Objective evaluation of three dose levels of diltiazem in patients with chronic stable angina.

Twenty-one patients with chronic stable angina were treated with the calcium antagonist diltiazem. Dose titration studies involving 180, 270 and 360 mg/day were conducted using a blinded objective protocol. Improvement in exercise tolerance was observed at all dose levels, but the best reduction of anginal attacks and glyceryl trinitrate consumption, enhancement of exercise capacity and improvement of objective ischemic variables were observed with the 360 mg/day dose. The mean exercise time to produce grade II angina on treadmill walking increased from 5.6 +/- 0.7 minutes on placebo to 7.9 +/- 0.8 minutes on diltiazem 180 mg/day (probability [p] less than 0.001), 8.0 +/- 0.8 minutes on 270 mg/day and 9.5 +/- 0.9 minutes on 360 mg/day (p less than 0.001 as compared with 270 mg/day). One patient was withdrawn at the 360 mg/day dosage because of pedal edema. The 24 hour Holter monitoring data confirmed the findings on exercise testing, and left ventricular function was not altered with any dose level. Diltiazem in doses ranging from 180 to 360 mg/day is another powerful antianginal agent in the calcium antagonist group producing excellent therapeutic benefit in chronic stable angina with no adverse effects on left ventricular function.