The 24 h blood pressure responses of hypertensives to a once-a-day cilazapril regimen

Abstract

The efficacy of once-a-day cilazapril (a new long acting converting enzyme inhibitor) therapy for the 24 h control of hypertension and its effects on the renin-angiotensin axis were investigated. Twenty-four uncomplicated hypertensive patients whose sitting diastolic blood pressures remained within 94 to 114 mmHg after four weeks of placebo were randomly assigned on a double-blind basis to receive either continued placebo or cilazapril therapy at a single dose of 1.25, 2.5 or 5.0 mg/day for a further four weeks. At the end of weeks 4 and 8, systolic and diastolic blood pressures and heart rates were recorded, supine and standing, at 0, 2, 4, 6, 9, 12 and 24 h following a single dose of drug. At the same times, blood was withdrawn for determination of plasma renin activity and aldosterone. Supine and erect systolic and diastolic blood pressures were lowered to normotensive levels with an optimal response being achieved at a dose of 2.5 mg/day. Supine and erect heart rates were unchanged with respect to drug dosage, and the reflex increase in heart rate and diastolic blood pressure on changing from supine to erect posture was maintained in all groups. Maximum antihypertensive efficacy was from 2 to 6 h after drug ingestion. There were no changes in resting aldosterone, but plasma renin activity was increased at all drug dosages. A single 2.5 mg dose of cilazapril provides blood pressure control for a 24 h period. Cilazapril does not appear to interfere with the reflex autonomic responses to postural change.