[PLacebo-controlled double blind study of the anti-ischemic efficacy of transdermal depot nitrate]

Twelve patients with stable angina pectoris were studied in a randomized double blind cross-over placebo-controlled manner utilizing exercise testing and measurement of ST-segment depression before, 2, 6 and 24 hours after application of a transdermal system delivering 5 mg or 10 mg nitroglycerin per day. All testings were performed at a constant work load and exercise time. Significant improvement of ST-segment depression was only seen at 2 hours (5 mg: -45%, 10 mg: -55%) and 6 hours (5 mg: -16%, 10 mg: -31%) but not at 24 hours. The lack of efficacy at 24 hours appears to be due to tolerance.