Higher than recommend dosage of sublingual isosorbide dinitrate for treating angina pectoris: a case report and review of the literature

Nitrates primarily cause arterial and venous vasodilation effects, which increases coronary artery blood supply, and decreases cardiac preload and afterload by enhancing nitric oxide (NO) levels. The dosage of nitrates used for angina pectoris widely differs among individuals, and therapeutic resistance and tolerance gradually occur. Increasing doses of nitrates are needed to abolish ischemia chest pain onset in patients with angina pectoris, and to obtain satisfactory therapeutic effects. Here, we report the case of a 37-year-old male who was hospitalized six times, from September 2013 to April 2018, with recurrent angina pectoris. Although the patient was implanted with stents, he still presented with chest pain associated with physical efforts. Diagnosis with acute myocardial infarction was based on his ST-segment changes on electrocardiogram (ECG), elevated troponin-T level and coronary angiography. After the stents were implanted, his chest pain had no relief. Following three times of coronary angiography revealed that distal and small branch vessels still had stenosis, but was not required to revascularization. Due to serious headache resulted from sublingual or oral nitroglycerin; he had to take sublingual isosorbide dinitrate, from 20 mg to 150 mg each time, to obtain rapid relief from angina pectoris without doctor's consent. Followed up to April 2019, the patient has continued to take 100-150 mg sublingual isosorbide dinitrate for angina pectoris onset triggered by physical efforts, and has obtained remarkable relief within a few minutes, without blood pressure decrease and other side effects. Higher than recommend dosage of sublingual isosorbide dinitrate might establish better efficacy for angina pectoris in rarely patient.