Metoprolol succinate is the generic name for the brand medication Toprol XL. This medication is a beta-blocker used to treat high blood pressure, chest pain, and heart failure. It works by blocking the action of certain natural chemicals in the body, such as adrenaline, which can increase heart rate and blood pressure. Metoprolol succinate helps to lower blood pressure, improve blood flow, and reduce the workload on the heart. Therefore, the correct answer is Metoprolol succinate.