Abstract: Over the past 25 years thiopurine-based therapy has assumed a pivotal role in the care of patients with inflammatory bowel diseases [IBDs]. Key clinical trials in ulcerative colitis [UC] and Crohn’s disease [CD] have demonstrated the efficacy of thiopurines in maintaining long-term remission in about 60% in UC1 and 42–30% in CD.2–4 While earlier studies have focused on their steroid-sparing effect,5 later studies performed in children6 and adults indirectly showed a modest role in modifying disease course and preventing or delaying intestinal resection in CD,7,8, although these observations were not universal.9 Thiopurines have also shown efficacy in reducing post-operative recurrence for up to 2 years in CD10,11 and possibly in reducing clinical recurrence and avoiding repeat surgery in this setting.12 Indeed, current guidelines incorporate thiopurines in the maintenance of remission in moderate or steroid-dependent CD and UC13,14 and for the prevention of post-operative recurrence in CD.15 Finally, thiopurines have been shown to reduce immunogenicity towards biologics when introduced both before,16 concurrently17 or even after formation of anti-drug antibodies.18 However, there are several concerns regarding the use of thiopurines in both short- and long-term IBD therapy. First, thiopurine monotherapy has no role in the treatment of active inflammatory flares,1 most probably due to their slow onset of action.19 In addition, …
Corresponding author: Yehuda Chowers, MD, Department of Gastroenterology, Rambam Health Care Campus, P.O.B 9601, Bat Galim, Haifa, Israel. Tel.: +972-4-7773608; fax: +972-4-7773058; email: y_chowers{at}rambam.health.gov.il