Exercise capacity with transdermal nitroglycerin in patients with stable angina pectoris

Transdermally delivered nitroglycerin (TTS-NTG) through a rate-controlling membrane yields stable blood levels for 24 h. We studied the effect of TTS-NTG (25 mg per 10 cm2) on exercise induced angina in 10 patients with stable angina pectoris, all in NYHA class III, who were not under treatment with other cardiac drugs. In a pre-study exercise test, all patients had angina pectoris and more than one mm ST depression. The study was placebo controlled and double blind with a randomized cross-over. Exercise tests were carried out on a treadmill according to the Bruce-protocol, 12 to 16 h after administration of TTS-NTG or of an identical placebo. After a 48 h wash-out period, the procedure was repeated after application of a plaster with the alternative content. A significant improvement was seen on TTS nitroglycerin compared with placebo in the total duration of exercise (7.2 +/- 3.6 min (mean +/- SD) vs 6.2 +/- 3.8 min; P less than 0.002). In 7 patients, the time to onset of angina was extended by TTS nitroglycerin. Maximal ST depression (lead V4 and V6) was significantly lower on TTS nitroglycerin (1.85 +/- 1 mm) compared with placebo (2.2 +/- 1 mm; P less than 0.05). It is concluded that 12 to 16 h after administration, transdermally delivered nitroglycerin improves exercise capacity and reduces maximal ST depression in patients with stable angina.