Allopurinol in addition to 5-aminosalicylic acid based drugs for the maintenance treatment of ulcerative colitis

Background: To investigate the value of combined treatment with allopurinol and 5-aminosalicylic (5-ASA) based drugs as maintenance treatment for ulcerative colitis (UC). Methods: 199 patients with UC in remission but with active disease during the preceding 3 years were included. Allopurinol 100 mg twice daily or placebo was added to the 5-ASA based maintenance treatment. Clinical and endoscopic follow up was performed after 1, 6 and 12 months. Results: Intention-to-treat analysis after 6 and 12 months showed similar results in both groups. A log-rank test showed that 77% in the allopurinol compared to 59% in the placebo group were still in remission after 6 months (P = 0.0083) and 62% and 53% after 12 months, respectively (P = 0.0936). This was mainly due to a higher than expected number of relapses during the first 3 months in the placebo group. After the first 3 months, the rate of relapse in each group was similar. Conclusions: It appears possible that allopurinol in combination with 5-ASA is better than 5-ASA alone for a 6-month, but not a 12-month period. This has to be verified in further dose-ranging studies.