Antihypertensive efficacy and effects of nitrendipine on cardiac and renal hemodynamics in mild to moderate hypertensive patients: randomized controlled trial versus hydrochlorothiazide.

Abstract

In this study antihypertensive efficacy, safety, and the effects of short-term nitrendipine administration on central and renal hemodynamics were evaluated in mild to moderate hypertensives. Our final goal was to ascertain whether the reduction in blood pressure induced by nitrendipine treatment was associated with maintained renal function. After a run-in period with placebo, 26 hypertensives without cardiac or renal disease were randomly assigned to a double-blind 8-week controlled trial with nitrendipine (N) 20 mg once a day (13 pts) or hydrochlorothiazide (HCT) 25 mg once a day (13 pts). Renal hemodynamic measurements included effective renal plasma flow (ERPF) and glomerular filtration rate (GFR) by radionuclide study using I-131 hippuran and Tc-99m, according to the methods described by Schlegel and Gates, respectively. Effective renal blood flow [ERBF = ERPF/(1-Ht)], filtration fraction (FF = GFR/ERPF), and renal vascular resistance (RVR = MBP x 80/ERBF) were also calculated. Other hemodynamic measurements included cardiac index (CI), left ventricular (LV) ejection fraction (EF), and total peripheral resistance (TPR) measured by the first-pass radionuclide angiography technique. At the end of N or HCT administration significant decreases (p less than 0.001) in SBP, DBP, and MBP vs. baseline values were observed in both hypertensive groups. In the N group a significant decrease (p less than 0.01) in TPR and RVR, and significant increases (p less than 0.05) in CI, ERPF, and ERBF were observed. In the HCT group a significant decrease (p less than 0.05) in RVR was found without significant changes in other hemodynamic parameters. No important side effects were observed with either therapy. In conclusion, nitrendipine was effective in reducting blood pressure in mild to moderate hypertensive patients and exerted favorable effects on cardiac and renal function.