Metoprolol, marketed under the tradename Lopressor among others, is a medication of the selective β 1 receptor blocker type. It is used to treat high blood pressure, chest pain due to poor blood flow to the heart, and a number of conditions involving an abnormally fast heart rate. It is also used to prevent further heart problems after. Seldane was used to treat allergies, hives (urticaria), and other allergic inflammatory conditions. It was withdrawn from the U.S. market in 1998. When taking metoprolol, side effects may occur, such as nausea, tiredness, shortness of breath, or slow heart rate. Other less common side effects include increased liver enzymes, weight gain, and dry eyes. Rapid Heartbeat chemotherapy side effect, causes, symptom management and when to contact your healthcare provider during cancer treatment. Flecainide is used to prevent certain types of life-threatening irregular heartbeats. Flecainide is in a class of medications called antiarrhythmics. Along with its needed effects, nebivolol (the active ingredient contained in Bystolic) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention. Find patient medical information for Lopressor Oral on WebMD including its uses, side effects and safety, interactions, pictures, warnings and user ratings. Metoprolol is used alone or in combination with other medications to treat high blood pressure. It also is used to prevent angina (chest pain) and to improve survival after a heart attack. Digoxin, sold under the brand name Lanoxin, is a prescription drug used to help treat arrhythmia (irregular heartbeat) and improve symptoms of fatigue caused by heart failure. Metoprolol is the generic form of the brand-name drug Lopressor, prescribed to treat high blood pressure and prevent angina (chest pain). Metoprolol is a type of medication called a beta blocker.