Clinical Effects of Low-dose Captopril Plus a Thiazide Diuretic on Mild to Moderate Essential Hypertension: a Multicenter Double-blind Comparison with Propranolol. Captopril Research Group of Japan

A total of 270 patients with mild to moderate essential hypertension were evaluated in a multicenter double-blind randomized study that compared the effect of captopril plus a thiazide diuretic with that of propranolol plus a diuretic. All patients were previously uncontrolled with diuretics alone. Following a 4-week placebo control period, during which diuretic was not withdrawn, the patients were treated either with 37.5-75 mg/day of captopril (n = 133) or with 60-120 mg/day of propranolol (n = 137) for 12 weeks, the diuretic being continued in both groups. Blood pressure in both groups was significantly reduced after 2 weeks of treatment. Reduction in systolic but not diastolic blood pressure after 10 and 12 weeks of treatment was significantly greater in the captopril group than in the propranolol group (p less than 0.05). Treatment was considered to be effective in 77% of the captopril patients and in 61% of the propranolol group. The difference was significant (p less than 0.05). Side effects occurred in 6 of the 133 patients (4.5%) treated with captopril and in 16 of the 137 patients (11.7%) treated with propranolol. The difference between the two groups was significant (p less than 0.05). There were few significant changes in laboratory data in either group. The serious side effects previously reported with higher doses of captopril were not observed. The results indicate that low-dose captopril plus a diuretic is more efficacious than propranolol plus a diuretic in mild to moderate essential hypertension previously uncontrolled with a diuretic alone.