[Acute effect of nifedipine on arterial pressure and the renin-angiotensin system in healthy subjects and hypertensives].

The acute effects of nifedipine (20 mg capsules) on the blood pressure and renin-angiotensine system were studied in 108 subjects, 25 normotensives, 51 borderline hypertensives and 33 permanent essential hypertensives. The fall in mean blood pressure (MBP) was rapid (less than 30 minutes) and significant in all groups; the amplitude the hypotensive response expressed as a percentage of the basal MBP was directly related to the basal MBP value (r = 0.54, p less than 0.001). The amplitude of the response correlated with the control plasma renin activity only the group with permanent hypertension (r = - 0.40, p less than 0.025). The fall in blood pressure and the reflex sympathetic stimulation induced by nifedipine were not associated with an increased plasma renin activity. The plasma aldosterone concentrations varied only in the group of permanent hypertensive patients after nifedipine ( - 4 +/- 1 ng/dl, p less than 0.01).