Nitroglycerin is in a group of drugs called nitrates. Nitroglycerin dilates (widens) blood vessels, making it easier for blood to flow through them and easier for the heart to pump. Nitroglycerin is used to treat or prevent attacks of chest pain (angina). Nitroglycerin may also be used for other purposes not listed in this medication guide.
Nitroglycerin works by relaxing and widening blood vessels, therefore, allowing blood to flow more easily. The widening reduces the heart's workload and the level of oxygen required for the heart. Nitroglycerin is administered during the treatment of high blood pressure or when a patient is going through surgery.