title: Azathioprine formulation optimizes metabolite profile in inflammatory bowel disease.
abstract: BACKGROUND
  Recent studies have suggested that mercaptopurine metabolism is influenced by drug formulation (mercaptopurine vs. azathioprine) and concomitant use of 5-aminosalicylic acid medications.
  
  
  OBJECTIVE
  To determine the influence of dose, formulation and 5-aminosalicylic acid use on mercaptopurine metabolism.
  
  
  METHODS
  Metabolites from 131 inflammatory bowel disease patients were analysed. Logistic regression was used to analyse correlations between dose and metabolite levels. Multivariate analysis was used to determine the effects of drug formulation and 5-aminosalicylic acid use.
  
  
  RESULTS
  A positive correlation was detected between dose and 6-tioguanine nucleotides levels for azathioprine/Imuran formulation (P = 0.005) but not for mercaptopurine formulation. Adjusted mean 6-tioguanine nucleotides levels were similar for both formulations. Adjusted mean 6-methylmercaptopurine levels were higher for mercaptopurine formulation than for azathioprine formulation (1950 vs. 1056, P = 0.04). 5-Aminosalicylic acid use: 6-tioguanine nucleotides levels did not differ based on concomitant 5-aminosalicylic acid use. However, 5-aminosalicylic acid use did result in higher adjusted mean 6-methylmercaptopurine levels: 2078 on 5-aminosalicylic acid vs. 991 off 5-aminosalicylic acid (P = 0.004).
  
  
  CONCLUSIONS
  (i) Azathioprine may have metabolic benefits by achieving a correlation of dose with 6-tioguanine nucleotides levels and by leading to lower mean 6-methylmercaptopurine levels. (ii) 5-aminosalicylic acid use does not significantly impact 6-tioguanine levels and may lead to higher 6-methylmercaptopurine levels.
authors.affiliation: Department of Gastroenterology and Hepatology, Center for Inflammatory Bowel Disease, Cleveland Clinic Foundation, OH 44195, USA. stevent@ccf.org
authors.forename: T
authors.initials: T
authors.lastname: Stevens
authors.forename: J P
authors.initials: JP
authors.lastname: Achkar
authors.forename: K
authors.initials: K
authors.lastname: Easley
authors.forename: A
authors.initials: A
authors.lastname: Brzezinski
authors.forename: B
authors.initials: B
authors.lastname: Lashner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000636:Aminosalicylic Acids / Q000627:therapeutic use; D000963:Antimetabolites / Q000008:administration & dosage / Q000737:chemistry*; D001379:Azathioprine / Q000008:administration & dosage / Q000737:chemistry*; D002626:Chemistry, Pharmaceutical; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000188:drug therapy* / Q000378:metabolism; D008297:Male; D015122:Mercaptopurine / Q000378:metabolism*; D008875:Middle Aged; D012044:Regression Analysis
chemical_list: D000636:Aminosalicylic Acids; D000963:Antimetabolites; D015122:Mercaptopurine; D001379:Azathioprine