Metoprolol

It is a selective (cardioselective) β ₁ -adrenergic blocker . There are two forms of derivatives: metoprolol tartrate (salts of tartaric acid) and metoprolol succinate (salts of succinic acid). Does not possess internal sympathomimetic activity. By action, it is close to atenolol .

When taken orally, it is rapidly absorbed. The half-life from blood plasma is 3-5 hours, but the effect on blood pressure and heart rate is observed (after ingestion once 100 mg) for 12 hours. It is excreted through the kidneys in the form of metabolites.

In CHF, the form of the drug metoprolol succinate (Betalok ^® ZOK, Egilok C) is used, which is a prolonged-release drug.

CR / XL ZOK technology (Controlled Release / extended Release, Zero-Order-Kinetics), in which the drug is spherical granules (microcapsules) containing the active substance compressed, coated with an ethyl cellulose polymer membrane. Evenly distributed after the tablet disintegrates throughout the digestive tract, the granules provide a constant rate of release of the substance throughout the day, regardless of the pH in the digestive tract and other physiological parameters;

Used for hypertension, angina pectoris, arrhythmias (supraventricular tachycardia, atrial fibrillation, ventricular extrasystole), with hyperthyroidism, for the prevention of repeated myocardial infarction.

Applied orally and intravenously.

Inside appoint a dose of 100-200 mg per day in 2-3 doses. If necessary, increase the dose, and in case of hypertension in case of insufficient effectiveness, additional other antihypertensive agents are prescribed.

Intravenously (for urgent indications) is administered starting with 5 mg (at a rate of 1-2 mg per minute); if necessary, re-administered at intervals of 5 minutes to a total dose of 10-15 mg. Maintenance therapy is carried out by prescribing the drug inside at a dose of 200 mg per day.

Metoprolol is used in a number of conditions, including hypertension, angina pectoris, acute myocardial infarction, supraventricular tachycardia, ventricular tachycardia, congestive heart failure, and migraine prophylaxis.

• Heart failure treatment
• Vasovagal syncope
• Adjunct in the treatment of hyperthyroidism
• Long QT Syndrome
• Prevention of Relapse of Atrial Fibrillation (Controlled Release / Sustained Release Form)

Due to its selectivity in blocking beta1 receptors in the heart, metoprolol is also prescribed for use as an off-label for anxiety, social anxiety, and other anxiety disorders.

Side effects, especially when taking higher doses, include dizziness, drowsiness, fatigue, diarrhea, unusual dreams, trouble sleeping, depression, and vision problems. β-blockers, including metoprolol, reduce saliva outflow by suppressing direct sympathetic innervation of the salivary glands. Metoprolol can also reduce blood flow to the arms or legs, making them feel numb and cold; smoking can exacerbate this effect. Due to the high penetration through 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, vivid dreams and nightmares.

Serious side effects that are recommended to be reported immediately include bradycardia symptoms (resting heart rate slower than 60 beats per minute), persistent symptoms of dizziness, fainting, and unusual tiredness, bluish discoloration of the fingers and toes, numbness / tingling / swelling arms or legs, sexual dysfunction, erectile dysfunction, hair loss, mental / mood changes, depression, shortness of breath, cough, dyslipidemia, and increased thirst. Drinking alcohol while taking metoprolol can cause a mild rash on the body and is not recommended.

Precautions

Metoprolol may worsen heart failure symptoms in some patients who may experience chest pain or discomfort, neck veins, fatigue, irregular breathing, irregular heartbeat, shortness of breath, swelling of the face, fingers, feet or legs, weight gain, or wheezing.

This medicine may cause changes in blood sugar or obscure signs of low blood sugar, such as an increased heart rate. It can also lead to some people becoming less alert than usual, making it dangerous for them to drive or use cars.

Great care is required when used in people with liver problems or asthma. This drug should be stopped slowly to reduce the risk of further health problems.

Pregnancy and lactation

Risk to the fetus is not excluded, according to the United States pregnancy category C rating. Metoprolol belongs to category C in Australia, which means that it can cause harmful effects on the human fetus (but not on malformations). It appears to be safe for breastfeeding.

Possible side effects, precautions and contraindications are the same as with other β-blockers. Metoprolol should not be administered intravenously if the systolic blood pressure is less than 110 mm Hg. Art. In patients with bronchospastic phenomena, the simultaneous administration of β-adrenostimulating drugs is recommended.

Betalok ^®, Betalok ^® KRC, Vazokardin, Vazokardin retard Korvitol ^® 100 Korvitol ^® 50, metoprolol, metoprolol Acre ^®, metoprolol-ratiopharm, metoprolol tartrate, Serdol, Egilok ^®, Egilok ^® Retard, Egilok C Emzok, Azoprol retard , Beloc, Betaloc, Blocksan, Lopressor, Veobloc, Opresol, Selopral, Specior, Presolol ^® , Metazok, etc.

Method of release: tablets of 25, 50 and 100 mg in a package of 30; 50; 100 and 200 pieces; 1% solution in ampoules of 5 ml in a package of 10 ampoules. Storage: List B. At a temperature not exceeding +25 ° C.

Metoprolol contains a stereo center and consists of two enantiomers. This is a racemate, that is, a mixture of 1: 1 ( R ) - and ( S ) -forms: ^[1]

Metoprolol was first synthesized in 1969

In the UK, metoprolol is classified as a prescription drug in the beta blocker class and is regulated by the Medicines and Medical Devices Regulatory Agency (MHRA). MHRA is a government agency established in 2003 that is responsible for the regulation of medicines, medical devices and equipment used in healthcare. MHRA recognizes that no product is completely risk free, but takes into account research and evidence to ensure that any associated risks are minimal.

The use of beta-blockers, such as metoprolol, was approved in the US by the U.S. Food and Drug Administration in 1967. The FDA has approved beta blockers for the treatment of cardiac arrhythmias, hypertension, migraines and others. Those who prescribe the drug may prescribe beta blockers for other treatments if there is only a reason, even if it is not approved by the FDA. Drug manufacturers, however, cannot advertise beta blockers for other purposes that have not been approved by the FDA. Since the FDA does not regulate medical practice after the drug has been approved, it is legal to prescribe beta blockers for other treatments, such as performance anxiety.

Legislation

MHRA issued permission to sell Intas Pharmaceuticals Limited (licenses) for metoprolol tartrate (50 and 100 mg tablets) for prescribing only on September 23, 2011; this was after it was established that there were no new or unexpected safety concerns and that the benefits of metoprolol tartrate were greater than the risks. Metoprolol tartrate is a universal version of Lopressor, which was licensed and approved on Nov. 6, 1997 for Novartis Pharmaceuticals. [34]

In sports

Metoprolol is a beta blocker and is banned by the world anti-doping agency in some sports. Beta-blockers can be used to reduce heart rate and minimize tremor, which can increase performance in sports such as archery. All beta blockers are prohibited during and outside the competition for archery and archery. In some sports, such as billiards, darts and golf, beta-blockers are prohibited only during competitions. In addition, any university sports association prohibits any form of beta blocker in shooting competitions.

To determine if beta blockers have been used, a person’s urine is analyzed. Uncharged drugs and / or beta-blocker metabolites can be analyzed by gas chromatography-mass spectrometry in selected ion monitoring (GC-MS-SIM). However, in our time it is becoming increasingly difficult to detect the presence of beta blockers used for sports doping purposes. The disadvantage of using GC-MS-SIM is that prior knowledge of the molecular structure of the target drugs / metabolites is required. Modern times have shown differences in structures, and therefore, new beta-blockers may go unnoticed.

Litigation

In 2012, an $ 11 million agreement was reached with Toprol XL (sustained release version of metoprolol) and its total equivalent metoprolol. The lawsuit involved pharmaceutical companies AstraZeneca AB, AstraZeneca LP, AstraZeneca Pharmaceuticals LP and Aktiebolaget Hassle. The lawsuit claims that manufacturers violated antitrust laws and consumer protection laws. Arguing that to increase profits, the cheaper, versatile versions of Toprol XL were intentionally taken out of the market. This claim was subsequently rejected by the defendants.