NIFEDIPINE-RETARD VERSUS NIFEDIPINE-CAPSULES FOR THE THERAPY OF HYPERTENSIVE CRISIS IN BLACK PATIENTS

In a randomized parallel-group placebo-controlled study, we compared t he short-term hypotensive efficacy and the safety of a single administ ration of nifedipine-retard (20-mg tablets) with that of two administr ations 6 h apart of nifedipine capsules (10 mg) in 10 and 11 black pat ients, respectively, with acute severe hypertension. Both groups had s imilar pretreatment blood-pressure (BP) values. Blood pressure was rec orded at 10-min intervals for 12 h by using an automated device. In th e first 3 h of treatment, nifedipine capsules induced a faster and gre ater hypotensive effect than nifedipine retard, which was associated w ith an increase in heart rate. At 2 h after treatment, nifedipine caps ules decreased BP to levels (159 +/- 5/105 +/- 3 mm Hg) that were sign ificantly lower than those reached by nifedipine-retard (175 +/- 4/118 +/- 4 mm Hg; p < 0.05). Both preparations induced a similar maximal B P decrease of similar to 30% of the placebo values, but the peak decre ase of BP occurred significantly later with nifedipine-retard (283 +/- 31 min after administration) than with nifedipine capsules (100 +/- 1 4 min; p < 0.01). Four hours after administration, the hypotensive eff ect of nifedipine capsules was blunted, and a second administration wa s necessary, whereas nifedipine-retard reduced BP slowly and continuou sly for less than or equal to 12 h and more smoothly. Flush and headac he were more frequently found with nifedipine capsules. We conclude th at in black patients with hypertensive crisis, nifedipine capsules pro duce an abrupt decrease in BP that may be potentially harmful. Thus fo r patients suitable for treatment with nifedipine, nifedipine-retard i s preferable because it effectively reduces BP for greater than or equ al to 12 h while achieving a rapid enough effect without critical shor t-term decreases in BP.