What is the recommended treatment for anaphylaxis?

Anaphylaxis Treatment

Epinephrine is the cornerstone of anaphylaxis treatment and should be administered immediately as intramuscular injection into the anterolateral thigh at a dose of 0.01 mg/kg (1:1000 concentration, 1 mg/mL) to a maximum of 0.5 mg in adults and 0.3 mg in children. 1, 2

First-Line Treatment: Epinephrine

Dosing and Administration

• Adults and children ≥30 kg: 0.3-0.5 mg (0.3-0.5 mL of 1:1000 solution)
• Children <30 kg: 0.01 mg/kg (0.01 mL/kg of 1:1000 solution), maximum 0.3 mg
• Injection site: Anterolateral thigh (vastus lateralis muscle)
• Repeat doses: Every 5-15 minutes as needed if symptoms persist 1, 2

Route of Administration

• Intramuscular (IM) is the preferred route for initial treatment 1, 2
• Intravenous (IV) epinephrine should be reserved for:
  • Cardiac arrest due to anaphylaxis
  • Patients with profound hypotension unresponsive to IM epinephrine and fluid resuscitation
  • Dose: 0.05-0.1 mg (1:10,000 concentration) administered slowly 1

Additional Critical Interventions

Airway Management

• Position patient appropriately (supine with legs elevated if hypotensive)
• Assess airway, breathing, circulation
• Administer supplemental oxygen if needed
• Consider advanced airway management for severe cases with airway edema 1

Fluid Resuscitation

• For hypotension: Rapid IV fluid bolus with crystalloids (1-2 L in adults)
• Close hemodynamic monitoring is essential 1

Second-Line Treatments

Antihistamines

• H1 antagonists (e.g., diphenhydramine 25-50 mg IV/IM)
• H2 antagonists (e.g., ranitidine 1 mg/kg IV)
• Important: These treat only cutaneous symptoms and should NEVER delay epinephrine administration 1, 2

Bronchodilators

• For persistent bronchospasm: Albuterol 2.5-5 mg via nebulizer 1

Glucocorticoids

• Not helpful for acute management but may prevent protracted or biphasic reactions
• Consider methylprednisolone 1-2 mg/kg IV or prednisone 0.5 mg/kg orally 1

Special Situations

Refractory Anaphylaxis

• For hypotension unresponsive to epinephrine and fluids:
  • Consider epinephrine infusion (5-15 μg/min) 1
  • Consider dopamine (2-20 μg/kg/min) 1

Patients on Beta-Blockers

• Consider glucagon 1-5 mg IV over 5 minutes, followed by infusion (5-15 μg/min) 1

Cardiac Arrest Due to Anaphylaxis

• Standard CPR and ACLS protocols
• Higher doses of IV epinephrine may be needed 1

Post-Treatment Monitoring and Follow-up

• All patients should be observed for at least 4-6 hours after symptom resolution
• Longer observation (8-24 hours) for severe reactions or those requiring multiple epinephrine doses
• Risk of biphasic reactions (recurrence of symptoms after initial resolution) exists up to 72 hours later 1, 2
• Refer to allergist for identification of triggers and long-term management 2

Common Pitfalls to Avoid

1. Delaying epinephrine administration - associated with increased mortality 3, 4
2. Using incorrect route - IM is preferred over subcutaneous (faster absorption) 2, 5
3. Incorrect dosing - confusion between 1:1000 and 1:10,000 concentrations 6
4. Relying on antihistamines or steroids as first-line treatment - these do not address life-threatening aspects of anaphylaxis 1, 2
5. Discharging patients too early - risk of biphasic reactions 1

Remember that there are no absolute contraindications to epinephrine in anaphylaxis, even in elderly patients or those with cardiovascular disease. The benefits of prompt epinephrine administration far outweigh the risks in this life-threatening condition 1, 2.