Effects of Slow-release Nifedipine on Hemodynamics and Pharmacokinetics in Elderly Hypertensives.

Ten elderly hypertensives (4 men, 6 women) were studied before and after 8-week administration of 20 mg/day slow-release nifedipine. Systemic and regional hemodynamic data were measured using a pulsed Doppler technique. Slow-release nifedipine reduced mean arterial pressure, while cardiac output remained unchanged, resulting in a decrease in total peripheral resistance. None of common carotid, vertebral, celiac, superior mesenteric, renal, or terminal aortic flow changed significantly before or after administration of slow-release nifedipine. Pharmacokinetic parameters were as follows: Cmax, 59.1 ng/ml; AUC, 288.2 ng hr/ml; Tmax, 3.4 hr; t1/2, 5.5 hr. There was a direct relationship between the concentration of slow-release nifedipine and its depressor effect. Slow-release nifedipine had no influence on humoral factors such as plasma renin activity, angiotensin II, aldosterone, atrial natriuretic peptide, noradrenaline or adrenaline. Slow-release nifedipine may provide desirable hemodynamic effects in elderly hypertensives.