[Use of nitrates after recent myocardial infarction: when, how, and why]

Nitrates are useful drugs in patients affected by recent myocardial infarction: they have an anti-ischemic and anti-anginal effect; moreover they are effective on left ventricular remodeling, with few side-effects. Meta-analysis studies performed on patients treated with nitrates intravenously for acute myocardial infarction in the pre-thrombolytic era showed a reduction of the necrotic area and of the global mortality. On the contrary experimental studies conducted using nitrates orally showed no significant clinical effects. Two post-thrombolytic studies, ISIS-4 and GISSI-3, enrolling large numbers of patients after an acute myocardial infarction, randomized to assume placebo or nitrates, administered orally and/or transdermally, demonstrated moderate and significant reductions in mortality only in some subgroups of patients treated with the active drug compared to placebo. Nitrates as drugs are "imperfect imitators" of endogenous nitrates and so can produce some negative effects. In this review the different modes of drug administration and the respective posologies of the various sublingual, spray, and oral formulations in standard, long-acting or transdermal preparations are considered. Three problems should be considered by clinicians using nitrates: resistance, tolerance and rebound. The strategies to counteract these phenomena, as well as the clinical indications and the favorable effects that can be obtained using nitrates in post-infarct patients are also discussed.