Studies on the antihypertensive effect of single doses of the angiotensin converting enzyme inhibitor ramipril (HOE 498) in man.

The time course of the blood pressure lowering effect and the dose-response relationship of the new angiotensin converting enzyme inhibitor ramipril (HOE 498) were studied in 8 patients, with essential hypertension. As compared with placebo, a single oral dose of 2.5 mg ramipril lowered systolic and diastolic blood pressure. The antihypertensive action of single oral doses of 5, 7.5 and 10 mg ramipril was more pronounced. No change in heart rate occurred. Angiotensin converting enzyme activity was suppressed after all doses of ramipril studied. Plasma renin activity increased after 2.5 mg and 5 mg ramipril. Plasma aldosterone was not affected by 2.5 mg, but it fell after 5 mg ramipril. Thus, ramipril produced prolonged inhibition (more than 12 hours) of angiotensin converting enzyme activity and lowered blood pressure in patients with essential hypertension.