Objective Long-term nitrate therapy for ischemic heart disease may cause drug tolerance which diminishes its beneficial effects ; consequently, intermittent administration of nitrates is recommended. With this regimen, however, the potential occurrence of rebound angina during the nitratefree intervals is a source of concern. Subjects and MethodsWecarried out a retrospective study of 606 patients to determine whether rebound angina occurred whenconventional continuousnitrate administration was replaced by intermittent administration as part of a long-term therapy protocol for prior myocardial infarction. Thesubjects were receiving treatment for myocardial infarction and included 293 patients treated with nitrates (Nitrate group) and 313 patients who were not (Nonitrate group). The former included 186 patients who received intermittent nitrate administration (Intermittent group) and 107 patients who received continuous administration (Continuous group). The mean period of observation was 4.3+1.6 months.