For anaphylactic shock, what is the first-line intervention?

• A. Diphenhydramine IV for urticaria and itching
• B. Methylprednisolone IV
• C. Nebulized albuterol for bronchospasm resistant to epinephrine
• D. Epinephrine IM 0.3-0.5 mg

Answer: (D)

Prompt administration of epinephrine by intramuscular injection is the first-line treatment for anaphylaxis because it rapidly counteracts the main life-threatening processes: airway edema, vasodilation with hypotension, and bronchospasm. The typical adult dose is 0.3–0.5 mg of a 1:1000 solution given in the outer mid-thigh, and it should be repeated every 5–15 minutes as needed based on response. While antihistamines, steroids, and bronchodilators can be helpful as adjuncts, they do not reverse anaphylaxis as quickly or effectively as epinephrine. Epinephrine tackles multiple pathways at once, making it the essential first step to stabilize the patient.