title: Update 2014: advances to optimize 6-mercaptopurine and azathioprine to reduce toxicity and improve efficacy in the management of IBD.
abstract: BACKGROUND
  The thiopurine drugs, 6-mercaptopurine (6-MP) and azathioprine (AZA), remain as a mainstay therapy in inflammatory bowel disease (IBD). Differences in metabolism of these drugs lead to individual variation in thiopurine metabolite levels that can determine its therapeutic efficacy and development of adverse reactions. In this update, we will review thiopurine metabolic pathway along with the up-to-date approaches in administering thiopurine medications based on the current literature.
  
  
  METHODS
  A search of the PubMed database by 2 independent reviewers identifying 98 articles evaluating thiopurine metabolism and IBD management.
  
  
  RESULTS
  Monitoring thiopurine metabolites can assist physicians in optimizing 6-MP and AZA therapy in treating patients with IBD. Of the dosing strategies reviewed, we found evidence for monitoring thiopurine metabolite level, use of allopurinol with thiopurine, use of mesalamine with thiopurine, combination therapy with thiopurine and anti-tumor necrosis factor agents, and split dosing of AZA or 6-MP to optimize thiopurine therapy and minimize adverse effects in IBD.
  
  
  CONCLUSIONS
  Based on the currently available literature, various dosing strategies to improve therapeutic response and reduce adverse reactions can be considered, including use of allopurinol with thiopurine, use of mesalamine with thiopurine, combination therapy with thiopurine and anti-tumor necrosis factor agents, and split dosing of thiopurine.
authors.affiliation: *Department of Medicine, Olive View-University of California Los Angeles Medical Center, Los Angeles, California; and †F. Widjaja Foundation, Inflammatory Bowel and Immunology Research Institute, Cedars-Sinai Medical Center, Los Angeles, California.
authors.forename: Jaimin
authors.initials: J
authors.lastname: Amin
authors.forename: Brian
authors.initials: B
authors.lastname: Huang
authors.forename: Jessica
authors.initials: J
authors.lastname: Yoon
authors.forename: David Q
authors.initials: DQ
authors.lastname: Shih
mesh_terms: D001379:Azathioprine / Q000627:therapeutic use*; D019468:Disease Management; D006801:Humans; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D015212:Inflammatory Bowel Diseases / Q000188:drug therapy*; D015122:Mercaptopurine / Q000627:therapeutic use*; D011379:Prognosis; D013997:Time Factors
chemical_list: D007166:Immunosuppressive Agents; D015122:Mercaptopurine; D001379:Azathioprine