Long-term efficacy of continuous and intermittent use of transdermal nitroglycerin in stable angina pectoris.

To assess efficacy of transdermal nitrate use, a randomized, placebo-controlled trial of continuous and intermittent use of nitroglycerin patches (10 mg/24 hours) was conducted in 127 patients with stable angina pectoris who discontinued exercise testing within 9 minutes because of angina. After a placebo run-in week, baseline (day 0) symptom-limited exercise testing was performed and repeated on day 1 and 14 before and after the administration of 0.5 mg of sublingual nitroglycerin. On day 0, total exercise duration was the same (within narrow limits) in all 3 groups and remained unchanged in the placebo group. On day 1, total exercise duration increased from 406 +/- 115 to 469 +/- 158 seconds (p less than 0.001) in the continuously treated group and from 396 +/- 105 to 475 +/- 171 seconds (p less than 0.001) in the intermittently treated group. In the intermittent group, exercise duration increased slightly to 483 +/- 140 seconds on day 14, and in the continuous group exercise duration decreased to 447 +/- 144 seconds. However, this decrease was not statistically significant. Similar treatment effects were seen for time to 1-mm ST depression. Sublingual nitroglycerin remained effective in all 3 groups and on all days. Eleven actively treated patients and 1 patient taking placebo discontinued the study because of headache. It is concluded that continuous use of transdermal nitroglycerin remains partially effective and intermittent therapy remains fully effective in improving long-term exercise capacity with acceptable adverse effects in patients with stable angina pectoris.