The prolonged-release (also known as extended-release or sustained-release) isosorbide mononitrate tablet is a prescription medication primarily used to prevent heart-related chest pain (angina) caused by coronary artery disease. It is a long-acting nitrate that works by relaxing and widening blood vessels, which improves blood flow and oxygen supply to the heart. 

• Key Information

• Usage: It is used for the prevention of angina attacks, not for treating an acute attack that has already started, as it works too slowly.

• Dosage: The typical starting dose for adults is 30 mg or 60 mg taken once daily in the morning. The dose may be increased by a doctor if needed, up to a maximum of 120 mg or rarely 240 mg once daily.