Long-term efficacy of diltiazem in chronic stable angina associated with atherosclerosis: effect on treadmill exercise.

Short-term efficacy of diltiazem in prolonging exercise end points in patients with chronic stable atherosclerosis-associated angina has been demonstrated. The safety and efficacy of diltiazem were examined in a placebo-controlled exercise study over 4 months (eight patients) and subsequently at 12 to 16 months (six patients). Three end points were evaluated: (1) time to onset of angina or fatigue if angina were eliminated; (2) time to 1 mm S-T segment depression or termination of exercise if S-T depression were eliminated; and (3) time to termination of exercise (2+ angina or fatigue). All end points were significantly prolonged over the medium-term 4 month study and decreased again significantly with return to placebo. Maximal effect occurred at 3 months with the first end point increasing from a mean +/- standard error of the mean of 7.2 +/- 1.2 to 10.2 +/- 0.9 minutes (p less than 0.01), the second end point from 8.0 +/- 0.9 to 10.3 +/- 1.0 minutes (p less than 0.01), and the third end point from 9.6 +/- 1.3 to 11.9 +/- 0.8 minutes (p less than 0.05). At 12 to 16 months efficacy was again present. Comparisons for 3 month peak effect with 12 to 16 month long-term effect and subsequent final placebo period were, respectively: first end point, 10.5 +/- 1.3, 9.4 +/- 1.0 and 6.6 +/- 1.7 minutes; second end point, 11.0 +/- 1.3, 10.2 +/- 1.2 and 6.3 +/- 0.7 minutes; and third end point, 12.1 +/- 1.0, 11.0 +/- 1.0 and 9.2 +/- 1.5 minutes. No significant adverse effects of hematologic abnormalities were noted.