What is the appropriate dosing regimen for amiodarone in a pediatric patient?

Amiodarone Administration in Pediatric Patients

Cardiac Arrest with Shock-Refractory VF/Pulseless VT

For pediatric cardiac arrest with ventricular fibrillation or pulseless ventricular tachycardia that persists after defibrillation and epinephrine, give amiodarone 5 mg/kg as a rapid IV/IO bolus, which may be repeated up to 2 times for refractory rhythms. 1

Dosing Protocol for Pulseless Arrest

• Initial dose: 5 mg/kg IV/IO bolus during cardiac arrest 1
• Repeat dosing: May repeat up to 2 additional times (total of 3 doses) for refractory VF/pulseless VT 1
• Timing: Administer during CPR after the second shock and epinephrine, immediately before the third shock attempt 1
• Alternative: Either amiodarone or lidocaine may be used; the 2018 AHA guidelines reaffirm that both are acceptable options, though lidocaine showed better return of spontaneous circulation in one pediatric study without difference in survival to discharge 2

Critical Administration Points

• Do not delay defibrillation to establish vascular access for amiodarone 2
• Administer during chest compressions to minimize interruptions 1
• If defibrillation is successful but VF recurs, give another bolus of amiodarone before attempting defibrillation again 1

Supraventricular Tachycardia with Perfusing Rhythm

For hemodynamically unstable SVT with a perfusing rhythm, amiodarone should be given as 5 mg/kg IV/IO over 20-60 minutes, but expert consultation is strongly recommended before administration. 1

Dosing for SVT

• Dose: 5 mg/kg IV/IO over 20-60 minutes 1
• Precaution: Expert consultation is strongly recommended prior to administration in any patient with a perfusing rhythm 1
• Monitoring: Careful hemodynamic monitoring is essential during the slow delivery, as 71% of children experienced cardiovascular side effects in one multicenter trial 3

Important Caveats

• Do not routinely administer amiodarone and procainamide together 1
• Amiodarone is typically reserved for SVT refractory to adenosine and synchronized cardioversion 1, 3
• Most pediatric efficacy data for SVT involves postoperative junctional tachycardia, limiting generalizability 3

Wide-Complex Tachycardia with Perfusing Rhythm

For unstable ventricular tachycardia with a pulse, synchronized cardioversion is preferred over amiodarone, but if drug therapy is chosen, give 5 mg/kg IV/IO over 20-60 minutes with careful hemodynamic monitoring. 1, 3

VT Treatment Algorithm

• First-line: Synchronized electric cardioversion is the preferred therapy for VT with hypotension or poor perfusion 3
• Drug therapy: If pharmacologic treatment is selected, amiodarone 5 mg/kg over 20-60 minutes is reasonable 1, 3
• Monitoring: Continuous hemodynamic monitoring is mandatory due to dose-related cardiovascular side effects 3

Torsades de Pointes

For torsades de pointes, do NOT use amiodarone—instead, give magnesium sulfate 25-50 mg/kg (maximum 2 g) IV/IO rapidly over several minutes. 1

Critical Point

• Amiodarone is a type III antiarrhythmic that can actually cause torsades de pointes by prolonging the QT interval 1
• Magnesium is the definitive treatment regardless of the underlying cause 1

General Administration Guidelines

Route and Preparation

• Routes: IV or intraosseous (IO) 1
• Endotracheal: Not recommended for amiodarone (unlike epinephrine) 1
• Central line preferred: Use central venous access when possible, as peripheral administration causes phlebitis with concentrations >2 mg/mL 4
• Filter: Use an in-line filter during administration 4

Monitoring Requirements

• Continuous ECG monitoring for heart rate, AV conduction abnormalities, and QT prolongation is mandatory 4
• Monitor blood pressure continuously, as hypotension occurs in 16% of patients receiving IV amiodarone 4
• Watch for bradycardia (occurs in 4.9% of patients) and reduce infusion rate if heart rate decreases by 10 beats per minute 4

Contraindications and Precautions

• Absolute contraindications: Second- or third-degree heart block without a pacemaker, bradycardia without pacemaker 4
• Relative contraindication: Heart rate <60 bpm without pacemaker or immediately life-threatening situation 4
• Drug interactions: Concomitant beta-blockers, calcium channel blockers, or digoxin create additive bradycardic effects 4

Maintenance Infusion (Non-Arrest Situations)

For incessant tachycardias requiring ongoing therapy beyond initial bolus dosing:

• Loading: 5 mg/kg over 1 hour 5
• Maintenance: Start at 5 mcg/kg/min and increase stepwise up to 25 mcg/kg/min until arrhythmia control or side effects occur 5
• Median effective dose: 15 mcg/kg/min (range 5-26 mcg/kg/min) 5
• Time to control: Median 24 hours (range 1-96 hours) 5

Long-Term Oral Therapy Transition

• Oral loading: 10-15 mg/kg/day, then reduce to maintenance of approximately 5 mg/kg/day 6, 7
• Half-life consideration: Amiodarone has an extremely long half-life (average 58 days, range 15-100 days), creating significant overlap between IV and oral dosing 4
• Monitoring: Check thyroid and liver function every 6 months during maintenance therapy 4

Common Pitfalls to Avoid

• Do not use in bradycardia unless the patient has a pacemaker or the situation is immediately life-threatening with no alternatives 4
• Do not delay defibrillation to give amiodarone in cardiac arrest—shock delivery and high-quality CPR are more important for survival 2
• Do not give with procainamide routinely, as combination increases risk of adverse effects 1
• Do not use for torsades de pointes—this is a contraindication; use magnesium instead 1
• Reduce digoxin dose by 50% when starting amiodarone, as digoxin levels predictably double 4
• Monitor INR weekly for first 6 weeks if patient is on warfarin, as amiodarone significantly increases anticoagulation 4