The Effects of Nicardipine on Sodium and Calcium Metabolism in Hypertensive Patients: A Chronic Study

Abstract

There is evidence in the literature that calcium entry blockers are able to affect calcium-dependent hormone secretion and therefore can influence sodium and calcium metabolism. We have studied in 18 mild to moderate hypertensives (27-65 yrs) the effects of chronic treatment with nicardipine, a dihydropyridine derivative, vs placebo on: 1) renin-angiotensin-aldosterone axis; 2) parathyroid hormone and calcium metabolism; 3) daily sodium and calcium urinary excretion. After a 2-week placebo wash-out when any antihypertensive treatment was withdrawn, patients were kept on a well balanced normocaloric diet without salt intake restriction. Blood pressure, plasma renin and serum aldosterone after a 1-hour standardized walk, serum PTH, serum and 24-hour urinary Na, K, Ca, P, Mg were measured. Thereafter patients were randomly and blindly given nicardipine 20 mg tid or placebo tablet tid for 2 months. At the end of this period the same measurements were repeated. Blood pressure significantly dropped during nicardipine (from 165/96 +/- 19/9 vs 150/88 +/- 16/9 mm Hg P less than .05) without change in heart rate. No change was observed on placebo. Plasma renin, serum aldosterone, serum parathyroid hormone and serum and urinary electrolytes did not change during active and placebo treatment. The results of this study suggest that chronic nicardipine does not affect hormone secretion.