title: Allergic reactions to 6-mercaptopurine during treatment of inflammatory bowel disease.
abstract: Hypersensitivity reactions to 6-mercaptopurine (6-MP) or azathioprine occur during the treatment of inflammatory bowel disease (IBD), raising significant diagnostic and therapeutic challenges. Charts of 591 patient with IBD treated with 6-MP in a single center were retrospectively reviewed. All allergic reactions were recorded along with results of rechallenge, desensitization, and subsequent course of IBD. Sixteen (2.7%) allergic reactions to 6-MP were noted, with fever being the most common (14 cases). Nine of these were rechallenged with 6-MP with recurrence of the same symptoms. Azathioprine was tried in six patients and in five the same symptoms recurred. Four patients underwent successful desensitization to either 6-MP or azathioprine; all four plus another patient who tolerated direct switch to azathioprine entered long-term remission. Among the remaining 11, 5 required surgery, 2 are well on methotrexate, and 4 have chronic symptoms while being treated with other medications. If an allergic reaction to 6-MP occurs during the treatment of IBD, direct switching to azathioprine is probably not justified. Instead, desensitization to either 6-MP or azathioprine should be attempted. Patients who can tolerate these medications after previous allergic reactions have improved outcomes compared with patients who resort to other forms of treatment.
authors.affiliation: Department of Medicine, Lenox Hill Hospital, New York University School of Medicine, NY, USA.
authors.forename: B I
authors.initials: BI
authors.lastname: Korelitz
authors.forename: J
authors.initials: J
authors.lastname: Zlatanic
authors.forename: F
authors.initials: F
authors.lastname: Goel
authors.forename: S
authors.initials: S
authors.lastname: Fuller
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001379:Azathioprine / Q000009:adverse effects / Q000276:immunology; D003888:Desensitization, Immunologic; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000150:complications / Q000453:epidemiology* / Q000628:therapy; D007166:Immunosuppressive Agents / Q000009:adverse effects* / Q000276:immunology; D015212:Inflammatory Bowel Diseases / Q000150:complications / Q000188:drug therapy*; D008297:Male; D015122:Mercaptopurine / Q000009:adverse effects* / Q000276:immunology; D008875:Middle Aged; D012189:Retrospective Studies
chemical_list: D007166:Immunosuppressive Agents; D015122:Mercaptopurine; D001379:Azathioprine