What is the recommended dose of epinephrine (adrenaline) for an allergic reaction, specifically anaphylaxis?

Epinephrine Dosing for Allergic Reactions and Anaphylaxis

For anaphylaxis, the recommended epinephrine dose is 0.01 mg/kg (maximum 0.3 mg) for children weighing less than 30 kg and 0.3 to 0.5 mg for adults and children weighing 30 kg or more, administered intramuscularly into the anterolateral thigh. 1, 2

Dosing Guidelines by Age and Weight

Adults and Children ≥30 kg:

• Dose: 0.3 to 0.5 mg epinephrine
• Concentration: 1:1000 (1 mg/mL)
• Volume: 0.3 to 0.5 mL
• Route: Intramuscular injection into anterolateral thigh
• Frequency: Can be repeated every 5-10 minutes as necessary 2

Children <30 kg:

• Dose: 0.01 mg/kg (maximum 0.3 mg)
• Concentration: 1:1000 (1 mg/mL)
• Volume: 0.01 mL/kg (maximum 0.3 mL)
• Route: Intramuscular injection into anterolateral thigh
• Frequency: Can be repeated every 5-10 minutes as necessary 2

Special Weight Considerations:

• Children 7.5-25 kg: 0.15 mg autoinjector recommended
• Children <7.5 kg: 0.15 mg autoinjector still recommended despite exceeding 0.01 mg/kg dose
• Consider switching from 0.15 mg to 0.3 mg autoinjector at approximately 25 kg 1

Administration Technique

• Preferred site: Anterolateral thigh (vastus lateralis muscle) 1
• Intramuscular injection achieves more rapid and higher plasma concentration than subcutaneous or intramuscular injection in the arm 3
• When using an autoinjector, hold in place for 3 seconds after triggering 1
• For young children, hold the leg firmly to minimize risk of injection-related injury 1

Clinical Considerations

Indications for Repeat Dosing:

• 6-19% of pediatric patients require a second dose of epinephrine 1
• Administer second dose 5-15 minutes after the first if needed for:
  • Severe or rapidly progressive anaphylaxis
  • Failure to respond to initial injection
  • Delayed administration of initial dose
  • Inadequate initial dose 1

Common Side Effects:

• Transient effects may include pallor, tremor, anxiety, palpitations, headache, and nausea 1
• More significant side effects are more common with the 0.3 mg dose 1

Cautions:

• Use with caution in elderly patients and those with underlying cardiac disease, hyperthyroidism, Parkinson's disease, diabetes, and pheochromocytoma 1
• Serious adverse effects are rare with appropriate IM administration 1
• Do not inject into buttocks, digits, hands, or feet 2

Post-Treatment Care

• All patients who receive epinephrine for anaphylaxis should be transported to an emergency department for observation (typically 4-6 hours) 1
• Monitor vital signs, including blood pressure, heart rate, and oxygen saturation 1
• Continuous cardiac monitoring is recommended, particularly for high-risk patients 1

Common Pitfalls to Avoid

1. Delayed administration: Delayed use of epinephrine can lead to more serious anaphylaxis or ineffective treatment 3
2. Inappropriate route: Avoid subcutaneous injection as it results in slower absorption
3. Incorrect site: Never inject into buttocks, digits, hands, or feet 2
4. Substituting other medications: Antihistamines and corticosteroids are not substitutes for epinephrine in anaphylaxis 3
5. Underdosing: Using too low a dose may require repeat administration
6. Failure to carry autoinjectors: Patients at risk should carry two epinephrine autoinjectors 4

Remember that there are no contraindications to epinephrine use in a life-threatening situation such as anaphylaxis 3. Early administration is critical for preventing morbidity and mortality.