Efficacy of captopril and nifedipine in black and white patients with hypertensive crisis

Abstract

We examined the antihypertensive efficacy of: (1) sublingual-oral single doses of captopril (25 mg) and nifedipine-capsules (10 mg) in 9 + 9 white patients and in 9 + 8 black patients with hypertensive crisis; and (2) a single oral dose of the slow-acting preparation of nifedipine-retard (20 mg) in another 10 black patients. Blood pressure (BP) was assessed at 10 min intervals for 6 h after administration. After 6 h, the BP falls induced by these drugs were still significantly lower than the baseline placebo values. Hypotensive effect of nifedipine-capsules was established more rapidly than that of captopril in both white and black patients, and of nifedipine-retard in black patients. Considering the area under the curve of BP values during the 6-h treatment, the overall hypotensive effect of nifedipine-capsules was similar to captopril in white patients, but significantly more pronounced than captopril and nifedipine-retard in black patients. In white patients similar maximal drops of BP (mean ± s.e.m.) were obtained with nifedipine-capsules (71 ± 4/52 ± 4 mm Hg) and with captopril (69 ± 4/50 ± 3 mm Hg). In black patients the maximal drop of BP of nifedipine-capsules (70 ± 4/52 ± 4 mm Hg) was greater (P < 0.02) than that of captopril (48 ± 4/32 ± 3 mm hg) but similar to that of nifedipine-retard (71 ± 4/49 ± 4 mm hg). however, in contrast to nifedipine-capsules and captopril, nifedipine-retard produced a slower drop in bp. the time of peak drop in bp of both nifedipine-capsules and captopril occurred within the first 2 h whereas with nifedipine-retard it occurred only between 4 and 6 h after administration. fewer patients reported side effects with nifedipine-retard as compared with the other two preparations. we conclude that single doses of captopril and nifedipine reduces bp for at least 6 h in both white and black patients with hypertensive crisis, but nifedipine is more potent than captopril in black patients. the slow release form of nifedipine-retard effectively and safely lowers bp while achieving a rapid enough effect without the critical rapid falls in bp that occur with nifedipine-capsules.