Three recently concluded large randomized clinical trials have compared the preventive effects of
diuretic agents and beta-blockers in the treatment of approximately 22,000 subjects with
hypertension. In the Medical Research Council trial,
bendrofluazide (10 mg daily) was compared with a dose of
propranolol (as much as 240 mg daily), a nonselective beta-blocker without intrinsic
sympathomimetic activity. Two selective beta-blockers,
atenolol (100 mg daily) and
metoprolol (200 mg daily), were compared with
bendrofluazide (5-10 mg daily) and
hydrochlorothiazide (50-100 mg daily) in the
Heart Attack Primary Prevention in
Hypertension trial. In the International Prospective Primary Prevention Study in
Hypertension, 160 mg of slow-release
oxprenolol, a beta-blocker with intrinsic
sympathomimetic activity, was compared with a
diuretic-based regimen not containing beta-blockers. In each trial, similar reductions in mean diastolic blood pressure were achieved with
diuretic and beta-blocker treatment that lasted for several years. All-cause mortality and fatal and nonfatal
stroke and coronary event rates were also similar in the treatment groups. Thus, it appears that beta-blockers are as effective as
diuretic agents in improving survival and in preventing major morbid events. Regarding cigarette smoking and
stroke incidence, observations based on post hoc subgroup analyses of the Medical Research Council trial were not supported by subgroup findings in the
Heart Attack Primary Prevention in
Hypertension and the International Prospective Primary Prevention Study in
Hypertension trials, and these observations should not form the basis for any treatment recommendations.