Effect of inhibition of converting enzyme by captopril on arterial pressure, renin and aldosterone in essential hypertension

The response of arterial blood pressure, plasma renin activity (PRA) and plasma (PA) or urinary aldosterone (UA) concentrations to the administration of captopril, was studied in patients with established essential hypertension. Captopril was effective in lowering significantly the blood pressure (189.4/111.2 +/- 23.9/9.7 to 163.4/98.1 +/- 20.7/8.6 mmHg. mean +/- SD, p less than 0.01/0.001). Normal arterial blood pressure values (140.4/86.5 +/- 20.7/10.8 mmHg, were achieved by the addition of hydrochlorothiazide. Captopril administration was followed by a decrease in PA and in UA and an increase in PRA, suggesting the inhibition of angiotensin II formation. Captopril attenuated hypokalemia and hyperaldosteronism produced by the simultaneous administration of hydrochlorothiazide.