Intermittent nitrate therapy for prior myocardial infarction does not induce rebound angina nor reduce cardiac events

Objective Long-term nitrate therapy for ischemic heart disease may cause dr ug tolerance which diminishes its beneficial effects; consequently, intermi ttent administration of nitrates is recommended. With this regimen, however , the potential occurrence of rebound angina during the nitrate-free interv als is a source of concern. Subjects and Methods We carried out a retrospective study of 606 patients t o determine whether rebound angina occurred when conventional continuous ni trate administration was replaced by intermittent administration as part of a long-term therapy protocol for prior myocardial infarction, The subjects were receiving treatment for myocardial infarction and included 293 patien ts treated with nitrates (Nitrate group) and 313 patients who were not (No- nitrate group). The former included 186 patients who received intermittent nitrate administration (Intermittent group) and 107 patients who received c ontinuous administration (Continuous group). The mean period of observation was 4.3+/-1.6 months. Results There were no cases of rebound angina in the Intermittent group. Ca rdiac events occurred in one case in the No-nitrate group (0.3%), in 4 case s in the Continuous group (3.7%) and in 2 cases in the Intermittent group ( 1.1%), The incidence of cardiac events was thus significantly increased in the Continuous group compared to the No-nitrate group (p<0.05; odds ratio 9 .06; 95% CI 1.41-58.28), The Intermittent group did not significantly diffe r from the No-nitrate group in the incidence of cardiac events, Conclusion It is concluded that intermittent administration of nitrates doe s not cause rebound angina and is therefore safe. A randomized controlled t rial is needed to find the long-term effect on cardiac events.