The Clinical Use of Transdermal Delivery Devices with Nitroglycerin

Abstract

Eleven patients entered a double-blind, cross-over study that compared the influence of a new transdermal preparation of nitroglycerin (Nitrodisc: MDD-NG, Searle Limited) on exercise performance with the influence of placebo. Eight patients have completed the study. All patients had severe stable angina, and ten had angiographically proven, severe, three-vessel coro nary disease (including two patients with left main stem disease). Ejection fraction varied between 0.31 and 0.74. No patient received beta-blocking drugs or calcium antagonists at the time of entry into the study. All patients initially underwent a series of maximal treadmill exercise tests according to a modified Bruce Protocol. After a base-line exercise test, the active device was titrated to the point of efficacy or until side effects occurred. In stage 2 the patients were randomly allocated to an active or placebo group during the course of which further exercise tests were performed at two hours and 26 hours after the application of the device. In stage 3 the patients' regimens were crossed-over after one day's rest to the treatment they had not received in the first treatment period. Further exercise tests were performed at two hours and 26 hours after application of the preparation. Three days after the last 26-hour test, a further exercise test was run to determine the stability of the base-line. Three patients were removed from the study: two as a result of the appear ance of unstable angina requiring urgent coronary surgery; the third patient died from non-cardiac causes during the titration stage of the study. The mean duration of exercise at the pre-study exercise test was 11.9 minutes. Two hours after the application of MDD-NG, the mean duration of exercise increased to 14.4 minutes compared with 11.3 minutes with placebo ( P<.05). This effect was maintained at 26 hours with a mean duration of exercise of 14.1 minutes with MDD-NG compared with 11.8 minutes with placebo (P< .05). This repre sents a 30% increase in exercise capacity from base-line at two hours and 25% at 26 hours for the active drug. Exercise times to anginal threshhold associated with 1.5 mm of ST segment depression were increased by 38% at two hours after the application of MDD-NG when compared with control and was 44% at 26 hours after the application. These differences were statistically significant (P<.05). Changes in the double product of heart rate and systolic blood pressure at peak exercise were not significantly different between control, active drug, or placebo. Changes in the consumption of oral nitroglycerin were assessed during the titration phase on the active drug. From the fourth day onward the consumption of nitroglycerin was reduced by 63%. Side effects, including headache and blurring of vision, occurred in two patients; these responded readily to a reduction in dosage. It is concluded from these preliminary data that MDD-NG significantly increases exercise capacity in patients with stable angina and that this effect is maintained during a 24-hour period using a single-dose application.