[Changes in plasma renin activity induced by acute administration of nifedipine in hypertensive patients (author's transl)].

In the present study we assessed plasma renin activity (PRA) variations induced by Ca++ antagonist antihypertensive drug Nifedipine in 8 normoreninaemic or hyporeninaemic hypertensive patients. On two successive days three venous blood samples were sampled, two in clinostatic position and the last one 120 min later in orthostatic position; on the second day 20 mg of nifedipine were administered sublingually. Nifedipine increases significantly PRA after orthostatic position compared with starting conditions (p < 0.01) and compared with the values recorded without the drug at the same times (p < 0.01). Both systolic and diastolic blood pressure decreased 15 and 120 min after nifedipine administration while heart rate increased at the same times. Acute nifedipine administration augments PRA in hypertensive subjects; explanatory hypoteses are proposed.