Comparison of captopril and hydrochlorothiazide alone and in combination in mild to moderate essential hypertension.

1 A placebo-controlled, randomised double-blind comparison of captopril 25 mg three times a day, hydrochlorothiazide 15 mg three times a day, and the combination was conducted in 207 patients with essential hypertension with supine diastolic blood pressures of 92-110 mm Hg. Significant decreases in blood pressure were seen in all three groups; the magnitude of decrease seen with captopril and hydrochlorothiazide was similar, while the combination produced an additive response greater (p less than 0.001) than captopril or hydrochlorothiazide alone. 2 The major side effect reported was a rash in fewer than 6% of patients taking captopril alone or in combination. Loss of taste or proteinuria was not observed. 3 The addition of captopril of hydrochlorothiazide blunted the hypokalaemia and hyperuricaemia observed with hydrochlorothiazide alone in addition to its antihypertensive synergy. These observations indicate that this relatively low dose of captopril is safe and efficacious in the treatment of mild to moderate hypertension alone and particularly when combined with a thiazide diuretic.