What is the recommended first-line treatment for anaphylaxis?

• A. Epinephrine 0.3-0.5 mg intramuscularly promptly, followed by airway support as needed
• B. Oral antihistamines
• C. Intravenous fluids only
• D. Corticosteroids alone

Answer: (A)

Epinephrine given by intramuscular injection is the best initial move because it quickly reverses the life-threatening changes of anaphylaxis. It works on multiple pathways at once: constricting blood vessels to raise blood pressure and reduce swelling, increasing heart output, and relaxing the airways while also curbing further mediator release from immune cells. This rapid, multi-pronged effect is what makes epinephrine essential as the first treatment. After giving it promptly, move on to airway support and other supportive measures as needed.

Oral antihistamines and corticosteroids don’t act fast enough to prevent airway compromise or shock, and they don’t reverse bronchospasm or hypotension in the acute phase. Relying on IV fluids alone isn’t sufficient to counteract the underlying bronchoconstriction and vascular permeability, and would be used in addition to epinephrine if needed.