Metoprolol is used for the management of hypertension and angina pectoris. It is effective in controlling cardiac arrhythmias, particularly supraventricular tachyarrhythmias. It is also used as an adjunct in the treatment of hyperthyroidism. Early use of Metoprolol in acute myocardial infarction can help reduce the size of the infarct and lower the risk of ventricular fibrillation. It may also provide pain relief and reduce the need for opioid analgesics. Additionally, it has been shown to decrease mortality in patients with acute myocardial infarction.

Metoprolol is a selective beta-1 adrenergic blocker. It works by reducing or inhibiting the effects of catecholamines on the heart, which are released during physical or emotional stress. As a result, it decreases heart rate, cardiac output, contractility, and blood pressure. Compared to non-selective beta-blockers, Metoprolol has less effect on insulin secretion and carbohydrate metabolism. It also has a lower impact on the cardiovascular response to hypoglycemia than non-selective beta-blockers.

Film-coated tablet

• 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. If 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 antihypertensive agents 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. 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. Significant hepatic dysfunction: A reduction in dosage may be necessary.

Extended-release tablet

• Hypertension: The usual initial dosage is 25 to 100 mg daily in a single dose, whether used alone or added to a diuretic.
• Angina Pectoris: The dosage of extended-release Metoprolol Succinate should be individualized. The usual initial dosage is 100 mg daily, in a single dose.
• Heart Failure: The recommended starting dose of sustained-release Metoprolol Succinate is 25 mg once daily for two weeks in patients with NYHA class II heart failure and 12.5 mg once daily in patients with more severe heart failure. The dosage may be increased at weekly (or longer) intervals until optimum blood pressure reduction is achieved. If treatment is to be discontinued, the dosage should be reduced gradually over a period of 1–2 weeks.

IV 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.

Catecholamine-depleting agents (e.g. reserpine and monoamine oxidase (MAO) inhibitors) may produce additive effects when used with beta-blockers. Drugs that inhibit CYP2D6, such as quinidine, fluoxetine, paroxetine, and propafenone, can increase plasma levels of Metoprolol, thereby reducing its cardioselectivity. Concomitant use of digitalis glycosides with beta-blockers may increase the risk of bradycardia. Beta-blockers may also intensify rebound hypertension following sudden withdrawal of clonidine.

Metoprolol is contraindicated in AV block, uncontrolled heart failure, severe bradycardia, sick sinus syndrome, cardiogenic shock, and severe peripheral arterial disease. It is also contraindicated in patients with known hypersensitivity to Metoprolol or other beta-blockers. Additionally, it should not be used when myocardial infarction is complicated by significant bradycardia, first-degree heart block, systolic hypotension (<100 mmHg), or severe heart failure.

Common side effects include tiredness, dizziness, depression, diarrhea, itching or rash, shortness of breath, slow heart rate, mental confusion, headache, somnolence, nightmares, insomnia, dyspnea, nausea, dry mouth, gastric pain, constipation, flatulence, digestive disturbances, heartburn, pruritus, musculoskeletal pain, blurred vision, decreased libido, tinnitus, and worsening of AV block.

Pregnancy Category C. Adequate and well-controlled studies in pregnant women are not available. Metoprolol should be used during pregnancy only if clearly needed. It is excreted in breast milk in very small amounts; therefore, caution is required in nursing mothers.

Bronchospastic diseases: Metoprolol may be used with caution in patients who do not respond to other antihypertensive treatment.

Major surgery: withdrawal of beta-blockers is controversial due to risk of impaired cardiac response. Diabetes: may mask tachycardia in hypoglycemia.

Peripheral vascular disease: may worsen symptoms. Calcium channel blockers: caution due to additive cardiac effects.

Hepatic impairment: use with caution.

Pediatric use: safety not established under 6 years; similar adverse events in 6–16 years vs adults

Geriatric use: no major difference in efficacy or adverse effects compared to younger patients.

May cause severe hypotension, bradycardia, AV block, heart failure, cardiogenic shock, cardiac arrest, bronchospasm, coma, nausea, vomiting, hypoglycemia and occasionally hyperkalemia. Symptoms appear within 20 minutes to 2 hours. Treatment includes monitoring vitals, gastric decontamination, activated charcoal, and supportive therapy. Sympathomimetics, atropine, inotropes, glucagon and beta-2 agonists may be used. Not effectively removed by dialysis.

Store in a cool and dry place, protected from light.