Metoprolol

Betablocking Agent · Beta-blocker

Indications

Angina pectoris. Disturbances of cardiac rhythm, myocardial infarction, functional heart disorders. Hypertension. Hyperthyroidism. Migraine prophylaxis.

Dosage

Adults: ORAL: Angina: 100 mg two or three times daily. Hypertension: 100 mg once daily, increasing if required to 400 mg daily in one or two divided doses. Thyrotoxicosis: 50 mg four times daily. Infarction: 200 mg daily. Arrhythmias: 50 mg two or three times daily; max 300 mg daily. Migraine prophylaxis: 100-200 mg daily in divided doses. Children: Not recommended. Adults: INJECTION: Arrhythmias: IV inj up to 5 mg at rate 1-2 mg/min, repeated after 5 min if necessary, total dose 10-15 mg. In surgery: By slow IV inj 2-4 mg at induction or to control arrhythmias developing during anaesthesia; 2 mg doses may be repeated to a max of 10 mg. Early intervention within 12 hr of infarction: By IV inj 5 mg every 2 min to a max of 15 mg followed after 15 min by 50 mg by mouth every 6 hr for 48 hr; maintenance 200 mg daily in divided doses. Children: Not recommended.

Administration

IV: Administer IV Push: inject slowly over 1 min. Compatibility: Stable in D5W, NS. Y-site administration: Drug to Drug IV Compatibility: Cimetidine, morphine. Drug to Drug IV Incompatibility: Amphotericin B cholesteryl sulphate complex. Stability: Do not store above 30°C (86°F). Protect from light.

Adverse Effects

Cardiovascular effects including bradycardia, postural hypotension. Rarely, heart failure, increased AV block, cardiac arrhythmias. Raynaud's phenomenon cold extremities, sexual dysfunction. GI, sleep and CNS disturbances. Dyspnoea rarely, bronchospasm. Skin reactions, withdraw if unexplained dry eyes or rash. Fatigue, paraesthesia, peripheral neuropathy, arthralgia, myopathy, altered blood sugar, haematology and lipid levels.

Risk Factor (Pregnancy/Lactation)

Pregnancy: Risk cannot be ruled out. Lactation: Caution advised or effect undetermined. Contraindications: 2nd or 3rd degree AV block (without pacemaker), severe bradycardia, sick sinus syndrome, uncontrolled heart failure, cardiogenic shock, severe peripheral arterial disease, hypotension, metabolic acidosis, untreated pheochromocytoma, severe asthma or COPD, patients at risk of hypoglycaemia, Prinzmetal's angina, history of bronchospasm. Precautions: 1st degree AV block. Heart failure (avoid if uncontrolled). Peripheral arterial circulatory disorders (avoid if severe), Prinzmetal's angina, Myasthaenia gravis. Ischaemic heart disease, withdraw gradually. History of bronchospasm. Diabetes, hyperthyroidism, renal or hepatic impairment, psoriasis. Elderly. Consider withdrawal before elective surgery. Anaphylaxis risk due to increased sensitivity to allergens. Always withdraw gradually…

Interactions

Ca++ antagonists. Antihypertensives including centrally acting agents (e.g. clonidine), antiarrhythmics, antipsychotics. TCADs, MAOIs, fluvoxamine, barbiturates, cardiac glycosides, sympathomimetics, cimetidine, hydralazine, rifampicin, NSAIDs, ergot derivatives, erythromycin, anaesthetics, diuretics, digoxin, xanthines, insulin/oral hypoglycaemics, antimalarials, moxisylyte, iodinated contrast media, baclofen, levothyroxine, alcohol, corticosteroids, rizatriptan, muscle relaxants, contraceptives, parasympathomimetics, fingolimod, ampicillin.

Advice to Patient

Take with or without meals. Do not take with antacids. Do not chew or crush tablets. Regular tablets should be taken with food. Extended release tablets may be taken with or without food. Do not stop medication abruptly, gradually decrease the dose then stop. Contact prescriber if there is unresolved swelling of extremities, difficulty in respiration, cough, unresolved fatigue, unusual weight gain, unresolved constipation or muscle weakness. Check blood pressure and pulse regularly before taking medication. Inform prescriber if pulse rate falls below 60 beats per minutes or is lower than usual. If you have diabetes, regularly check blood glucose level. Change position slowly.

Pharmacokinetics

Onset of action: Oral: Immediate release tab: Within 1 hr. Peak effect: Oral: 1-2 hrs. IV: 20 min. Duration: Oral: Immediate release: Variable (dose related). Extended release: Approx. 24 hrs. Absorption: Rapid and complete. Metabolism: Extensively hepatic; significant first-pass effect. Bioavailability: Oral: Immediate release: Approx. 40%-50%. Extended release: 77% relative to immediate release. Half-life elimination: Neonates: 5-10 hrs. Adults: 3-4 hrs. Excretion: Urine (95%).

Brands with this active ingredient

Compiled by Healify Pharmacy from published drug references. How we compile it →

Always consult a pharmacist or doctor.