Metoprolol (Lopressor, Toprol - XL) Considerations for Use*
US/FDA Approved Indication: Heart Rate Control for Atrial Fibrillation
|Black Box Warning*||Abrupt cessation may exacerbate angina pectoris and MI.|
Mechanism of Action
Blocks binding of catecholamines to beta-1 receptors; Beta-1 selective
Acute setting: 2.5 to 5 mg IV bolus over 2 minutes; may repeat every 5 minutes to a maximum dose of 15 mg
Non-acute setting or maintenance:
Elderly: May need lower doses
Hepatic Impairment: May need lower doses
Renal Impairment: No dosage adjustment needed
|Major Side Effects||
hypotension, heart block, bradycardia, bronchospasm , HF
|Dosage forms and Strengths||
IV: 5 mL ampules (1 mg/mL)
Abrupt cessation my precipitate angina, MI, arrhythmias, or rebound HTN; discontinue by tapering over 1-2 weeks.
Immediate-release form is metoprolol tartrate; extended-release form is metoprolol succinate. When switching from immediate release to extended-release product, use same total daily dose. The immediate and extended release products may not give same clinical response on mg:mg basis; monitor response and side effects when interchanging between metoprolol products.
Concomitant amiodarone, digoxin, disopyramide, or non-dihydropyridine calcium channel blockers may increase the risk of bradycardia.
Monitor closely for HF exacerbation and hypotension when titrating dose.
* Refer to prescribing information for more complete information.
†Dosages given in the table may differ from those recommended by the manufacturers.
- American College of Cardiology (ACC), American Heart Association (AHA), and the European Society of Cardiology (ESC). ACC/AHA/ESC 2006 Guidelines for the Management of Patients with Atrial Fibrillation. Washington, DC: American College of Cardiology.
- Heart Rhythm Society. AF360 Pocket Guide: Practical Rate and Rhythm Management of Atrial Fibrillation. 2010, Washington, DC: Heart Rhythm Society.
- Tarascon Pocket Pharmacopoeia® 2012.