When admitting a client to the unit, the nurse asks about any allergies to medications. The patient replies "I am allergic to sulfa drugs."What follow-up question should be the priority for the nurse to ask?

A. "Why were you prescribed a sulfa drug?": Knowing the indication for the sulfa drug may provide some medical background but does not help determine the severity or nature of the allergic reaction, which is the nurse’s immediate concern for patient safety. B. "What was your reaction when you took the sulfa drug?": This is the priority question because it identifies whether the response was a true allergic reaction (such as rash, hives, anaphylaxis) or a non-allergic side effect. Understanding the specific reaction guides safe medication administration and helps avoid cross-reactive drugs. C. "Who is the provider that ordered it for you?": The prescriber’s identity is not relevant to determining the allergy type or its severity. The nurse’s immediate focus should be on assessing potential risks and ensuring accurate allergy documentation. D. "When did you have a reaction?": The timing of the reaction can be useful, but it is secondary to identifying the symptoms and severity. Knowing the nature of the reaction allows the healthcare team to evaluate risk more effectively and implement precautions.