What medications can be given prior to synchronized cardioversion?

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Last updated: June 12, 2025View editorial policy

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From the Guidelines

Prior to synchronized cardioversion, anticoagulation with a direct oral anticoagulant like apixaban (5 mg twice daily) or rivaroxaban (20 mg daily) for at least 3 weeks before cardioversion is recommended to reduce stroke risk, as stated in the 2014 AHA/ACC/HRS guideline 1. When considering medications to be given prior to synchronized cardioversion, the primary goal is to reduce the risk of thromboembolism and ensure patient comfort during the procedure.

  • For patients with hemodynamically stable atrial fibrillation lasting more than 48 hours, anticoagulation is crucial to prevent stroke.
  • The 2016 ESC guidelines for the management of atrial fibrillation suggest that pre-treatment with amiodarone, sotalol, ibutilide, or vernakalant can improve the efficacy of electrical cardioversion 1.
  • However, the most recent and highest quality study, the 2020 ESC guidelines for the management of patients with supraventricular tachycardia, does not provide specific recommendations for medications prior to synchronized cardioversion 1.
  • Therefore, based on the available evidence, anticoagulation with a direct oral anticoagulant like apixaban or rivaroxaban for at least 3 weeks before cardioversion is the recommended approach.
  • Additionally, sedation with medications like midazolam (1-2 mg IV), fentanyl (50-100 mcg IV), or propofol (0.5-1 mg/kg IV) may be administered to ensure patient comfort during the procedure.
  • The choice of medications depends on the patient's hemodynamic stability, duration of arrhythmia, and underlying cardiac condition, as well as the potential risks and benefits of each medication, as outlined in the 2016 ESC guidelines 1.

From the FDA Drug Label

5 mg should be given over a period of no less than 2 minutes. Wait an additional 2 or more minutes to fully evaluate the sedative effect. If concomitant CNS depressant premedications are used in these patients, they will require at least 50% less midazolam than healthy young unpremedicated patients Unpremedicated Patients: In the absence of premedication, an average adult under the age of 55 years will usually require an initial dose of 0.3 to 0. 35 mg/kg for induction, administered over 20 to 30 seconds and allowing 2 minutes for effect. Premedicated Patients: When the patient has received sedative or narcotic premedication, particularly narcotic premedication, the range of recommended doses is 0.15 to 0.35 mg/kg.

Medications that can be given prior to synchronized cardioversion include:

  • Midazolam (IV): 0.15 to 0.35 mg/kg for premedicated patients and 0.3 to 0.35 mg/kg for unpremedicated patients, administered over 20 to 30 seconds and allowing 2 minutes for effect.
  • Fentanyl: 1.5 to 2 mcg/kg intravenous, administered 5 minutes before induction.
  • Morphine: dosage individualized, up to 0.15 mg/kg intramuscular.
  • Meperidine: dosage individualized, up to 1 mg/kg intramuscular.
  • Hydroxyzine pamoate: 100 mg orally.
  • Sodium secobarbital: 200 mg orally. 2

From the Research

Medications for Synchronized Cardioversion

The following medications can be given prior to synchronized cardioversion:

  • Flecainide 3, 4, 5, 6
  • Propafenone 3, 4, 5, 6
  • Amiodarone 3, 7, 4, 5, 6
  • Sotalol 3, 4, 6
  • Dofetilide 3, 4, 6
  • Ibutilide 3, 4, 6
  • Vernakalant 3, 4, 6
  • Antazoline 3
  • Quinidine 4, 6
  • Procainamide 4, 6
  • Bepridil 6
  • Pilsicainide 6
  • Ranolazine 4
  • Magnesium 4

Key Considerations

When selecting a medication for synchronized cardioversion, consider the following factors:

  • Efficacy: The medication's ability to convert atrial fibrillation to sinus rhythm
  • Safety: The medication's potential side effects and risks
  • Onset of action: The time it takes for the medication to take effect
  • Patient comorbidities: The patient's underlying medical conditions and how they may interact with the medication
  • Physician experience: The physician's experience with the medication and cardioversion procedure

Medication Comparison

Studies have compared the efficacy and safety of different medications for synchronized cardioversion, including:

  • Amiodarone vs. class IC antiarrhythmic drugs 5
  • Flecainide vs. propafenone vs. amiodarone 4
  • Ibutilide vs. propafenone vs. amiodarone 6
  • Vernakalant vs. flecainide vs. amiodarone 4

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Pharmacologic cardioversion of recent-onset atrial fibrillation: a systematic review and network meta-analysis.

Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology, 2020

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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