The Safety and Efficacy of Azathioprine and 6-Mercaptopurine in the Treatment of Korean Patients with Crohn's Disease

ABSTRACT

BACKGROUND/AIMS: This study aimed to evaluate the adverse events and efficacy of azathioprine (AZA) and 6-mercaptopurine (6-MP) in Korean patients with Crohn's disease (CD). METHODS: We retrospectively analyzed 700 patients with CD (male female=469 231; median age at diagnosis, 22 years; agerange, 9-74 years) who were treated at the Asan Medical Center between January 1997 and January 2006. RESULTS: Of 700 patients, 372 (53.1%) were treated with AZA/6-MP. The cumulative rates of AZA/6-MP treatment at 1, 5, 10, and 20 years were 17.4%, 51.6%, 73.1%, and 94.5%, respectively. Of 372 patients treated with AZA/6-MP, 217 patients (58.3%) experienced 291 adverse events, requiring discontinuation of therapy in 41 patients (11%). Nausea occurred in 120 patients (32.3%) and led to discontinuation of therapy in 11 patients (3.0%). Leukopenia developed in 116 patients (31.2%), requiring dose adjustments in 100 patients (26.9%) and discontinuation of medications in 16 patients (4.3%). Other adverse events included infections (2.7%), abnormal liver function tests (2.7%), fever (0.8%), hair loss (0.8%), arthralgias (0.5%), pancreatitis (0.5%), headaches (0.5%), and skin rashes (0.3%). Complete corticosteroids withdrawal was achieved in 70.9% of the patients based on an intention-to-treat analysis. The remission rate of perianal fistulas was 32.6%. CONCLUSIONS: The risk of leukopenia by AZA/6-MP is higher in Korean patients with CD than in Western patients. Although the adverse events of AZA/6-MP are not uncommon in Korean patients with CD, the actual discontinuation rate of the treatment is low. Therefore, AZA/6-MP can be administered to most Korean patients with CD without serious adverse events.