What is the recommended dose and administration of epinephrine (Epi) in cases of anaphylaxis?

Epinephrine Dosing and Administration for Anaphylaxis

For anaphylaxis, epinephrine should be administered promptly via intramuscular injection into the anterolateral thigh at a dose of 0.01 mg/kg (maximum 0.3 mg in children, 0.3-0.5 mg in adults), which may be repeated every 5-10 minutes as needed based on clinical response. 1, 2

First-Line Treatment Protocol

Initial Dosing

• Adults and children ≥30 kg (66 lbs): 0.3-0.5 mg (0.3-0.5 mL of 1:1000 solution) IM 1, 2
• Children <30 kg (66 lbs): 0.01 mg/kg (0.01 mL/kg of 1:1000 solution), up to 0.3 mg IM 1, 2
• Injection site: Anterolateral aspect of the mid-thigh (vastus lateralis muscle) 1, 2
• Frequency: May repeat every 5-10 minutes as necessary based on clinical response 2

Autoinjector Recommendations

• 0.15 mg autoinjector: For children weighing 7.5-25 kg (16.5-55 lbs) 1
• 0.3 mg autoinjector: For individuals weighing ≥25 kg (55 lbs) 1

Intravenous Epinephrine for Severe Cases

Intravenous epinephrine should be reserved for:

• Cardiac arrest due to anaphylaxis
• Profound hypotension unresponsive to IM epinephrine and fluid resuscitation 1

IV Dosing Options

1. IV bolus for severe shock: 0.05-0.1 mg (0.5-1 mL of 1:10,000 solution) administered slowly 1
2. IV infusion preparation options:
   • Option 1: 1 mg (1 mL of 1:1000) in 250 mL saline (4 μg/mL), infused at 1-4 μg/min, up to 10 μg/min maximum 1
   • Option 2: 1 mg (1 mL of 1:1000) in 100 mL saline (10 μg/mL), infused at 5-15 μg/min, titrated to response 1

Important Clinical Considerations

Monitoring Requirements

• Continuous hemodynamic monitoring is essential when administering IV epinephrine 1
• If monitoring equipment is unavailable but IV epinephrine is deemed necessary, monitor vital signs every minute and use ECG if available 1

Common Pitfalls to Avoid

1. Delayed administration: Failure to promptly administer epinephrine is associated with increased mortality 3
2. Route confusion: Subcutaneous administration has delayed onset; IV administration increases risk of adverse effects 3
3. Dose confusion: Using cardiac arrest dosing (higher) for anaphylaxis (lower) can cause severe cardiac complications 4
4. Underutilization: Many clinicians hesitate to use epinephrine despite it being the definitive life-saving treatment 5

Additional Management

• Position patient recumbent with lower extremities elevated 1
• Administer oxygen at 6-8 L/min 1
• Establish IV access for fluid resuscitation (normal saline) 1
• Consider second-line agents only after epinephrine:
  • H1 antihistamines (diphenhydramine 25-50 mg IV/IM)
  • H2 blockers (ranitidine 50 mg IV)
  • Corticosteroids for preventing protracted or biphasic reactions 1

Special Situations

Refractory Anaphylaxis

• For bronchospasm resistant to epinephrine: Consider nebulized albuterol 2.5-5 mg 1
• For hypotension refractory to epinephrine and fluids: Consider vasopressor infusion (e.g., dopamine) 1
• For patients on beta-blockers: Consider glucagon 1-5 mg IV over 5 minutes, followed by infusion 1

Cardiac Arrest from Anaphylaxis

• Follow standard ACLS protocols with immediate administration of epinephrine 1
• Higher doses may be required (1-3 mg IV over 3 minutes, repeated as necessary) 1

Epinephrine remains the cornerstone of anaphylaxis management, and its prompt administration is crucial for preventing mortality. The intramuscular route in the anterolateral thigh provides the optimal balance of rapid absorption with minimal adverse effects.