What is the recommended dose of epinephrine (Epi) for adults and children in cases of anaphylaxis?

Recommended Epinephrine Dosing for Anaphylaxis in Adults and Children

For anaphylaxis, adults and children ≥30 kg should receive 0.3-0.5 mg epinephrine intramuscularly into the anterolateral thigh, while children <30 kg should receive 0.01 mg/kg (maximum 0.3 mg) via the same route. 1

Adult Dosing

• Adults and children weighing 30 kg (66 lbs) or more should receive 0.3-0.5 mg (0.3-0.5 mL of 1:1000 solution) of epinephrine 1
• The dose may be repeated every 5-10 minutes as necessary if symptoms persist 1
• Intramuscular injection into the anterolateral aspect of the thigh (vastus lateralis muscle) is the preferred route for first-aid treatment 2

Pediatric Dosing

• Children weighing less than 30 kg (66 lbs): 0.01 mg/kg (0.01 mL/kg of 1:1000 solution), up to a maximum of 0.3 mg 1
• For autoinjector use in children:
  • 0.15 mg autoinjector for children weighing 10-25 kg (22-55 lbs) 2
  • 0.3 mg autoinjector for children weighing approximately 25 kg (55 lbs) or more 2
  • A newer 0.1 mg autoinjector with a shorter needle is better suited for children weighing 7.5-15 kg 3

Route of Administration

• Intramuscular (IM) injection into the lateral thigh is strongly preferred over subcutaneous administration 2
• Studies show that IM injection in the lateral thigh leads to peak plasma epinephrine concentrations in 8±2 minutes, compared to 34±14 minutes with subcutaneous injection 2
• Intravenous administration carries risks of dilution errors and dosing errors and should be reserved for severe anaphylaxis that doesn't respond to IM epinephrine or for hospital settings 2

Repeat Dosing Considerations

• If symptoms persist, the dose may be repeated every 5-10 minutes as necessary 1
• Studies indicate that 8-28% of anaphylaxis patients may require a second dose of epinephrine when symptoms fail to resolve after the initial dose 4

Special Considerations

• For infants weighing less than 10 kg, the standard 0.15 mg autoinjector may exceed the recommended dose, though the clinical significance of this is unclear 3
• Autoinjector needle length may be too long for many patients weighing less than 15 kg and too short for obese patients weighing more than 30 kg 3
• In hospital settings, epinephrine drip may be considered for severe cases unresponsive to IM epinephrine, starting at 1-4 mcg/min, titrated up to a maximum of 10 mcg/min 5

Common Pitfalls to Avoid

• Confusion about proper dosing and route of administration is common among healthcare providers, with only 16.8% of junior doctors in one study administering epinephrine according to guidelines 6
• Delayed administration of epinephrine contributes to anaphylaxis fatalities; it is most effective when given immediately after symptom onset 7
• Subcutaneous injection should be avoided due to delayed onset of action 2, 7
• Intravenous administration should be avoided in first-aid settings due to increased risk of adverse effects 2, 7