Efficacy of a low fixed-dose combination of penbutolol with piretanide in the treatment of mild to moderate hypertension: a double-blind study against placebo.

A double-blind crossover study was carried out in 20 patients with mild to moderate essential hypertension to assess the efficacy and tolerability of a low fixed-dose combination containing 20 mg penbutolol (a beta-blocking agent) and 3 mg piretanide (a diuretic) in comparison to placebo over a period of 4 weeks. Active drug treatment in the 20 patients studied was preceded by a 1-week period of placebo. The results showed that there was an effective significant reduction in systolic and diastolic blood pressure compared with initial levels in the fixed-dose combination group, when compared to the placebo group, both at rest, during maximal ergometric and isometric work load, and also in the diurnal blood pressure profile over 24 hours. Pulse rate also decreased in the combination group. The biochemical, haematological and urinary parameters showed no clinically relevant changes in either group during the entire study period. Minor side-effects definitely or probably associated with the treatment were observed in both groups but were generally mild and did not interfere with treatment. No patient withdrew prematurely from the trial.