What is the intramuscular epinephrine dose used in the moderate/severe anaphylaxis protocol?

• A. 0.5 mg IM
• B. 1.0 mg IM
• C. 0.05 mg IM
• D. 2.0 mg IM

Answer: (A)

Epinephrine is the first-line treatment for anaphylaxis because it rapidly counteracts airway swelling, bronchoconstriction, and hypotension by stimulating both alpha and beta receptors. For adults with moderate to severe symptoms, the standard intramuscular dose using 1:1000 concentration is 0.5 mg, given in the thigh. This dose is chosen because it provides a strong, quick response to reverse life-threatening signs while keeping systemic exposure at a safe, effective level. A dose of 0.05 mg would be far too small to achieve the needed hemodynamic and bronchodilatory effect in an adult, while 1.0 mg or 2.0 mg would raise the risk of severe tachycardia, hypertension, and other adverse effects without additional benefit in the acute setting. Pediatric dosing is different and weight-based, so the fixed adult dose is specific to adults in the protocol.