ISRADIPINE VERSUS CAPTOPRIL IN PATIENTS WITH ESSENTIAL-HYPERTENSION

We conducted a double-blind, crossover study comparing the antihyperte nsive effects of isradipine versus captopril in patients with essentia l hypertension. Seventeen patients (8 men, 9 women; 6 whites, 11 black s) completed both phases of the study, which consisted of two 5-week t reatment periods separated by 2 weeks of placebo treatment. Each drug was randomly allocated to half the patients as the first drug and half as the second drug they received. Ambulatory blood pressure (BP) moni toring was carried out on the day before treatment and the last day of each active treatment. Both drugs were effective and well tolerated b ut isradipine was more effective overall than captopril in lowering BP (9.4% vs 3.9%, respectively; P < 0.02). Black patients had significan tly higher BP at baseline than white patients; furthermore, black pati ents responded better to isradipine than to captopril. White patients had a smaller decrease in blood pressure with both drugs than did blac k patients, but white patients still attained a lower diastolic BP wit h captopril than did black patients (88 +/- 2 mm Hg vs 96 +/- 9 mm Hg; P < 0.01). There was no correlation between the pretreatment plasma l evels of presser hormones (plasma renin activity, catecholamines, and arginine vasopressin) and the magnitude of BP response to either drug, but the decrease in BP in response to captopril correlated significan tly with the increase in plasma renin activity during treatment (r = - .84; P < 0.05). It appears that the greater overall response to isradi pine than to captopril was due to the fact that our study population w as predominantly black, as black patients had both more severe hyperte nsion at baseline than white patients and were less responsive to mono therapy with angiotensin-converting enzyme inhibitors.