Sustained-release verapamil and nifedipine in exercise-induced angina pectoris.

In a randomised, double-blind, crossover study of oral sustained-release verapamil 360 mg o.d. ('SR-verapamil') and oral nifedipine 20 mg t.d.s. in 19 patients with chronic stable angina pectoris, significantly greater improvement from baseline was seen with SR-verapamil than with nifedipine. Mean exercise duration was 380 +/- 108 s with SR-verapamil and 343 +/- 130 s with nifedipine (P less than 0.05); mean time to onset of angina was 326 +/- 79 s with SR-verapamil and 239 +/- 79 s with nifedipine (P less than 0.01); median time to 1 mm ST depression was 252 s (range 114-579) with SR-verapamil and 182 s (range 84-582) with nifedipine (P less than 0.01); mean ST depression at maximum exercise was 1.65 +/- 0.56 mm with SR-verapamil and 2.17 +/- 0.98 mm with nifedipine (P less than 0.05). Ambulatory ECG recordings indicated a trend in favour of SR-verapamil (median ST-time integral 0.00 [range 0-24.16] mm h-1 with SR-verapamil, 1.15 [range 0-12.50] mm h-1 with nifedipine, not significant). Median glyceryl trinitrate consumption was significantly lower (P less than 0.05) with SR-verapamil (0.21; range 0-1.25 per day) than with nifedipine (0.31; range 0-1.32 per day), but there was no significant difference between angina attack frequency. Adverse events were reported by two patients with SR-verapamil and nine with nifedipine. Once-daily sustained-release verapamil 360 mg has a significantly better effect on exercise tolerance than nifedipine 20 mg t.d.s. and also appears to be better-tolerated.