What is "metoprolol"

n. A selective β1 receptor blocker used in treatment of several diseases of the cardiovascular system, especially hypertension.

n. beta blocker (trade name Lopressor) used in treating hypertension and angina and arrhythmia and acute myocardial infarction; has adverse side effects (depression and exacerbation of congestive heart failure etc.) [syn: Lopressor]

Metoprolol, marketed under the tradename Lopressor among others, is a selective β receptor blocker medication. 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 myocardial infarction and to prevent headaches in those with migraines.

It comes in formulations that can be taken by mouth or given intravenously. The medication is often taken twice a day. There is an extended release formulation that is once per day. Metoprolol may be combined with hydrochlorothiazide in a single tablet.

Common side effects include trouble sleeping, feeling tired, feeling faint, and abdominal discomfort. Large doses may cause serious toxicity. Risk in pregnancy has not been ruled out. It appears to be safe in breastfeeding. Greater care is required with use in those with liver problems or asthma. If stopped this should be done slowly to decrease the risk of further health problems.

Metoprolol was first made in 1969. It is on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system. It is available as a generic drug. In 2013, metoprolol was the 19th most prescribed medication in the United States.