical dose-effect curve, with a plateau beginning with 1 mg (P = 0.02). A trend toward an increase in the incidence of side-effects with dosage was observed (P = 0.3). Thus, the optimal antihypertensive dose may be 0.5 mg or less. Previous studies not using parallel randomized groups suggested an antihypertensive dose ranging from 2 to 4 mg. This study confirms that the dose-effect curves of beta blockers on HR and BP are dissociated. The dose-effect curve of HR seems unsuitable for assessing the optimal antihypertensive dose of a beta blocker.