Efficacy and safety of azathioprine and 6-mercaptopurine in Japanese pediatric patients with ulcerative colitis: a survey of the Japanese Society for Pediatric Inflammatory Bowel Disease

Abstract

Background and aims: Azathioprine (AZA) and 6-mercaptopurine (6-MP) have recently been used in Japanese pediatric patients with ulcerative colitis. The aims of this study were to evaluate both the therapeutic efficacy and safety of AZA/6-MP in this group of patients.

Methods: Fourteen members of the Japanese Society for Pediatric Inflammatory Bowel Disease reported 35 retrospective cases that received AZA/6-MP and were evaluated for adverse drug effects. In those who tolerated AZA/6-MP, disease activity and corticosteroid doses before and during the first 6 months of therapy were assessed.

Results: AZA or 6-MP was safely used in 21 of 35 patients (60%) without adverse drug effects. The disease activity began to decrease from the first month of therapy and the maximum effect was achieved after 3 months. The mean daily prednisolone dose was decreased from 26.9 to 11.6 mg and dose reduction was achieved in 58% of patients after 6 months of therapy. Fourteen of the 35 patients (40%) experienced adverse drug effects, including leukopenia (n = 11), aplastic anemia (n = 1), pancreatitis (n = 1) and liver dysfunction (n = 1).

Conclusions: The majority of Japanese children with ulcerative colitis tolerated AZA/6-MP and experienced favorable effects. However, 40% experienced adverse drug effects, mainly myelosuppression.