What is the recommended dose of amiodarone (antiarrhythmic medication) for a pediatric patient with supraventricular tachycardia (SVT)?

Amiodarone Dosing for SVT in Pediatric Patients

For hemodynamically stable SVT with a pulse in children, amiodarone is given as 5 mg/kg IV/IO over 20-60 minutes (maximum 300 mg), with the infusion rate adjusted based on clinical urgency. 1

Clinical Context and When to Use Amiodarone

Amiodarone is not a first-line agent for pediatric SVT. Before considering amiodarone, you should attempt:

• Vagal maneuvers (if patient is stable) 1
• Adenosine (0.1 mg/kg initial dose, up to 0.2 mg/kg for subsequent doses, maximum 12 mg) 1
• Synchronized cardioversion if the patient is unstable (hypotensive, heart failure, chest pain, or HR >150-200 bpm) 1

Amiodarone is reserved for SVT that is refractory to other drugs or when the patient has contraindications to first-line agents. 1

Dosing Regimen for SVT with Pulse

Loading Dose

• 5 mg/kg IV/IO over 20-60 minutes 1
• Maximum single dose: 300 mg 1
• Adjust infusion rate based on urgency—use the faster end (20 minutes) for more urgent situations 1
• Must be diluted in D5W 1

Maintenance Infusion (if needed)

• 5-15 mcg/kg/min continuous infusion 1, 2, 3
• Start at 5 mcg/kg/min and titrate upward as needed 2, 3
• Concentration should not exceed 2 mg/mL 1
• Median effective maintenance dose in pediatric studies: 10-15 mcg/kg/min 2, 3

Time to Effect

• Therapeutic effect typically occurs within 24-30 hours (range 1-103 hours) 2, 3
• The long half-life means full antiarrhythmic effect may take days despite adequate serum levels 4

Critical Safety Considerations

Mandatory Monitoring

Continuous ECG monitoring is absolutely required during administration to detect: 1

• Bradycardia (occurs in ~5% of cases) 5
• Heart block 1
• QT prolongation and risk of torsades de pointes 1
• Hypotension (occurs in ~16% of IV cases) 5, 2, 3

Contraindications

Do not use amiodarone in: 1

• Severe sinus node dysfunction
• Marked sinus bradycardia
• Second- or third-degree AV block (unless pacemaker present)
• Patients on procainamide or other QT-prolonging drugs without expert consultation

Drug Interactions to Check Before Dosing

• Beta-blockers and calcium channel blockers: Create additive AV nodal suppression—substantially increases heart block risk 5
• Digoxin: Reduce digoxin dose by 50% when starting amiodarone due to increased heart block risk 5
• Warfarin: Significant interaction requiring dose adjustment 4

Common Adverse Effects in Pediatric Patients

• Hypotension: Occurs in ~16% of IV cases, usually resolves with dose reduction 5, 2, 3
• Bradycardia: May require dose reduction 3
• Phlebitis/cellulitis: Use central venous access when possible, especially if concentration >2 mg/mL 5, 2
• Elevated liver enzymes: Monitor hepatic function 3

Special Populations

Infants and Neonates

• Same dosing applies: 5 mg/kg loading dose over 1 hour 3, 6
• Maintenance: 5-25 mcg/kg/min (median effective dose 15 mcg/kg/min) 3
• Highly effective in this age group (87-95% success rate) 3, 7, 6
• Watch for neurological side effects (rare choreatic movements reported) 3

Patients with Ventricular Dysfunction

• Amiodarone is safe in patients with depressed left ventricular function, unlike many other antiarrhythmics 2, 6
• Does not typically produce clinically significant cardiodepression 5
• This makes it particularly useful when other agents are contraindicated 2

Cardiac Arrest Context (VF/Pulseless VT)

If the patient progresses to pulseless VT or VF, the dosing changes: 1

• 5 mg/kg rapid IV/IO bolus (maximum 300 mg) 1
• May repeat up to 2 additional times for refractory VF/pulseless VT 1
• Maximum total daily dose: 15 mg/kg 1
• Give after defibrillation and epinephrine have been initiated 1

Critical Pitfalls to Avoid

1. Do not confuse with amrinone—potential fatal complications if drugs are interchanged 1
2. Do not use with procainamide simultaneously without expert consultation—both prolong QT interval 1
3. Do not use peripheral IV for prolonged infusions if concentration >2 mg/mL—high risk of phlebitis 5
4. Cardiologist consultation is strongly recommended when considering amiodarone outside cardiac arrest settings due to long half-life and potential drug interactions 1
5. Do not expect immediate effect—unlike adenosine, amiodarone may take hours to days for full effect 4, 2, 3

Evidence Quality Note

The pediatric evidence for amiodarone in SVT comes primarily from case series and observational studies showing 77-95% effectiveness 2, 3, 7, 6. The 2018 AHA guidelines focus on VF/pulseless VT, with SVT dosing recommendations coming from the 2008 Pediatrics emergency drug guidelines 1 and 2010 ILCOR consensus 1. While not based on randomized trials, the consistent efficacy across multiple pediatric studies (including infants as young as 1 day old) supports its use as a second-line agent for refractory SVT 2, 3, 7, 6.