Patients with sulfonamide antimicrobial “allergy”: Are they able to tolerate sulfonamide-containing non-antimicrobial agents?

Abstract

Rationale The clinical significance of potential cross-reactivity between sulfonamide antimicrobials and other sulfonamide-containing medications is uncertain. Pharmacy records were surveyed to determine whether patients with a history of sulfonamide antimicrobial adverse reactions were prescribed other sulfonamide-containing non-antimicrobials and, if so, whether these patients experienced adverse reactions to those agents. Methods All inpatients and outpatients at Parkland Memorial Hospital with reported sulfonamide “allergy” were retrospectively cross-referenced with an extensive list of potentially cross-reactive drugs dispensed by the pharmacy over the past 8 years. Pharmacy records of adverse reactions to these non-antimicrobial sulfonamides were also surveyed. Results This search generated 247 drug dispensations in 215 patients, of whom 25 (11.6%) received medications from more than 1 class. Despite reporting a sulfonamide antimicrobial adverse reaction, each patient received 1 to 3 of the following sulfonamides: a sulfonylurea, thiazide, loop diuretic, carbonic anhydrase inhibitor, triptan, celecoxib, amprenavir, or dapsone (a sulfone). Four adverse reactions were listed (1.6% of drug dispensations), one each to glyburide, sumatriptan, furosemide, and celecoxib; none were serious or life-threatening. While a system establishing absence of cross-reactions in patients was not available, 80% of drugs were refilled at least once, suggesting they were tolerated. Conclusions In general, patients who report a sulfonamide “allergy” can safely receive a wide variety of potentially cross-reactive non-antimicrobial sulfonamides, as suggested by repeated dispensations in most, lack of serious reported adverse reactions, and low incidence of reported adverse reactions. Future prospective studies should be undertaken to confirm the trends observed here.