Atropine Dosing in Cardiac Arrest

Dosing Guidelines for Atropine in Cardiac Arrest

• The American College of Cardiology recommends an initial dose of 1 mg IV bolus of atropine for ventricular asystole during cardiac arrest, which may be repeated in 5 minutes if asystole persists, with a maximum total cumulative dose of 2.5 mg over 2.5 hours 1
• The peak action of atropine occurs within 3 minutes of IV administration, and it is indicated for ventricular asystole during cardiac arrest 1

Mechanism of Action

• Atropine is a parasympatholytic agent that reduces vagal tone, enhances sinus node discharge, and facilitates atrioventricular conduction, aiming to counter excess vagal tone contributing to asystole in cardiac arrest 1, 2

Important Considerations and Cautions

• The American Heart Association suggests that atropine doses less than 0.5 mg may result in further slowing of heart rate due to central reflex stimulation of the vagus or peripheral parasympathomimetic effects, and atropine will likely be ineffective in patients who have undergone cardiac transplantation 1, 3, 4
• Atropine should be used cautiously in the presence of acute coronary ischemia or myocardial infarction, as increased heart rate may worsen ischemia or increase infarction size 3

Pediatric Considerations

• The American Academy of Pediatrics recommends a pediatric dose of 0.02 mg/kg IV/IO of atropine, with a minimum single dose of 0.1 mg and a maximum single dose of 0.5 mg, which may be repeated once 5, 6