What is the first-line treatment for systemic anaphylaxis?

What is the first-line treatment for systemic anaphylaxis?

• A. Epinephrine
• B. Diphenhydramine
• C. Hydrocortisone
• D. Saline

Answer: (A)

Epinephrine is the best first-line treatment for systemic anaphylaxis because it rapidly counteracts the life-threatening changes across the airway, breathing, and circulation that the reaction causes. It works on multiple fronts: alpha-1–mediated vasoconstriction reduces widespread vasodilation and edema, helping maintain blood pressure; beta-1 effects support heart rate and contractility to improve perfusion; beta-2–mediated bronchodilation opens the airways and further stabilizes the reaction by damping mediator release from mast cells. This combination quickly reverses airway obstruction, bronchospasm, and shock, which is why it must be given promptly, usually as an intramuscular injection in the thigh. Typical adult dosing is 0.3 to 0.5 mg per dose, with pediatric dosing around 0.01 mg/kg up to 0.3 mg, repeated every 5–15 minutes as needed. After epinephrine, provide supportive care (oxygen, IV fluids) and seek emergency help. Antihistamines and corticosteroids may be used later as adjuncts, but they do not stop the reaction quickly on their own.

Epinephrine is the best first-line treatment for systemic anaphylaxis because it rapidly counteracts the life-threatening changes across the airway, breathing, and circulation that the reaction causes. It works on multiple fronts: alpha-1–mediated vasoconstriction reduces widespread vasodilation and edema, helping maintain blood pressure; beta-1 effects support heart rate and contractility to improve perfusion; beta-2–mediated bronchodilation opens the airways and further stabilizes the reaction by damping mediator release from mast cells. This combination quickly reverses airway obstruction, bronchospasm, and shock, which is why it must be given promptly, usually as an intramuscular injection in the thigh. Typical adult dosing is 0.3 to 0.5 mg per dose, with pediatric dosing around 0.01 mg/kg up to 0.3 mg, repeated every 5–15 minutes as needed. After epinephrine, provide supportive care (oxygen, IV fluids) and seek emergency help. Antihistamines and corticosteroids may be used later as adjuncts, but they do not stop the reaction quickly on their own.