Effects of Nifedipine Treatment on the Renin-Angiotensin-Aldosterone Axis

Nifedipine is a commonly used agent in treating hypertension and angina because of its vasodilator properties. An inhibitory role of nifedipine on aldosterone (Aldo) biosynthesis has been documented in in vitro studies. This study was designed to examine the impact of a sustained release nifedipine formulation on Aldo biosynthesis and its clinical consequences. Early and late effects of nifedipine on Aldo, PRA, and Aldo/PRA ratio levels were studied in a single blind, placebo-controlled, 10-day pilot study. Ten normotensive subjects and 10 patients with hypertension were studied. Blood samples for the measurement of Aldo and PRA were obtained at 2-h intervals for 10 h on a control day and on days 1 and 8 of nifedipine treatment for the determination of baseline, early, and late values. Placebo was administered at 0800 h on the first and second days of the study, whereas nifedipine (60 mg/day) was given for the following 8 days. The Aldo/PRA ratio was used as a sensitive indirect index of the responsivenes...