Safety of azathioprine and 6-mercaptopurine in pediatric patients with inflammatory bowel disease

Gastroenterology. 1998 Oct;115(4):813-21. doi: 10.1016/s0016-5085(98)70251-3.


Background & aims: Azathioprine (AZA) and 6-mercaptopurine (6-MP) are used in pediatric patients with ulcerative colitis and Crohn's disease to reduce disease activity, maintain remission, prevent relapse, and lower corticosteroid dosage, but their long-term side effects remain to be studied. The aim of this study was to analyze the safety of AZA and 6-MP and steroid reduction in this age group.

Methods: The investigators' database identified 118 patients who received either drug; 23 were excluded (single visit, noncompliance, or therapy < 1 week), leaving 95 patients, with a mean (+/-SD) age of 14.2 +/- 4.4 years. Medical files were reviewed for adverse side effects: fever, pancreatitis, infections, gastrointestinal intolerance, aminotransferase level increase, leukopenia, and thrombocytopenia. Prednisone doses before and after immunomodulatory therapy were compared.

Results: AZA or 6-MP was tolerated in 51 of 95 patients (54%) without adverse reaction; 27 of 95 (28%) experienced side effects that responded to dose reduction (23 patients) or spontaneously (4 patients), most commonly increased aminotransferase level (13.7%). Cessation of therapy was needed in 17 of 95 patients (18%), including recurrent fever (4), pancreatitis (4), gastrointestinal intolerance (4), and recurrent infections (3). Mean prednisone dose decreased from 24.3 to 8.6 mg/day.

Conclusions: AZA and 6-MP were well tolerated in 82% of patients; of these, prednisone reduction occurred in 87%. However, 18% required discontinuation because of hypersensitivity or infectious side effects.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Azathioprine / adverse effects
  • Azathioprine / therapeutic use*
  • Child
  • Child, Preschool
  • Databases as Topic
  • Drug Hypersensitivity
  • Humans
  • Immunosuppressive Agents / adverse effects
  • Immunosuppressive Agents / therapeutic use*
  • Infections / etiology
  • Inflammatory Bowel Diseases / drug therapy*
  • Medical Records
  • Mercaptopurine / adverse effects
  • Mercaptopurine / therapeutic use*
  • Prednisone / administration & dosage
  • Prednisone / therapeutic use


  • Immunosuppressive Agents
  • Mercaptopurine
  • Azathioprine
  • Prednisone