title: Rifaximin therapy for patients with irritable bowel syndrome without constipation.
abstract: BACKGROUND
  Evidence suggests that gut flora may play an important role in the pathophysiology of the irritable bowel syndrome (IBS). We evaluated rifaximin, a minimally absorbed antibiotic, as treatment for IBS.
  
  
  METHODS
  In two identically designed, phase 3, double-blind, placebo-controlled trials (TARGET 1 and TARGET 2), patients who had IBS without constipation were randomly assigned to either rifaximin at a dose of 550 mg or placebo, three times daily for 2 weeks, and were followed for an additional 10 weeks. The primary end point, the proportion of patients who had adequate relief of global IBS symptoms, and the key secondary end point, the proportion of patients who had adequate relief of IBS-related bloating, were assessed weekly. Adequate relief was defined as self-reported relief of symptoms for at least 2 of the first 4 weeks after treatment. Other secondary end points included the percentage of patients who had a response to treatment as assessed by daily self-ratings of global IBS symptoms and individual symptoms of bloating, abdominal pain, and stool consistency during the 4 weeks after treatment and during the entire 3 months of the study.
  
  
  RESULTS
  Significantly more patients in the rifaximin group than in the placebo group had adequate relief of global IBS symptoms during the first 4 weeks after treatment (40.8% vs. 31.2%, P=0.01, in TARGET 1; 40.6% vs. 32.2%, P=0.03, in TARGET 2; 40.7% vs. 31.7%, P<0.001, in the two studies combined). Similarly, more patients in the rifaximin group than in the placebo group had adequate relief of bloating (39.5% vs. 28.7%, P=0.005, in TARGET 1; 41.0% vs. 31.9%, P=0.02, in TARGET 2; 40.2% vs. 30.3%, P<0.001, in the two studies combined). In addition, significantly more patients in the rifaximin group had a response to treatment as assessed by daily ratings of IBS symptoms, bloating, abdominal pain, and stool consistency. The incidence of adverse events was similar in the two groups.
  
  
  CONCLUSIONS
  Among patients who had IBS without constipation, treatment with rifaximin for 2 weeks provided significant relief of IBS symptoms, bloating, abdominal pain, and loose or watery stools. (Funded by Salix Pharmaceuticals; ClinicalTrials.gov numbers, NCT00731679 and NCT00724126.).
authors.affiliation: Cedars-Sinai Medical Center, Los Angeles, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Pimentel
authors.forename: Anthony
authors.initials: A
authors.lastname: Lembo
authors.forename: William D
authors.initials: WD
authors.lastname: Chey
authors.forename: Salam
authors.initials: S
authors.lastname: Zakko
authors.forename: Yehuda
authors.initials: Y
authors.lastname: Ringel
authors.forename: Jing
authors.initials: J
authors.lastname: Yu
authors.forename: Shadreck M
authors.initials: SM
authors.lastname: Mareya
authors.forename: Audrey L
authors.initials: AL
authors.lastname: Shaw
authors.forename: Enoch
authors.initials: E
authors.lastname: Bortey
authors.forename: William P
authors.initials: WP
authors.lastname: Forbes
mesh_terms: D015746:Abdominal Pain / Q000188:drug therapy / Q000209:etiology; D000368:Aged; D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000627:therapeutic use*; D003967:Diarrhea / Q000188:drug therapy / Q000209:etiology; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000150:complications / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D012294:Rifamycins / Q000009:adverse effects / Q000627:therapeutic use*; D000078262:Rifaximin
chemical_list: D000900:Anti-Bacterial Agents; D012294:Rifamycins; D000078262:Rifaximin