Azathioprine in ulcerative colitis: Why, when, how and how long to use it

Ulcerative colitis (UC) is a lifelong, immune-mediated inflammatory condition of the colonic mucosa characterized by a relapsing and remitting course. The mainstay of treatment used to be the 5-aminosalicylates (5-ASA) and corticosteroids. Nevertheless, some patients are unable to discontinue or reduce the steroid dosage and are exposed to a number of side effects. The efficacy of thiopurines is well proven in inflammatory bowel disease (IBD); azathioprine (AZA) is considered the first-line immunosuppressant with a steroid-sparing effect in UC patients with steroid dependence or resistance. Success rates of 70% occur in induction therapy with AZA and 6-mercaptopurine (MP) in UC with a number-needed-to-treat (NNT) to avoid recurrence (with AZA/MP, as compared with placebo) of 5 and absolute risk of reduction of 23%. Thus, AZA and MP are an effective therapeutic option in inducing and maintaining remission for UC patients who failed to improve or who do not tolerate 5-ASA or corticosteroids. Drug Dev Res 72:733738, 2011. (C) 2011 Wiley Periodicals, Inc.