Anaphylaxis Management

Initial Treatment

Administer intramuscular epinephrine in the mid-outer thigh (vastus lateralis muscle) without delay, with a dose of 0.3-0.5 mg for adults and children ≥30 kg, and 0.01 mg/kg (maximum 0.3 mg) for children <30 kg, as recommended by the American Heart Association and the American Academy of Pediatrics 1, 2, 3, 4, 5
Activate emergency response system/call 911 simultaneously with epinephrine administration, as recommended by the American Heart Association 1, 3
Repeat epinephrine dose every 5-15 minutes if symptoms persist, as recommended by the American Heart Association and the American Academy of Pediatrics 1, 2, 3, 4, 5

Establish IV access with large-bore catheter and administer IV fluids (0.9% saline or lactated Ringer's) for hypotension or incomplete response to epinephrine, as recommended by the American Academy of Pediatrics and the Journal of Allergy and Clinical Immunology 2, 3, 5
Administer 100% oxygen to patients with anaphylaxis, and position patients appropriately, with legs elevated if hypotensive, and sitting up if experiencing respiratory distress, as recommended by the American College of Anaesthesia and the Journal of Allergy and Clinical Immunology 3, 5

Consider H1 antihistamine, such as Diphenhydramine 1-2 mg/kg or 25-50 mg IV/IM, and H2 antihistamine, such as Ranitidine 1 mg/kg IV (adults: 50 mg), as adjunctive medications after epinephrine administration, as recommended by the American Academy of Pediatrics and the Journal of Allergy and Clinical Immunology 2, 3, 5
Consider systemic glucocorticosteroids for potential biphasic reactions, as recommended by the Journal of Allergy and Clinical Immunology 6, 5
Consider nebulized albuterol 2.5-5 mg in 3 mL saline for persistent bronchospasm, as recommended by the Journal of Allergy and Clinical Immunology 6, 3, 5
Consider vasopressor infusion (e.g., dopamine 2-20 μg/kg/min) for hypotension refractory to volume replacement and epinephrine, as recommended by the Journal of Allergy and Clinical Immunology 6, 3, 5
Consider glucagon 1-5 mg IV for patients on beta-blockers with poor response, as recommended by the Journal of Allergy and Clinical Immunology 6, 3, 5

There are no absolute contraindications for using epinephrine to treat anaphylaxis, even in patients with cardiac disease, advanced age, or frailty 7
Delay in administering epinephrine has been associated with increased mortality and morbidity, and should never be delayed to administer antihistamines or steroids, as emphasized by the American Academy of Pediatrics 2, 5, 8

Biphasic reactions can occur up to 72 hours after initial symptoms resolve, with a mean of 11 hours 7
Observe patient for at least 4-6 hours after symptom resolution, and longer observation (or admission) for severe reactions or those requiring multiple epinephrine doses, as recommended by the American Academy of Pediatrics and the Journal of Allergy and Clinical Immunology 2, 5
Monitor for biphasic reactions, which can occur up to 72 hours later, although the exact monitoring period is not specified in the provided references, as noted by the American Academy of Pediatrics and the Journal of Otolaryngology-Head and Neck Surgery 2, 9

Prescribe epinephrine autoinjector (at least 2 doses) and provide anaphylaxis emergency action plan, as recommended by the American Academy of Pediatrics and the American College of Anaesthesia 3, 2
Educate on proper autoinjector use with demonstration, and arrange follow-up with allergist/immunologist, as recommended by the American Academy of Pediatrics and the Journal of Allergy and Clinical Immunology 3, 2, 5

Administering epinephrine via incorrect route (should be IM in vastus lateralis) is a common mistake to avoid 7
Discharging patients too early without adequate observation for biphasic reactions is also a common mistake to avoid, as warned by the Journal of Allergy and Clinical Immunology 10