Isosorbide is a pharmaceutical drug that is used to treat angina, heart failure, and pulmonary hypertension. Isosorbide is also known by its brand name, Isordil. However, there are many synonyms for isosorbide, including Isosorbide dinitrate, Isosorbide mononitrate, Isosorbide-5-mononitrate, and Isosorbide-2-mononitrate. These synonyms are different forms and salts of isosorbide, which are used to improve its efficacy. Isosorbide dinitrate is used to relieve chest pain, while Isosorbide mononitrate is used to prevent angina attacks. Isosorbide-5-mononitrate is used to treat heart failure, and Isosorbide-2-mononitrate is used to treat pulmonary hypertension.