Metoprolol's efficacy in the management of hypertension is similar to that of other β-blockers; however, metoprolol may be preferred over a nonselective β-blocker, like propranolol, in hypertensive patients with certain concomitant disease states. Overview: Metoprolol is a beta blocker. It is is used to treat high blood pressure, chest pain, heart failure, and lower the risk of a repeat heart attack. Common side effects include tiredness. The specific agent in on-market formulations of metoprolol is either metoprolol tartrate or metoprolol succinate, where tartrate is an immediate-release formulation and the succinate is an extended-release formulation (with 100 mg metoprolol tartrate corresponding to 95 mg metoprolol succinate). Metoprolol (Lopressor®) is a medication that lowers your blood pressure and heart rate, making it easier for your heart to pump blood to the rest of your body. Know what Metoprolol Succinate ER is used for, how to take it, and which side effects to expect when starting it. Metoprolol succinate is a once-daily, extended-release beta-blocker used to treat high blood pressure, angina, and heart failure. It lowers cardiovascular risk, improves exercise tolerance, and reduces hospitalizations. Metoprolol is used alone or together with other medicines to treat high blood pressure (hypertension). High blood pressure adds to the workload of the heart and arteries. If it continues for a long time, the heart and arteries may not function properly. Learn about metoprolol succinate (Toprol XL) usage and dosing. Read the latest news and reviews about the drug as well as potential side effects and popular alternatives. TOPROL-XL, metoprolol succinate, is a beta 1 -selective (cardioselective) adrenoceptor blocking agent, for oral administration, available as extended-release tablets. TOPROL-XL has been formulated to provide a controlled and predictable release of metoprolol for once-daily administration. Metoprolol succinate is released slowly over the day, so one dose lasts about 24 hours. Only the extended-release form is approved for heart failure and for children, and only the immediate-release form is approved for use after a heart attack.