title: Mercaptopurine rescue after azathioprine-induced liver injury in inflammatory bowel disease.
abstract: BACKGROUND
  Azathioprine (AZA) liver toxicity arises in approximately 3% of inflammatory bowel disease patients and may result in treatment discontinuation.
  
  
  OBJECTIVE
  To describe the tolerance to mercaptopurine (MP) in patients with previous AZA-related liver injury.
  
  
  METHODS
  Retrospective description of 31 patients (14 Crohn's, 17 ulcerative colitis), in which AZA therapy was interrupted because of liver injury, with MP started as alternative therapy.
  
  
  RESULTS
  Mean AZA dose was 2.2 +/- 0.4 mg x kg/day. Median (interquartile range) of AZA exposure when liver injury was detected was 2 months (1-5.2). The type of AZA-related injury was cytolitic in 32%, cholestatic in 39% and mixed in 29%. After a median of 2.5 months (0.7-5.2), the therapy was switched to MP at a mean dose of 1.3 +/- 0.2 mg x kg/day. Median of follow-up of MP therapy was 32 months (8-54). In 87.1% of patients (95%CI: 70-96%), MP was tolerated without further liver injury; of these, 77.4% tolerated full MP doses and 9.7% tolerated lower doses. In a further cohort of 12.9% of patients, (95%CI: 3-29%), liver injury reappeared (two cholestasis, two mixed), 1-3 months after the onset of MP exposure.
  
  
  CONCLUSIONS
  The administration of MP is a good alternative in patients with AZA-related liver injury, before thiopurines are definitely discarded.
authors.affiliation: Department of Gastroenterology, Hospital Universitario de Fuenlabrada, Madrid, Spain. fbermejos@medynet.com
authors.forename: F
authors.initials: F
authors.lastname: Bermejo
authors.forename: A
authors.initials: A
authors.lastname: López-Sanromán
authors.forename: A
authors.initials: A
authors.lastname: Algaba
authors.forename: M
authors.initials: M
authors.lastname: Van-Domselaar
authors.forename: J P
authors.initials: JP
authors.lastname: Gisbert
authors.forename: S
authors.initials: S
authors.lastname: García-Garzón
authors.forename: E
authors.initials: E
authors.lastname: Garrido
authors.forename: B
authors.initials: B
authors.lastname: Piqueras
authors.forename: G
authors.initials: G
authors.lastname: De La Poza
authors.forename: I
authors.initials: I
authors.lastname: Guerra
mesh_terms: D000293:Adolescent; D000328:Adult; D001379:Azathioprine / Q000009:adverse effects*; D056486:Chemical and Drug Induced Liver Injury / Q000188:drug therapy*; D003093:Colitis, Ulcerative / Q000150:complications / Q000188:drug therapy*; D003424:Crohn Disease / Q000150:complications / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008297:Male; D015122:Mercaptopurine / Q000627:therapeutic use*; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D015122:Mercaptopurine; D001379:Azathioprine