Isosorbide mononitrate belongs to the class of nitrate drugs, clinically, the commonly used nitrate drugs and nitroglycerin and isosorbide nitrate. 1. Nitroglycerin: can reduce myocardial oxygen consumption, improve myocardial perfusion, used in angina pectoris and myocardial infarction, can rapidly expand the coronary artery, restore myocardial blood supply, can reduce the scope of myocardial infarction, reduce the incidence of heart failure and ventricular fibrillation. Clinically, it is mainly used for the treatment of angina pectoris and congestive heart failure. 2. Isosorbide nitrate: its main effect is to relax the smooth muscle of blood vessels, with fast onset of action and longer lasting effect. It can be used for long-term treatment of coronary heart disease, and can also be used for the treatment of persistent angina after myocardial infarction, and also has a certain effect on pulmonary arterial hypertension. It should be noted that the main adverse effects of nitrate drugs include headache, flushing, reflex acceleration of heart rate and hypotension. Nitrate drugs are contraindicated in people who are allergic to the components of the drug, patients with glaucoma, severe anemia, patients with hypotension, and patients with hypertrophic obstructive cardiomyopathy. It is recommended to use under the supervision of a physician.