A COMPARISON OF THE EFFECTS OF NIFEDIPINE AND VERAPAMIL ON EXERCISE PERFORMANCE IN PATIENTS WITH MILD-TO-MODERATE HYPERTENSION

Twenty-four patients completed a double-blind, randomized clinical trial comparing the effects of nifedipine GITS (N) and verapamil SR (V) on blood pressure (BP) control and exercise performance. After a 2-week placebo phase, all subjects had measurements of V-O2max, maximal workload, and endurance time. They were then randomized to either N (30 to 90 mg/day) or V (240 to 480 mg/ day) and retested when BPs had stabilized. At rest, N lowered systolic (S) BP by 12 mm Hg (P=.02 compared to baseline) and diastolic (D) BP by II mm Hg (P=.001). V lowered SBP by 8 mm Hg (P =.013) and DBP by II mm Hg (P=.002). Neither drug affected resting heart rate. V significantly decreased resting epinephrine (P=.05) and there was a tendency for V to reduce norepinephrine (P=.07) and dopamine (P=.08). N tended to increase plasma renin activity (P=.07). During graded cycle ergometry N, compared with placebo, significantly lowered DBP at all exercise levels (P=.011), but had no significant effect on heart rate (HR), SBP, or heart rate pressure product (HRPP). Pulse pressure (PP) was significantly increased (P=.045), which was most noticeable at high exercise levels. Compared with placebo, V caused a marked reduction of exercise HR (P<.001), which was more pronounced at high levels, SBP (P=.004), DBP (P=.004), mean arterial pressure (MAP) (P=.001), and HRPP (P<.001). V caused a significantly greater reduction in HR (P=.069), SBP (P=.013), MAP (P=.056), PP (P=.023), and HRPP (P<.001) than N. There were no differences in DBP reduction. At maximum exercise, N significantly increased plasma norepinephrine (P=.04). Neither drug affected V-O2max, exercise duration, or maximum workload. In summary, both N and V lowered resting SBP and DBP. During graded cycle ergometry, both drugs effectively lowered DBP, but only V lowered SBP, PP, and HRPP. V is the preferred drug for those who participate in vigorous activity.