[Is there any interest to dose the azathioprine's metabolites during inflammatory bowel diseases?].

The objective of our work is to search if there is a relation between azathioprine's metabolites (6-thioguanines nucleotides and 6-methyl mercaptopurines) and clinical efficacy and adverse effects of azathioprine in inflammatory bowel disease population. We included patients with Crohn's disease or ulcerative colitis (UC) treated by azathioprine for a duration more than 1 year. Each patient had a dosage of azathioprine metabolites. We included 43 Crohn's disease patients and 7 UC. Azathioprine was indicated for steroid dependancy in 23 cases, to prevent post-operative recurrence in 10 cases, to maintain clinical remission obtained by medical treatment in 17 patients. A clinical response to azathioprine (obtention of remission, absence of recurrence during the follow up) was observed in 34 patients. Our work confirms the relation between the doses of azathioprine metabolites and the myelotoxicity due to this molecule.