Differences in the adverse effects of azathioprine between inflammatory bowel disease and autoimmune hepatitis in Korean patients

BACKGROUND/AIMS: Azathioprine (AZA) has been widely used in the therapy of inflammatory bowel disease (IBD) and autoimmune hepatitis (AIH). However, studies evaluating the adverse effects of AZA in these two diseases are lacking. The aim of this study was to compare the adverse effects of AZA in Korean IBD and AIH patients.

METHODS: Patients with IBD or AIH who were treated with AZA at Keimyung University Dongsan Medical Center (Daegu, Korea) between January 2002 and March 2011 were enrolled. Their medical records were reviewed retrospectively in terms of clinical characteristics and adverse effects of AZA.

RESULTS: A total of 139 IBD patients and 55 AIH patients were finally enrolled. Thirty IBD patients (21.6%) and eight AIH patients (14.5%) experienced adverse effects of AZA. In particular, the prevalence of leukopenia was significantly higher in the IBD group than in the AIH group (p=0.026). T474C mutation was observed in three of 10 patients who were assessed for thiopurine methyltransferase (TPMT) genotype.

CONCLUSIONS: IBD patients are at increased risk for the adverse effects of AZA compared with AIH patients, of which leukopenia was the most commonly observed. Therefore, IBD patients receiving AZA therapy should be carefully monitored.