Influence of Transdermal Nitrates on Exercise Capacity in Patients with Stable Angina

Twenty patients completed a double-blind cross-over study to determine the influence of a transdermal preparation of Nitroglycerin on exercise perform ance in stable angina. Angiographically proven two or three vessel coronary disease was present in all. After a base-line exercise test the active device was titrated to efficacy or side effects and the number of patches thereafter re mained constant (2-6 patches per day; mean 3.5). Patients were randomly allo cated to active treatment or placebo, and further exercise tests were performed at 2 hours and 26 hours after application of the device. Patients were then crossed over after one days rest to the opposite treatment group, and exercise studies repeated. Two hours after application of transdermal nitroglycerin total exercise duration increased (mean 14.0 minutes) compared to placebo (12.5 minutes) and control (12.0 minutes) (p < 0.05). This effect was maintained at 26 hours. Exercise time to anginal threshold (angina + 1.5 mm ST segment depression) was increased at 2 hours and 26 hours with active drug by 11 % compared to placebo and by 22% in comparison to control. Double product of heart rate and blood pressure was not significantly different in treated and placebo groups. Oral nitroglycerin consumption assessed during the titration phase was reduced by 71%. It is concluded that transdermal nitroglycerin sig nificantly increases exercise capacity in patients with stable angina, with an effect that is maintained over a 24-hour period using a single dose application.