What is the treatment for anaphylaxis?

Treatment for Anaphylaxis

Intramuscular epinephrine is the first-line treatment for anaphylaxis and should be administered immediately upon recognition of symptoms. 1 This life-saving medication is the only first-line treatment for this potentially fatal allergic reaction.

Initial Emergency Management

1. Administer epinephrine immediately:

   • Adults and children ≥30 kg: 0.3-0.5 mg (0.3-0.5 mL of 1:1000 concentration)
   • Children <30 kg: 0.01 mg/kg (0.01 mL/kg of 1:1000 concentration), maximum 0.3 mg
   • Administer intramuscularly into the anterolateral thigh 1
   • May repeat every 5-15 minutes if symptoms persist

2. Position the patient appropriately:

   • Supine with legs elevated if hypotensive
   • Sitting up if respiratory distress is predominant 1

3. Activate emergency response system (call 911) 1

4. Assess and support airway, breathing, circulation:

   • Administer supplemental oxygen if needed
   • Establish IV access for fluid resuscitation 1

Secondary Interventions (only after epinephrine)

1. Fluid resuscitation for hypotension:

   • Normal saline 1-2 L IV bolus for adults 2
   • Rapid infusion may be necessary as up to 50% of intravascular fluid can transfer to extravascular space within 10 minutes during anaphylaxis 2

2. Adjunctive medications:

   • H1 antagonists (e.g., diphenhydramine 25-50 mg IV/IM)
   • H2 antagonists (e.g., ranitidine 1 mg/kg IV)
   • Corticosteroids (methylprednisolone 1-2 mg/kg IV or prednisone 0.5 mg/kg orally) 1
   • Albuterol 2.5-5 mg via nebulizer for persistent bronchospasm 1

3. For refractory cases:

   • Consider IV epinephrine (1:10,000 concentration) for profound shock unresponsive to IM epinephrine and fluid resuscitation
   • Dose: 0.05-0.1 mg administered slowly under close monitoring 1
   • Epinephrine infusion (5-15 μg/min) or dopamine (2-20 μg/kg/min) for persistent hypotension 1
   • Glucagon 1-5 mg IV over 5 minutes, followed by infusion (5-15 μg/min), particularly for patients on beta-blockers 1

Special Considerations

1. Beta-blocker complications:

   • Patients on beta-blockers may have more severe anaphylaxis
   • May be refractory to standard epinephrine doses
   • Consider glucagon administration as noted above 2

2. Monitoring for biphasic reactions:

   • Observe all patients for at least 4-6 hours after symptom resolution
   • Longer observation (8-24 hours) for severe reactions or those requiring multiple epinephrine doses 1
   • Biphasic reactions can occur up to 72 hours later in approximately 17% of patients 1, 3

Discharge Planning

1. Prescribe epinephrine auto-injector (2 devices) with proper training 1

2. Develop an emergency action plan 3

3. Refer to an allergist for identification of triggers and long-term management 1

4. Educate on allergen avoidance and proper use of epinephrine auto-injector 1

Common Pitfalls to Avoid

• Delaying epinephrine administration while giving antihistamines or corticosteroids first 4
• Underdosing epinephrine or using subcutaneous rather than intramuscular route 1
• Failing to place patients in appropriate position based on symptoms
• Discharging patients too early without adequate observation for biphasic reactions
• Not prescribing epinephrine auto-injectors at discharge or failing to provide proper training 1

Remember that there are no absolute contraindications to using epinephrine in anaphylaxis, even in elderly patients or those with cardiac disease 1. The risk of untreated anaphylaxis far outweighs the risks of appropriate epinephrine administration.