The frequency and the course of the adverse effects of azathioprine/6-mercaptopurine treatment in patients with inflammatory bowel disease

BACKGROUND/AIMS: This study was to evaluate the frequency and the course of the adverse effects of AZA/6-MP in Korean patients with inflammatory bowel disease (IBD). METHODS: Medical records of the patients with IBD treated with AZA/6-MP at Severance hospital from June 1996 to September 2006 were retrospectively analyzed. RESULTS: A total of 133 patients were studied. Male to female ratio was 1.3:1. The mean age was 31.7+/-10.9 year. Adverse effects included leukopenia occurred in 75 cases (56.4%), nausea/vomiting in 32 cases (24.1%), arthralgia in 6 cases (4.5%), hepatitis in 6 cases (4.5%), skin rash in 4 cases (3.0%), herpes zoster in 3 cases (2.3%), and headache in 1 case (0.8%). Most of leucopenia (58.7%) developed within 3 months after maximal tolerated dose of AZA/6-MP and nausea/vomiting frequently occurred within 3 months after start of AZA/6-MP treatment. Thirty-eight patients (28.6%) required the discontinuation of medication due to adverse effects. CONCLUSIONS: Leukopenia was the most common adverse effect of AZA/6-MP treatment. Leukopenia and nausea/vomiting developed frequently in the early period of treatment of AZA/6-MP in patients with IBD. AZA/6-MP should be used cautiously to scrutinize bone marrow suppression.