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'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. By following these dosing guidelines and monitoring protocols, metoprolol can effectively reduce morbidity and mortality in patients with hypertension, angina, and heart failure. Find patient medical information for Metoprolol (Lopressor, Toprol XL, others) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings Know what Metoprolol Succinate ER is used for, how to take it, and which side effects to expect when starting it. Read on to learn about the side effects of metoprolol, including common, severe, and long-term side effects, and how to manage them. 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. Metoprolol is a beta-blocker that affects the heart and circulation (blood flow through arteries and veins). Metoprolol is used to treat angina (chest pain) and hypertension (high blood pressure). Metoprolol is also used to lower your risk of death or needing to be hospitalized for heart failure. 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. Toprol XL (Metoprolol Succinate) may treat, side effects, dosage, drug interactions, warnings, patient labeling, reviews, and related medications including drug comparison and health resources.