During a blood transfusion, a patient develops signs of anaphylaxis. After stopping the transfusion, what should be administered first?

• A. Epinephrine
• B. RhoGAM
• C. Benadryl
• D. Fresh frozen plasma

Answer: (A)

Epinephrine is the first-line treatment for anaphylaxis because it rapidly reverses the life-threatening symptoms that occur in this reaction. It acts on multiple fronts essential in anaphylaxis: it causes vasoconstriction to raise blood pressure and reduce edema, bronchodilation to open the airways, and stabilization of mast cells to limit further release of mediators. In the transfusion setting, once the transfusion is stopped to remove the trigger, giving epinephrine promptly addresses the airway compromise and potential shock that can develop within minutes.

In practical terms, administer epinephrine intramuscularly (0.3–0.5 mg of 1:1000 solution) as soon as anaphylaxis is suspected, and repeat every 5–15 minutes as needed while monitoring the patient. Provide airway support and initiate intravenous fluids to treat hypotension as needed. Adjuncts like diphenhydramine can be given after epinephrine, but they do not replace it. RhoGAM and fresh frozen plasma are not appropriate first-line treatments for acute anaphylaxis.