Efficacy of a fixed-dose combination of 40 mg penbutolol with 6 mg piretanide in the treatment of mild to moderate hypertension: a double-blind study against placebo.

The antihypertensive efficacy and tolerability of a fixed-dose combination containing 40 mg penbutolol (a beta-blocking agent) and 6 mg piretanide (a diuretic) in comparison to placebo was investigated in a double-blind, crossover study in 20 patients with mild to moderate essential hypertension. After a 1-week period on placebo, patients were allocated at random to receive 1 tablet daily for 4 weeks of either the combination preparation or placebo and were then crossed over to the alternative medication for a further 4 weeks. The reduction in systolic and diastolic blood pressure both at rest, during maximal ergometric exercise and isometric word load, and also in the diurnal blood pressure profile over 24 hours was significantly greater in the group treated with the fixed-dose combination than in the placebo group. Pulse rate was also decreased to a greater extent. Mean diastolic blood pressure before exercise was reduced to normal (85.5 mmHg) after 4-weeks' treatment with the fixed-dose combination. Biochemical, haematological and urinary parameters showed no clinically relevant changes after either treatment. One patient complained of transient dizziness during treatment with the fixed-dose combination. No patient withdrew prematurely from the study because of side-effects.