Anaphylaxis Management Guidelines

Initial Treatment

The American College of Allergy, Asthma, and Immunology recommends administering epinephrine 0.01 mg/kg IM (maximum 0.5 mg) into the anterolateral thigh as the first-line treatment for anaphylaxis, which must never be delayed to give corticosteroids 3, 5, 4
Corticosteroids are effective in preventing biphasic reactions but provide no acute benefit in the immediate management of anaphylaxis—their anti-inflammatory effects do not appear for 6-12 hours after administration 2, 3, 4
Repeat epinephrine every 5-15 minutes as needed for persistent symptoms before escalating to other therapies 1, 2, 5

Methylprednisolone 1-2 mg/kg IV every 6 hours is the evidence-based dose for allergic reactions and anaphylaxis, with a typical dose of 40 mg IV for adults 1, 2, 3, 4
Diphenhydramine 25-50 mg IV (1-2 mg/kg) and ranitidine 50 mg IV or famotidine 20 mg IV should be administered in addition to methylprednisolone 1, 2, 5

For patients on beta-blockers, glucagon 1-5 mg IV over 5 minutes, followed by infusion at 5-15 mcg/min, may be considered if refractory to epinephrine and fluids 1, 2, 5
For pediatric patients on beta-blockers, the dose is 20-30 mcg/kg (maximum 1 mg) IV over 5 minutes 5

Continue methylprednisolone every 6 hours for 48-72 hours until stabilization 3, 4
Observe patients for at least 6 hours after symptom resolution, with longer observation (up to 24 hours) for severe reactions 1, 2, 3

Prescribe two epinephrine auto-injectors with hands-on training 3, 5
Continue oral prednisone 0.5-1 mg/kg daily (maximum 60-80 mg) for 2-3 days after discharge 3, 5
Provide H1-antihistamine and H2-antihistamine for 2-3 days 5

Never delay or withhold epinephrine to give corticosteroids—this is the most common and dangerous error in anaphylaxis management 3, 4
The 2-3 day oral steroid course does not require tapering 3, 5