If a patient in ventricular fibrillation (VF) achieves return of spontaneous circulation (ROSC) after receiving 450mg of Amiodarone (amiodarone), should they receive additional boluses of Amiodarone if they arrest again?

From the Guidelines

If a patient in ventricular fibrillation has already received 450 mg of amiodarone during the arrest and they achieve ROSC, and then arrest again, additional boluses of amiodarone can be administered, as the maximum recommended total dose of amiodarone in a 24-hour period is 2.2 grams, allowing for up to approximately 1.75 grams more if needed for recurrent VF, as per the guidelines outlined in the 2020 American Heart Association guidelines for cardiopulmonary resuscitation and emergency cardiovascular care 1. The standard bolus dose for subsequent arrests would remain at 300mg for the first dose, followed by 150mg for the second dose if VF persists, as indicated in the European Heart Journal study from 2001 1. It's essential to monitor for adverse effects of amiodarone, including hypotension, bradycardia, and QT prolongation. IV administration should be through a central line when possible or through a large peripheral vein. Amiodarone works by blocking sodium, potassium, and calcium channels and has both alpha and beta-blocking properties, which helps suppress ventricular arrhythmias. While administering additional amiodarone, it's crucial to continue high-quality CPR and defibrillation as indicated, as these remain the cornerstone of cardiac arrest management, as emphasized in the 2015 American Heart Association guidelines update for cardiopulmonary resuscitation and emergency cardiovascular care 1. The use of amiodarone for refractory VF/pVT is also supported by the 2020 guidelines, which recommend its administration as part of the drug therapy during the resuscitation effort 1. Key considerations in the management of cardiac arrest include:

• Continuous CPR and monitoring of CPR quality
• Epinephrine administration every 3 to 5 minutes
• Amiodarone or lidocaine for refractory VF/pVT
• Post-cardiac arrest care after ROSC is achieved. Overall, the administration of additional amiodarone boluses in this scenario is guided by the most recent and highest-quality evidence, prioritizing the patient's morbidity, mortality, and quality of life outcomes.

From the FDA Drug Label

For breakthrough episodes of VF or hemodynamically unstable VT, use 150 mg supplemental infusions of amiodarone For breakthrough episodes of VF or hemodynamically unstable VT, repeat the Initial Load

The patient should receive additional boluses of Amiodarone if they arrest again, as the label recommends repeat loading for breakthrough episodes of VF or hemodynamically unstable VT 2, 2.

• Key points:
  • The initial dose and subsequent doses are based on the clinical context and the patient's response to treatment.
  • The label does not specify a maximum cumulative dose for the treatment of VF.
  • Breakthrough episodes of VF or hemodynamically unstable VT should be treated with supplemental infusions of amiodarone.

From the Research

Amiodarone Administration in Ventricular Fibrillation

• The use of amiodarone in the management of out-of-hospital cardiac arrest, including ventricular fibrillation (VF), is supported by several studies 3, 4, 5, 6, 7.
• According to the study by 4, in patients with shockable out-of-hospital cardiac arrest who received 5 or more defibrillation attempts, a dose of amiodarone 300 mg was associated with a similar survival compared to a total dose of amiodarone 450 mg.
• The study by 7 compared intravenous amiodarone with intravenous lidocaine as an adjunct to defibrillation in victims of out-of-hospital cardiac arrest and found that amiodarone leads to substantially higher rates of survival to hospital admission in patients with shock-resistant out-of-hospital ventricular fibrillation.

Repeated Administration of Amiodarone

• There is limited information available on the repeated administration of amiodarone in patients who achieve return of spontaneous circulation (ROSC) and then experience another cardiac arrest.
• The study by 4 suggests that further study is needed to evaluate the need for a second administration of amiodarone in patients with shockable OHCA.
• The study by 6 found that amiodarone can be effective in the long-term treatment of ventricular tachycardia or ventricular fibrillation, but it causes significant toxicity in approximately 50% of patients, and the dose may need to be adjusted based on clinical response or the development of adverse effects.

Clinical Considerations

• The decision to administer additional boluses of amiodarone should be based on the individual patient's clinical situation and the potential risks and benefits of further treatment.
• The studies by 3, 5, and 7 support the use of amiodarone as an effective antiarrhythmic drug in the treatment of ventricular fibrillation, but do not provide specific guidance on repeated administration in patients who achieve ROSC and then experience another cardiac arrest.