Metoprolol

Metoprolol, marketed under the tradename Lopressor among others, is a medication of the selective β1 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 myocardial infarction and to prevent headaches in those with migraines. Metoprolol, marketed under the tradename Lopressor among others, is a medication of the selective β1 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 myocardial infarction and to prevent headaches in those with migraines. Metoprolol is sold in formulations that can be taken by mouth or given intravenously. The medication is often taken twice a day. The extended-release formulation is taken once per day. Metoprolol may be combined with hydrochlorothiazide (a diuretic) 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. Stopping this drug should be done slowly to decrease the risk of further health problems. Metoprolol was first made in 1969, patented in 1970, and approved for medical use in 1982. 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 2016, it was the 6th most prescribed medication in the United States, with more than 74 million prescriptions. Metoprolol is used for a number of conditions, including hypertension, angina, acute myocardial infarction, supraventricular tachycardia, ventricular tachycardia, congestive heart failure, and prevention of migraine headaches. Due to its selectivity in blocking the beta1 receptors in the heart, metoprolol is also prescribed for off-label use in performance anxiety, social anxiety disorder, and other anxiety disorders. Metoprolol is sold in formulations that can be taken by mouth or given intravenously. The medication is often taken twice a day. The extended-release formulation is taken once per day. Metoprolol may be combined with hydrochlorothiazide (a diuretic) in a single tablet. Adverse effects, especially with higher doses, include dizziness, drowsiness, fatigue, diarrhea, unusual dreams, trouble sleeping, depression, and vision problems. β-blockers, including metoprolol, reduce salivary flow via inhibition of the direct sympathetic innervation of the salivary glands. Metoprolol may also reduce blood flow to the hands or feet, causing them to feel numb and cold; smoking may worsen this effect. Due to the high penetration across the blood-brain barrier, lipophilic beta blockers such as propranolol and metoprolol are more likely than other less lipophilic beta blockers to cause sleep disturbances such as insomnia and vivid dreams and nightmares. Serious side effects that are advised to be reported immediately include symptoms of bradycardia (resting heart rate slower than 60 beats per minute), persistent symptoms of dizziness, fainting and unusual fatigue, bluish discoloration of the fingers and toes, numbness/tingling/swelling of the hands or feet, sexual dysfunction, erectile dysfunction, hair loss, mental/mood changes, depression, breathing difficulty, cough, dyslipidemia and increased thirst. Consuming alcohol while taking metoprolol may cause mild body rashes and is not advised.