Intermittent or continuous transdermal nitroglycerin: still an issue, or is the case closed?

Area of Science:

• Cardiology
• Pharmacology

Background:

• Continuous nitroglycerin patch treatment for angina has faced controversy regarding tolerance development.
• The Transdermal Nitroglycerin Cooperative Study reported a lack of efficacy with continuous treatment, contributing to this debate.

Purpose of the Study:

• To reconcile conflicting study results on the efficacy of continuous nitroglycerin patch therapy for angina.
• To identify factors influencing nitrate tolerance and efficacy in angina patients.

Main Methods:

• Analysis of patient populations with varying first-dose responses to nitroglycerin.
• Evaluation of exercise test results at different time points relative to patch application.
• Comparison of continuous versus intermittent nitroglycerin patch therapy.

Main Results:

• Patient susceptibility to tolerance varies; those with a larger first-dose response are less prone to tolerance.
• Efficacy of continuous therapy can be maintained when assessed 2-5 hours post-patch renewal, despite attenuation at the end of the application period.
• Intermittent therapy generally shows superior improvement in exercise duration compared to continuous therapy.

Conclusions:

• Continuous nitroglycerin patch therapy may retain some efficacy, particularly for patients with frequent or nocturnal angina.
• Intermittent therapy is often preferred for exercise-induced angina with low first-dose effects.
• Optimal doses are typically 0.6-0.8 mg/hr, comparable to oral nitrates.