COMPARATIVE EFFECTS ON BLOOD-PRESSURE AND REGIONAL HEMODYNAMICS OF NICARDIPINE AND CAPTOPRIL

This randomized, double-blind, crossover study was aimed at detecting efficacy differences in blood pressure control and peripheral circulation in cerebral aortic and femoral districts of slow-release nicardipine, 40 mg, and captopril, 50 mg, given twice daily to 20 primary hypertensive patients (9 male, 11 female; age range 33-60 years) for a period of 4 weeks for each treatment. Blood flow velocities in the aorta, common carotid artery, internal carotid artery, middle cerebral artery, and common femoral artery were noninvasively measured using a 2.0 or 5-MHz Doppler probe. Systolic blood pressure fall was similar with nicardipine (from 156 +/- 12 to 139 +/- 8 mm Hg, p < 0.001) and captopril (from 158 +/- 13 to 146 +/- 13 mm Hg, p < 0.001) while significant efficacy difference (p < 0.005) in diastolic pressure control was detected (from 104 +/- 6 to 91 +/- 8 mm Hg, p < 0.001 with nicardipine and from 102 +/- 6 to 98 +/- 7 mm Hg with captopril). Regarding regional hemodynamics, nicardipine increased (from 119 +/- 24 to 133 +/- 27 cm/s), and captopril did not affect systolic velocity in the aorta (difference between final data, p < 0.03). In the common carotid artery systolic velocity was increased solely by nicardipine. No significant changes were detected in the other vessels explored. These results indicate that the calcium entry blocker nicardipine affected more markedly than the angiotensin-converting enzyme inhibitor captopril diastolic blood pressure and blood flow velocity in the aorta and in the common carotid artery, probably as a result of more pronounced vasodilation and afterload reduction with consequent improvement of systolic function, as well as a slight reflex increase in heart rate. Despite the marked pressure reduction, blood flow velocity in the brain circulation was preserved on both drugs, since all patients had normal function of cerebral vasomotor regulation capacity.