Isosorbide immediate-release tablets are used for the management of angina (chest pain) in people who have coronary artery disease (narrowing of the blood vessels that supply blood to the heart). Isosorbide extended-release (long-acting) tablets and extended-release capsules are used for the management of chest pain in people who have coronary artery disease. Isosorbide can only be used to prevent angina; it cannot be used to treat an episode of angina once it has begun. Isosorbide is in a class of medications called vasodilators.