Transdermal nitroglycerin in angina pectoris

The transdermal nitroglycerin patches have been very successful nitrate formulations since their introduction in 1982. Nevertheless, considerable controversy regarding efficacy and tolerance has arisen. Nitroglycerin has multiple mechanisms of action in angina pectoris. Transdermal nitroglycerin in ointment formulation has been known to be effective in angina. The patches, when used in a dose of greater than or equal to 10 mg (24 h)-1, provide classic nitrate NTG effects in angina patients. However, the problem of nitrate tolerance is significant; in acute dosing, the transdermal patches lose their efficacy by 24 h and, with chronic dosing, appear usually to have little advantage over placebo in improvement of angina. An intermittent or interval approach to transdermal patch delivery appears to be the best method of avoiding nitrate tolerance. Current data suggest using the patches for 12 or 14 h consecutively and then removing them for 10-12 h. Such dosing strategies appear to eliminate or markedly reduce the problem of nitrate tolerance.