Agranulocytosis associated with sulfasalazine

Agranulocytosis is a rare but potentially lethal adverse effect of sulfasalazine. We report a case of sulfasalazine-associated agranulocytosis that occurred in a 79-year-old woman who had been taking the drug for approximately seven weeks. The patient had discontinued the drug on her own initiative nine days prior to admission. The patient was admitted with complaints of hoarseness, fever, odynophagia, and malaise. The total white blood cell count was 600/mm3 with a differential of 0% neutrophils, 8% bands, 67% lymphocytes, and 25% monocytes; a bone marrow aspirate and biopsy revealed maturation arrest. The patient's peripheral white blood cell count and differential progressively increased over the nine-day hospital course. Upon discharge the white blood cell count was 12,000 cells/mm3 with 66% neutrophils, 8% bands, 16% lymphocytes, and 10% monocytes. Complete blood counts should be performed periodically in patients receiving sulfasalazine, especially during the first two months of therapy. Pharmacists should counsel patients to discontinue the drug and consult their physician immediately if they develop unexplained fever, chills, sore throat, malaise, or other nonspecific illness during the initial two months of treatment.