What is the recommended adenosine dose for a pediatric patient based on body weight?

Adenosine Dosing for Pediatric Patients

For pediatric supraventricular tachycardia (SVT), administer adenosine 0.1 mg/kg IV/IO as the initial dose (maximum 6 mg), followed by a rapid flush; if unsuccessful, give a second dose of 0.2 mg/kg (maximum 12 mg). 1

Initial Dose Strategy

The 2025 American Heart Association/American Academy of Pediatrics guidelines provide clear weight-based dosing 1:

• First dose: 0.1 mg/kg rapid IV/IO push (maximum 6 mg)
• Second dose: 0.2 mg/kg rapid IV/IO push (maximum 12 mg) if first dose fails
• Critical technique: Follow each dose immediately with a rapid saline flush

Evidence Supporting Higher Initial Dosing

While guidelines recommend starting at 0.1 mg/kg, the evidence strongly suggests this initial dose is insufficient for most children. Recent systematic review data from 2026 demonstrates that cardioversion success rates increase substantially with higher doses 2:

• <100 µg/kg (0.1 mg/kg): Only 25% conversion rate
• 100 µg/kg: 38% conversion rate
• 150-225 µg/kg: 47% conversion rate
• 250-400 µg/kg: 59% conversion rate

Multiple observational studies confirm that the median effective dose is actually 200 µg/kg (0.2 mg/kg), with only 36-38% of patients responding to the guideline-recommended 100 µg/kg initial dose 3, 4. This means approximately two-thirds of children will require escalation to higher doses.

Special Populations Requiring Higher Doses

Children with pre-excitation syndromes (Wolff-Parkinson-White) require significantly higher adenosine doses (mean 220 µg/kg vs. 177 µg/kg in those without pre-excitation, p=0.039) 4. If pre-excitation is suspected or documented, anticipate needing the higher 0.2 mg/kg dose or even escalation to 0.3 mg/kg.

Practical Dosing Algorithm

1. Confirm SVT diagnosis (narrow complex, HR >220/min in infants or >180/min in children, absent/abnormal P waves)
2. Establish IV/IO access and prepare rapid flush
3. First dose: 0.1 mg/kg (max 6 mg) rapid push + immediate flush
4. Wait 1-2 minutes for effect
5. If unsuccessful, second dose: 0.2 mg/kg (max 12 mg) rapid push + immediate flush
6. If still unsuccessful: Consider synchronized cardioversion (0.5-1 J/kg) or expert consultation before additional adenosine 1

Critical Safety Considerations

• Have resuscitation equipment immediately available - rare but serious complications include prolonged asystole, complete AV block, atrial fibrillation, and bronchospasm 5
• Contraindications: Second/third-degree AV block, sick sinus syndrome, asthma/bronchospastic disease, known hypersensitivity 6
• Monitor continuously during and for 2 minutes after administration
• Early recurrence occurs in 25% of cases - this is not a failure of adenosine but reflects the underlying arrhythmia mechanism 7

Common Pitfalls to Avoid

• Slow administration: Adenosine has a half-life <2 seconds; slow pushes allow metabolism before reaching the heart
• Inadequate flush: Without immediate vigorous flush, adenosine may not reach central circulation in effective concentration
• Giving up too early: Most children require 2-3 doses for successful conversion 3
• Using peripheral IV too far from central circulation: Inject as proximally as possible

The discrepancy between guideline recommendations (starting at 0.1 mg/kg) and real-world effectiveness data (median effective dose 0.2 mg/kg) reflects conservative initial dosing for safety, but clinicians should be prepared to rapidly escalate to the second dose in most patients 2, 3, 4.