What is the dose of atropine (antimuscarinic agent) for bradycardia in children?

Atropine Dosing for Bradycardia in Children

For symptomatic bradycardia in children, the recommended dose of atropine is 0.02 mg/kg IV/IO, with a minimum single dose of 0.1 mg and maximum single dose of 0.5 mg for children and 1.0 mg for adolescents, which can be repeated every 5 minutes to a maximum total dose of 1 mg for children and 2 mg for adolescents. 1

Dosing Algorithm

Initial Dosing

• For symptomatic vagally mediated bradycardia or AV block: 0.02 mg/kg IV/IO 1
• Minimum single dose: 0.1 mg 1
• Maximum single dose: 0.5 mg for a child, 1.0 mg for an adolescent 1
• May be administered via endotracheal tube if IV/IO access is unavailable:
  • Neonates: 0.01-0.03 mg/kg 1
  • Children and adolescents: 0.03-0.06 mg/kg 1

Repeat Dosing

• May repeat dose every 5 minutes as needed 1
• Maximum total dose: 1 mg for a child, 2 mg for an adolescent 1

Clinical Considerations

First-Line Interventions

• Oxygenation and ventilation are essential first maneuvers in treating symptomatic bradycardia 1
• Epinephrine is the drug of choice if oxygen and adequate ventilation are not effective in treating hypoxia-induced bradycardia 1

Special Situations

• For bradycardia associated with rapid sequence intubation (RSI): 0.01-0.02 mg/kg IV/IO (minimum dose: 0.1 mg; maximum dose: 1 mg) before administration of sedative/anesthetic and paralytic agents 1
• For anticholinesterase poisoning: 0.05 mg/kg IV (up to initial adult dose of 2-5 mg), repeated as needed for clinical effect 1
  • For severe poisoning, doses may need to be doubled every 5 minutes 1

Important Considerations

Minimum Dose Considerations

• Recent evidence suggests that the traditional minimum dose of 0.1 mg may not be necessary to prevent paradoxical bradycardia 1, 2
• The 2015 American Heart Association guidelines state that a dose of 0.02 mg/kg with no minimum dose may be considered when atropine is used as premedication for emergency intubation 1

Efficacy and Safety

• The dose-response relationship for atropine in children shows that 50% maximal response corresponds to 9 μg/kg, and 90% maximal response corresponds to 26 μg/kg 3
• Contrary to previous beliefs, small doses of atropine (<0.1 mg) have not been shown to cause paradoxical bradycardia in young infants 2

Administration Considerations

• Atropine sulfate comes in different concentrations; calculate dosage carefully 1
• For IV/IO administration, administer by slow push for cardiac arrest 1
• When administered via endotracheal tube, follow with or dilute in saline flush (1-5 mL) based on patient size 1

Potential Side Effects

• May cause tachycardia, which could worsen ischemia in patients with acute coronary syndrome 4
• Central nervous system effects may include hallucinations and fever with repeated administration 4

By following these dosing guidelines, clinicians can effectively manage bradycardia in pediatric patients while minimizing the risk of adverse effects.