Hemodynamic comparison of two nifedipine formulations in patients with essential hypertension

The hemodynamic and humoral effects and trough-to-peak 24-hour blood pressure responses of 2 nifedipine formulations, capsules and continuous-release once-daily formulation tablets, were evaluated in 10 patients with mild to moderate essential hypertension. Both formulations reduced mean arterial pressure similarly from 120 +/- 3 (baseline) to 107 +/- 2 (p less than 0.005) and 105 +/- 2 mm Hg (p less than 0.005) and total peripheral resistance index from 65 +/- 9 (baseline) to 47 +/- 4 (p less than 0.05) and 45 +/- 3 U/m2 (p less than 0.05), respectively. Renal, splanchnic and total forearm (including skin and skeletal muscle) blood flows were maintained or even increased slightly associated with reductions in regional vascular resistances. Decreases in renal, total forearm and skeletal muscle resistances were significant (p less than 0.05) with the capsules, but the decrease was only significant in renal resistance with the long-acting tablets. Intravascular volume did not expand with reduction in arterial pressure. This antihypertensive effect was not related to baseline plasma renin activity levels or age. Nifedipine tablets provided a better control of mean arterial pressure (66%) than did capsules (44%).