Is it reasonably safe for patients with an allergy to sulfa to take sulfonylureas? Please elaborate on cross-reactivity associated with sulfa drugs.—DONNA O’HARA, ARNP-BC, Gainesville, Fla.

The sulfonamide component in the typical sulfa antibiotics is of a slightly different molecular structure than that in sulfonylureas. Although cross-reactivity is technically possible, current literature does not consider this likely, and sulfonylureas are typically well tolerated in patients with a sulfa allergy.—Sherril Sego, FNP-C, DNP (139-1)