What is the dose of intramuscular (IM) adrenaline for anaphylaxis treatment?

Dosing of IM Adrenaline (Epinephrine) for Anaphylaxis Treatment

The recommended dose of intramuscular (IM) adrenaline for anaphylaxis treatment is 0.01 mg/kg of 1:1000 concentration (1 mg/mL), up to a maximum of 0.5 mg for adults and 0.3 mg for children, administered in the anterolateral thigh (vastus lateralis muscle). 1, 2

Adult Dosing

• Adults and children weighing ≥30 kg (66 lbs): 0.3-0.5 mg (0.3-0.5 mL) of undiluted 1:1000 adrenaline administered intramuscularly 2
• Maximum single dose: 0.5 mg per injection 1, 2
• Dose may be repeated every 5-10 minutes as necessary based on clinical response 2

Pediatric Dosing

• Children <30 kg (66 lbs): 0.01 mg/kg (0.01 mL/kg) of undiluted 1:1000 adrenaline administered intramuscularly 2
• Maximum single dose: 0.3 mg per injection 2
• For autoinjectors in children:
  • 0.15 mg dose for children weighing 10-25 kg (22-55 lbs) 1
  • 0.3 mg dose for children weighing ≥25 kg (55 lbs) 1
• Dose may be repeated every 5-10 minutes as necessary based on clinical response 2

Administration Technique

• Inject into the anterolateral aspect of the thigh (vastus lateralis muscle) 1, 2
• Can be administered through clothing if necessary in emergency situations 2
• When administering to children, hold the leg firmly in place to minimize risk of injection-related injury 2
• Do not administer repeated injections at the same site due to risk of tissue necrosis from vasoconstriction 2

Important Clinical Considerations

• Intramuscular injection in the lateral thigh leads to faster absorption compared to subcutaneous injection (peak plasma concentration at 8±2 minutes vs. 34±14 minutes) 1
• No absolute contraindications exist for using epinephrine to treat anaphylaxis, even in patients with cardiac disease, advanced age, or frailty 1
• Monitor the patient clinically for severity of allergic reaction and potential cardiac effects 2
• Delay in administering epinephrine has been associated with anaphylaxis fatalities and increased risk of biphasic reactions 1

Special Situations

• For severe, refractory anaphylaxis unresponsive to IM epinephrine, IV epinephrine infusion may be considered at 1-4 mcg/min, titrated up to a maximum of 10 mcg/min 3
• Biphasic reactions (recurrence of symptoms after initial resolution) may occur up to 72 hours later, with a mean of 11 hours 1
• Patients requiring more than one dose of epinephrine have higher risk of biphasic reactions 1

Common Pitfalls to Avoid

• Delaying epinephrine administration while giving antihistamines or corticosteroids first - epinephrine is the first-line treatment 1, 4
• Using subcutaneous instead of intramuscular route, which delays absorption 1
• Administering intravenous epinephrine outside of hospital settings or without appropriate monitoring, which increases risk of serious adverse effects 1
• Underdosing in adults or overdosing in small children due to fixed-dose autoinjectors 1
• Failure to repeat dose if symptoms persist 2, 4

Remember that epinephrine is the cornerstone of anaphylaxis management and should be administered promptly, as delays may be fatal 4. The intramuscular route in the lateral thigh is preferred for first-aid treatment of anaphylaxis 1.