This multicenter, randomized, double-blind, parallel group, placebo lead-in, placebo-controlled study compared the antianginal and anti-ischemic effects of once-daily bedtime dosing of controlled-onset extended-release (COER-24) verapamil to a once-daily morning dosing of amlodipine +/- atenolol in patients with chronic stable angina. A total of 551 patients with exercise-induced myocardial ischemia and evidence of coronary artery disease were randomized to a 4-week, forced-dose titration treatment period with (1) COER-24 verapamil 240 mg titrated to 480 mg at bedtime (n = 173), (2) amlodipine 5 mg titrated to 10 mg/day (n = 149), (3) amlodipine 5 mg (titrated to 10 mg) plus atenolol 50 mg/day in the A.M. (n = 154), or (4) placebo (n = 75). Treadmill exercise tolerance testing (standard Bruce protocol), and 48-hour ambulatory electrocardiographic (Holter) monitoring were performed at the end of placebo lead-in and double-blind treatment. Each active treatment significantly improved symptom-limited exercise duration and time to moderate angina (p < or = 0.01 vs placebo). For patients with baseline ischemia, amlodipine resulted in a statistically significant increase in total duration of ischemic episodes compared with placebo, whereas COER-24 verapamil and amlodipine plus atenolol resulted in statistically significant decreases compared with placebo and amlodipine. Heart rate at onset of ischemic episodes and ST product were also significantly increased with amlodipine (p < 0.05) compared with either COER-24 or amlodipine plus atenolol. COER-24 and amlodipine alone or in combination with atenolol improved exercise capacity in patients with angina pectoris. COER-24 verapamil monotherapy or amlodipine plus atenolol combination therapy were more effective than amlodipine monotherapy in decreasing ambulatory myocardial ischemia, especially during the hours of 6 A.M. to 12 noon.