Description
Metoprolol Pharmacodynamics
In patients with myocardial infarction, intravenous metoprolol reduces chest pain and reduces the risk of atrial fibrillation and flutter. Intravenous administration of metoprolol at the first symptoms (within 24 hours after the appearance of the first symptoms) reduces the risk of myocardial infarction.
Early initiation of treatment with metoprolol leads to improvement of further prognosis of myocardial infarction treatment.
A reduction in heart rate (HR) for paroxysmal tachycardia and atrial fibrillation (flutter) is achieved.
Metoprolol is a (Zgadrenoblocker that blocks rgreceptors in doses much lower than those required to block p2-receptors. Metoprolol has little membrane-stabilizing effect and no partial agonist activity. Metoprololol reduces or inhibits the agonist effect that catecholamines produced by nervous and physical stress have on cardiac activity. This means that metoprolol has the ability to inhibit the increase in heart rate, minute volume, and myocardial contractility as well as the rise in blood pressure (BP) caused by the sudden release of catecholamines.
In patients with symptoms of obstructive lung disease, metoprolol may be administered in combination with p2-adrenomimetics if necessary. When co-administered with p2-adrenomimetics, metoprolol, in therapeutic doses, has less effect on p2-adrenomimetic-induced bronchodilation than non-selective p-adrenoblockers.
Metoprolol affects insulin production and carbohydrate metabolism to a lesser extent than non-selective p-adrenoblockers. The effect of Metoprolol on cardiovascular system (CVS) response in hypoglycemia is significantly less pronounced compared to non-selective p-adrenoblockers. Improved quality of life during treatment with Metoprolol has been observed in patients after myocardial infarction.
Indications
– supraventricular tachycardia;
– Prevention and treatment of myocardial ischemia, tachycardia, and pain in myocardial infarction or suspected myocardial infarction.
Contraindications
– II and III degree atrioventricular block, decompensated heart failure, clinically significant sinus bradycardia, sinus node weakness syndrome (except for patients with permanent pacemaker), cardiogenic shock, severe peripheral circulatory disorders, including threat of gangrene, arterial hypotension;
– metoprolol is contraindicated in patients with suspected acute myocardial infarction with HR less than 45 beats per minute, PQ interval greater than 0.24 seconds, or systolic blood pressure less than 100 mm Hg;
– known hypersensitivity to metoprolol and its components or other β-adrenoblockers;
– in the treatment of supraventricular tachycardia in patients with a systolic blood pressure of less than 110 mm Hg;
– patients receiving β-adrenoblockers are contraindicated by intravenous administration of “slow” calcium channel blockers such as verapamil;continuous or intermittent therapy with inotropic drugs acting as β-adrenomimetics;
– Under 18 years of age (efficacy and safety have not been established).
Dosage and administration
- Supraventricular tachycardia
- Start administration with 5 mg (5 ml) of Metoprolol at a rate of 1-2 mg/min. The administration may be repeated at 5-minute intervals until therapeutic effect is achieved.
- Usually the total dose is 10-15 mg (10-15 ml). The recommended maximum dose for intravenous administration is 20 mg (20 ml).
- Prevention and treatment of myocardial ischemia, tachycardia, and pain in myocardial infarction or suspected myocardial infarction
- Intravenously 5 mg (5 mL) of the drug. Can be repeated at 2-minute intervals, with a maximum dose of 15 mg (15 ml). Fifteen minutes after the last injection, administer Metoprolol for oral administration at a dose of 50 mg every 6 hours for 48 hours.
