metoprolol tartrate: clinical use

Prescribing considerations

• Avoid abrupt withdrawal, particularly in ischaemic heart disease.
• Review asthma or obstructive airways disease, diabetes, first-degree AV block, peripheral vascular disease, Prinzmetal angina, psoriasis, thyrotoxicosis and hepatic impairment.
• Ensure heart failure is clinically controlled before treatment.
• Tell the anaesthetist before surgery; assess additive effects with anaesthetic and cardiovascular medicines.
• Intravenous treatment requires an appropriate monitored setting and stable haemodynamics.

Contraindications and cautions

• Hypersensitivity to metoprolol, another beta blocker or product excipients.
• Second- or third-degree AV block, clinically significant bradycardia, sick sinus syndrome without appropriate pacing, or higher-grade sinoatrial block.
• Cardiogenic shock, hypotension or unstable/decompensated heart failure.
• Severe peripheral arterial disease, metabolic acidosis or untreated phaeochromocytoma.
• Severe asthma or chronic obstructive pulmonary disease for the selected tablet product.
• Intravenous verapamil- or diltiazem-type calcium-channel blockade, or specified intravenous antiarrhythmics, with metoprolol except in the stated intensive-care context.

Monitoring

• Heart rate, blood pressure and symptoms of hypotension or worsening heart failure.
• ECG and haemodynamic status during intravenous treatment.
• Blood glucose and recognition of masked hypoglycaemia in diabetes.
• Respiratory symptoms in patients with airway disease.
• Fetal growth during pregnancy and neonatal beta-blockade effects when exposure occurs near birth.
• Clinical response and adverse effects when CYP2D6 inhibitors or other rate-limiting medicines are introduced.

Clinical pharmacology

Metoprolol is a competitive, relatively beta-1-selective antagonist without intrinsic sympathomimetic activity. Oral metoprolol undergoes substantial first-pass metabolism, mainly through CYP2D6, with clinically relevant variation between metabolisers; protein binding is low. Intravenous administration avoids absorption and first-pass stages.

Formulation and product differences

• The selected film-coated tablet is scored for equal division and its product information directs administration on an empty stomach.
• The injection is a clear intravenous solution for single use, must not be mixed with other medicines without compatibility evidence, and is intended for specialist monitored care.

Tablet

Route: Oral

Strengths: 25 mg, 50 mg, 100 mg

Injection

Route: Parenteral

Strengths: 1 mg/mL