Acute and Chronic Effects of a New Calcium Inhibitor, Nicardipine-on Renal Hemodynamics in Hypertension

Renal hemodynamics and natriuresis were studied in 10 hypertensive patients without renal failure, 2 and 4 h after oral intake of 30 mg nicardipine; then, nicardipine was given at a dose of 30 mg three times a day and the hemodynamic study was repeated on the 6th day (2 h after the morning dose). The first dose of nicardipine produced an increase in renal blood flow (from 888 ± 45 to 999 ± 59 ml/min 1.73 m, p < 0.01) and a decrease in renal vascular resistances (from 0.16 ± 0.01 to 0.12 ± 0.01 arbitrary unit, p < 0.05). Glomerular filtration rate did not change and the decrease in filtration fraction was not significant. Sodium excretion increased markedly during the first 2 h (from 0.17 ± 0.04 to 0.29 ± 0.06 mmol/min, p < 0.05). On the 6th day renal vascular resistances and filtration fraction remained lowered whereas glomerular filtration rate was unchanged. Nicardipine did not produce any significant alteration in plasma renin activity and plasma aldosterone after acute or chronic administration. These results confirm the potent renal vasodilatory effect of nicardipine; glomerular filtration rate was not significantly altered whereas renal blood flow and filtration fraction returned to normal levels. An early and transcient natriuretic effect was observed after the first dose of nicardipine, and body weight showed a significant decrease during the study indicating that no sodium retention was induced by nicardipine.