A patient presents with acute onset of shortness of breath, hives, facial swelling, and stridor after a meal. Which medication should a paramedic administer first?

• A. Epinephrine 1:10 IVP
• B. Epinephrine 1:1 IVP
• C. Benadryl 50 mg IVP
• D. Benadryl 25 mg IVP

Answer: (A)

In anaphylaxis, the first priority is to reverse the severe allergic reaction that’s causing airway swelling and bronchospasm. Epinephrine is the drug of choice because it quickly addresses all three main problem areas: it constricts the swollen mucosa (alpha effects), relaxes bronchial smooth muscle (beta-2 effects), and supports blood pressure and heart rate (beta-1 effects). When there’s airway compromise such as stridor after a meal, rapid epinephrine is essential to reopen the airway and improve oxygenation.

Giving a diluted epinephrine IV push (1:10,000 concentration) provides a rapid, controlled systemic effect, which is safer than a more concentrated solution and is effective in a severe reaction where IV access is already established. Antihistamines like diphenhydramine may help with hives or itching but do not quickly reverse airway edema or hypotension and therefore are not the primary therapy in this scenario. They’re adjuncts after epinephrine treatment.