A nurse is caring for a client who has a sulfonamide allergy. Which of the following medications should the nurse identify as contraindicated?

The correct answer is D: Glyburide. Sulfonamide antibiotics and sulfonylurea medications like glyburide share a similar chemical structure, increasing the risk of cross-reactivity in individuals with sulfonamide allergies. Famotidine (A) is an H2 blocker, not contraindicated in sulfonamide allergies. Aspirin (B) is not contraindicated unless the individual has a specific aspirin allergy. Metronidazole (C) is an antibiotic in a different class and not contraindicated in sulfonamide allergies. Thus, the nurse should identify glyburide as contraindicated due to the potential cross-reactivity in a client with a sulfonamide allergy.