A double-blind, placebo-controlled trial of sustained-release diltiazem in patients with angina. Sustained-Release Diltiazem Study Group.

The efficacy of a new sustained-release formulation of diltiazem was examined in a placebo-controlled, double-blind trial in patients with stable angina. Doses of 60 mg BID, 90 mg BID, 180 mg BID and 240 mg BID were compared with placebo in 208 patients at 3 hours and 12 hours after dosing. Diltiazem, in doses of 90 mg BID and 180 mg BID, was statistically superior to placebo with respect to increasing total exercise time. Treadmill exercise time at 3 hours postdose increased with placebo from 356.1 +/- 118.7 sec to 375.7 +/- 119.8 sec (NS); with 90 mg BID, 382.7 +/- 111.8 sec to 445.4 +/- 117.5 sec (P < 0.005); and with 180 mg BID, 386.8 +/- 145.9 sec to 467.2 +/- 166.2 sec (P < 0.0001). At 12 hours postdose, treadmill exercise time with placebo increased from 357.6 +/- 128.3 sec to 383.8 +/- 128.7 sec (NS); with 90 mg BID, 395.2 +/- 119.4 sec to 449.7 +/- 123.1 sec (P = 0.053); with 180 mg BID, 395.3 +/- 141.4 sec to 476.6 +/- 165.6 sec (P < 0.0001). Time to onset of angina was also increased by the 180-mg-BID dose both at 3 hours postdose (257.3 +/- 126.8 sec to 354.3 +/- 158.7 sec; P < 0.0001) and at 12 hours postdose (274.7 +/- 131.2 sec to 377.4 +/- 186.2 sec; P < 0.0001). Sustained-release diltiazem is effective and safe in treating patients with chronic stable angina.