Food and Drug Administration (FDA) in 1967. Metoprolol, sold under the brand name Lopressor, among others, is a selective β1 receptor blocker medication.[3] 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.[3] By working on the beta-1 receptor of the cardiac muscle cells, it yields both a chronotropic and inotropic effect. Urine tests are used to detect if beta blockers are present. The FDA has approved beta blockers for the treatment of cardiac arrhythmias, hypertension, migraines, and others. Blood or plasma concentrations may be measured to confirm a diagnosis of overdose or poisoning in hospitalized patients or to assist in a medicolegal death investigation. A disadvantage to using GC-MS-SIM is that prior knowledge of the molecular structure of the target drugs/metabolites is required. However, in modern times it is increasingly difficult to detect the presence of beta blockers used for sports doping purposes. 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 and/or lips, numbness/tingling/swelling of the hands or feet, sexual dysfunction, erectile dysfunction, hair loss, mental/mood changes, depression, furosemid wirkung breathing difficulty, cough, dyslipidemia and increased thirst. Excessive doses of metoprolol can cause severe hypotension, bradycardia, metabolic acidosis, seizures, and cardiorespiratory arrest. Prescribers may choose to prescribe beta blockers for other treatments if there is just cause even though it is not approved by the FDA. Metoprolol contains a stereocenter and consists of two enantiomers. Adverse effects, especially with higher doses, include dizziness, drowsiness, fatigue, diarrhea, unusual dreams, trouble sleeping, depression, and vision problems. Metoprolol was discovered in 1969 by Bengt Ablad and Enar Carlsson.[11] Within the UK it is classified as a prescription-only drug in the beta blocker class and is regulated by the Medicines and Healthcare products Regulatory Agency (MHRA). It alleged such action by the pharmaceutical companies AstraZeneca AB, AstraZeneca LP, AstraZeneca Pharmaceuticals LP, and Aktiebolaget Hassle violated antitrust and consumer protection law. The use of beta blockers such as metoprolol was approved in the U.S. The MHRA is a government body set up in 2003 and is responsible for regulating medicines, medical devices, and equipment used in healthcare. The active substance metoprolol is employed either as metoprolol succinate or as metoprolol tartrate (where 100 mg metoprolol tartrate corresponds to 95 mg metoprolol succinate). In the 2000s a lawsuit was brought against the manufacturers of Toprol XL (a time-release formula version of metoprolol) and its generic equivalent (metoprolol-succinate) claiming that to increase profits, lower cost generic versions of Toprol XL were intentionally kept off the market.

Tamoxifen alternatives

Some bans, as in all forms of billiards, darts, and golf, apply during competition only. Because beta blockers can be used to reduce heart rate and minimize tremors, which can enhance performance in sports such as archery,[41][42] Metoprolol is banned by the world anti-doping agency in some sports. Drug manufacturers, however, are unable to advertise beta blockers for other purposes that have not been approved by the FDA. Uncharged drugs and/or metabolites of beta blockers can be analysed by gas chromatography-mass spectrometry in selected ion monitoring (GC-MS-SIM).