Metoprolol (Lopressor, Toprol - XL) Considerations for Use*

US/FDA Approved Indication: Heart Rate Control for Atrial Fibrillation

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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:
Metoprolol tartrate (immediate-release) : 25 to 100 mg PO twice daily
Metoprolol succinate (extended-release): 25 to 200 mg daily

Elderly: May need lower doses

Hepatic Impairment: May need lower doses

Renal Impairment: No dosage adjustment needed

  • AV block
  • Bradycardia
  • cardiogenic shock
  • decompensated heart failure
  • sick sinus syndrome
  • pheochromocytoma
  • Major Side Effects

    hypotension, heart block, bradycardia, bronchospasm , HF

    Dosage forms and Strengths

    25 mg, 50 mg, 100 mg immediate-release tablets (tartrate)
    25 mg, 50 mg, 100 mg, 200 mg extended-release tablets (succinate)

    IV: 5 mL ampules (1 mg/mL)

    Special Notes

    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.


    1. 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.
    2. Heart Rhythm Society. AF360 Pocket Guide: Practical Rate and Rhythm Management of Atrial Fibrillation. 2010, Washington, DC: Heart Rhythm Society.
    3. Tarascon Pocket Pharmacopoeia® 2012.