A nurse is caring for a client who reports difficulty breathing during the administration of an intermittent IV bolus of nafcillin. After stopping the infusion and notifying the provider, the nurse should anticipate a prescription for which of the following medications?

The correct answer is C: Epinephrine. This medication is indicated for the treatment of anaphylaxis, a severe allergic reaction that can cause difficulty breathing. Given the client's symptoms of difficulty breathing during the IV bolus administration of nafcillin, an allergic reaction is a likely cause. Epinephrine is the first-line treatment for anaphylaxis as it works quickly to constrict blood vessels, relax smooth muscles in the airways, and improve breathing. Deferoxamine (A) is used for iron toxicity, Vitamin K (B) for coagulation disorders, and Prednisone (D) for inflammation, none of which are indicated for this client's symptoms.