Double-blind comparison between propranolol and bendroflumethiazide in captopril-treated resistant hypertensive...

In a double-blind crossover trial, 15 captopril (daily dose 600 mg) treated patients received in addition to the converting enzyme inhibitor, placebo, propranolol (240 mg), or bendroflumethiazide (7.5 mg). Propranolol produced an additional hypotensive effect, while pulse rate slowed, indicating effective beta-adrenoceptor blockade. Plasma renin activity decreased, but the hypotensive effect of propranolol was not accompanied by changes in the plasma angiotensin II and aldosterone levels or in the urinary aldosterone excretion. Also bendroflumethiazide lowered blood pressure, while body weight decreased slightly. During captopril-bendroflumethiazide treatment, serum sodium and potassium decreased while the plasma renin-angiotensin-aldosterone system was stimulated. In these captopril-treated patients, the hypotensive response to bendroflumethiazide tended to be somewhat larger than the response to propranolol, but the difference was small and statistically not significant.