[Prolonged action nitrates in stable angina pectoris]

A randomized double blind comparison of transdermal nitroglycerin and isosorbide dinitrate tablets was conducted in 100 men with stable angina pectoris. Subjective and objective effects were virtually identical for both regimens (number of angina attacks/nitroglycerin consumption and exercise ECG test variables). The pattern of side effects was also similar for both drugs. A considerable dissociation was observed between subjective effects and effects measured by ergometer test in the individual patient. Lack of both subjective and objective effects--i.e. nitrate tolerance--was observed in approximately one fourth of the patients, and was not prevented by a twelve-hour dosing interval on isosorbide dinitrate nor a six hour transdermal nitroglycerin-free interval. Our data lends credence to the notion that the effects of long-acting nitrates in daily life and the effects measured during stress testing may involve different mechanisms.