Prevention of tolerance to nitroglycerin patches by overnight removal

This investigation assesses the extent of tolerance development with nitroglycerin patches and whether tolerance might be prevented by overnight patch removal. On commencing therapy, active patches significantly prolonged exercise time (3.5 hours after patch application) in comparison with placebo, with an accompanying reduction in ST-segment depression at maximal common workload. Patients then received continuous or 12-hour-daily intermittent patch therapy, in a double-blind fashion, for 7 days. Exercise testing was repeated before and after active patch application, on the eighth day of each treatment phase. During continuous therapy, beneficial effects on exercise time and ST depression were abolished. By contrast, during intermittent therapy, prolongation of exercise time and reduction in ST-segment depression still occurred, on testing 3.5 hours after active patch application. These results confirm previous studies showing a high degree of tolerance during continuous therapy with nitroglycerin patches and suggest that tolerance can be prevented by 12-hour-daily intermittent therapy.