Efficacy and safety of incremental doses of diltiazem for the treatment of stable angina pectoris

The safety and efficacy of incremental doses of diltiazem in treating angina pectoris were assessed in 20 patients with functional class II to III exertional angina. During an initial single-blind dose titration phase, diltiazem produced a dose-related improvement in anginal frequency and exercise capacity. Weekly anginal attacks were reduced to 7.5 ± 8.9, 5.6 ± 7.8 and 4.9 ± 7.3 on diltiazem, 120, 240 and 360 mg per day, respectively, as compared with 11.9 ± 8.7 on placebo (all p < 0.001). Treadmill time was significantly enhanced by high dose (360 mg per day) as compared with moderate dose (240 mg per day) diltiazem: 473 ± 149 versus 424 ± 146 seconds (p < 0.05). Time to ischemic ST segment depression was similarly changed: 344 ± 132 versus 298 ± 142 seconds (p < 0.05) by high dose as compared with moderate dose diltiazem.During a subsequent double-blind phase, high dose diltiazem significantly reduced weekly anginal frequency when compared with placebo: 3.1 ± 3.0 versus 9.3 ± 7.1 (p < 0.001); and increased treadmill exercise time: 508 ± 158 versus 418 ± 172 seconds on placebo (p < 0.05). Subjective and objective benefits of high dose diltiazem were sustained during a follow-up period of 6 months without major drug side effects