Description
Generic
Indications
In the treatment of angina pectoris and hypertension. Arrhythmias of the heart, particularly supraventricular tachyarrhythmias. As a supplement to hyperthyroidism treatment. The use of Metoprolol early in the course of an acute myocardial infarction lowers the extent of the infarct and the risk of ventricular fibrillation. The use of opiate analgesics may be reduced as a result of pain alleviation. When given to patients with acute myocardial infarction, metoprolol has been found to lower mortality.
Pharmacology
Metoprolol is a beta1-blocker that is selective. Metoprolol suppresses or lowers catecholamines’ agonistic impact on the heart (which are released during physical and mental stress). This means that Metoprolol reduces the typical increase in heart rate, cardiac output, cardiac contractility, and blood pressure caused by an acute increase in catecholamines. Non-selective beta-blockers interfere with insulin release and carbohydrate metabolism more than metoprolol. Non-selective beta-blockers interfere with the circulatory response to hypoglycemia far more than metoprolol does.
Dosage & Administration
Oral-
Hypertension: Total daily dosage Metoprolol 100-400 mg to be given as a single or twice daily dose. The starting dose is 100 mg (two Metoprolol-50 tablets) per day. This may be increased by 100 mg per day at weekly intervals. lf full control is not achieved using a single daily dose, a b.i.d. regimen should be initiated. Combination therapy with a diuretic or other anti-hypertensive agent may also be considered.
Angina: Usually Metoprolol 50 mg (one Metoprolol-50 tablet) to 100 mg (two Metoprolol-50 tablets) twice or three times daily.
Cardiac arrhythmias: Metoprolol 50 mg (one Metoprolol-50 tablet) b.i.d or t.i.d should usually control the condition. It necessary the dose can be increased up to 300 mg per day in divided doses. Following the treatment of an acute arrhythmia with Metoprolol injection, continuation therapy with Metoprolol tablets should be initiated 4-6 hours later. The initial oral dose should not exceed 50 mg t.i.d.
Hyperthyroidism: Metoprolol 50 mg (one Metoprolol-50 tablet) four times a day.The dose should be reduced as the euthyroid state is achieved.
Myocardial infarction: Orally, therapy should commence 15 minutes after the last injection with 50 mg every 6 hours for 48 hours. Patients who fail to tolerate the full intravenous dose should be given half the suggested oral dose. Maintenance – The usual maintenance dose is 200 mg daily given in divided doses. Elderly’ There are no special dosage requirements in otherwise healthy elderly patients. Signidcant hepatic dysfunction: A reduction in dosage may be necessary.
Injection-
Arrhythmias: By intravenous injection, up to 5 mg at a rate of 1-2 mg/minute, repeated after 5 minutes if necessary, total dose 10-15 mg.
In surgery: By slow intravenous injection 2-4 mg at induction or to control arrhythmias developing during anaesthesia; 2 mg doses may be repeated to a maximum of 10 mg.
Myocardial Infarction: Early intervention within 12 hours of infarction, by intravenous injection 5 mg every 2 minutes to a maximum of 15 mg, followed after 15 minutes by 50 mg by mouth every 6 hours for 48 hours; maintenance 200 mg daily in divided doses.
Impaired Renal Function: Dose adjustment is not needed in patients with impaired renal function.
Impaired Hepatic Function: Dose adjustment is not normally needed in patients suffering from liver cirrhosis because Metoprolol has low protein binding (5-10%). When there are signs of serious impairment of liver function (e.g. shunt-operated patients), a reduction in dose should be considered.
Elderly: Dose adjustment is not needed.
Interaction
Co-administration with CYP2D6-metabolized drugs, such as aspirin, can elevate the plasma level of metoprolol. Antiarrhythmics, antihistamines, H2 receptor antagonists, antidepressants, antipsychotics, and COX-2 inhibitors are only a few of the medications on the market. Rifampicin lowers the plasma concentration of Metoprolol.
Contraindications
AV block in the second or third degree, sick sinus syndrome, hypotension, decompensated heart failure, sinus bradycardia, severe peripheral arterial circulatory disorders, cardiogenic shock, severe asthma and bronchospasm, untreated phaeochromocytoma, Prinzmetal’s angina, metabolic acidosis.
Side Effects
Bradycardia, bronchospasm, hypotension, headache, fatigue, sleep and gastrointestinal disturbances, dizziness, vertigo, visual disturbances, and other symptoms are common.
Pregnancy & Lactation
Metoprolol should not be used during pregnancy or lactation unless the benefit outweighs the risk to the fetus or infant, according to the doctor.
Precautions & Warnings
If the heart rate is less than 40 beats per minute, the P-R interval is greater than 0.26 seconds, and the systolic blood pressure is less than 90 mmHg, or if dyspnoea or cold sweating worsens, the second or third dose should be avoided. Calcium antagonists of the Verapamil type should not be given intravenously to patients who are taking beta-blockers. When treating patients who have been diagnosed with suspected.
Therapeutic Class
Beta-blockers are drugs that block the beta-adrenoceptor.
Storage Conditions
Keep the temperature below 30°C and away from light and moisture. Keep out of children’s reach.
