Antibiotic treatment of Crohn's disease: results of a multicentre, double blind, randomized, placebo-controlled trial with rifaximin

Background: Clinicians often employ antibiotics in Crohn's disease. Rifaximin is active against bacteria frequently found in the intestinal mucosa of Crohn's disease patients. Aim: To evaluate the difference in efficacy between once and twice/daily oral administration of rifaximin and placebo in the treatment of active Crohn's disease. Methods: We enrolled 83 patients with mild-to-moderate Crohn's disease and randomized to three treatments for 12 weeks: Group A (rifaximin 800 mg o.d. + placebo), Group B (rifaximin 800 mg b.d.) and Group C (placebo b.d.). Results: Clinical remission was achieved by 52% of Group B, 32% (A) and 33% (C). Clinical response was seen in 67% (B), 48% (A) and 41% (C), without reaching a statistically significant difference. Treatment failures were: 4% (B), 12% (A) and 33% (C), (P = 0.010). Remission and response rates of rifaximin 800 mg b.d. were significantly higher than those of placebo and rifaximin 800 mg o.d. in patients with elevated C reactive protein values (P < 0.05). Conclusions: Rifaximin 800 mg b.d. was superior to placebo in inducing clinical remission of active Crohn's disease. Although this difference was not statistically significant, the number of the failures in the placebo group was significantly higher than those who received rifaximin 800 mg b.d.