Metoprolol tartrate Prolomet R tartrate is a beta adrenergic blocking agent beta blocker It works by reducing the amount of work the heart has to do reduces chest pain and the amount of blood the heart pumps out lowers high blood pressure It is also used to stabilize the heart rhythm in conditions in which the heart is beating too fast or in an irregular rhythm Treating high blood pressure alone or with other medicines long term treatment of chest pain and reducing the risk of death because of heart problems in patients who have had a heart attack It may also be used for other conditions as determined by your doctor