title: A randomised trial of ondansetron for the treatment of irritable bowel syndrome with diarrhoea.
abstract: BACKGROUND
  Irritable bowel syndrome with diarrhoea (IBS-D) is particularly debilitating due to urgency and episodic incontinence. Some 5-hydroxytryptamine 3 (5-HT3) receptor antagonists (5-HT3RAs) have proven effective but have serious side effects. Ondansetron, also a 5-HT3RA, has been widely used as an antiemetic with an excellent safety record for over two decades. Our aim was to assess its effectiveness in IBS-D.
  
  
  METHODS
  120 patients meeting Rome III criteria for IBS-D entered a randomised, double-blind, placebo-controlled crossover study of 5 weeks of ondansetron 4 mg versus placebo with dose titration allowed, up to two tablets three times daily in the first 3 weeks. Patients completed daily diaries documenting stool consistency using the Bristol Stool Form score. Gut transit was measured in the last week of each treatment. The primary endpoint was average stool consistency in the last 2 weeks of treatment.
  
  
  RESULTS
  Ondansetron significantly improved stool consistency (mean difference in stool form between ondansetron and placebo -0.9, 95% CI -1.1 to -0.6, p<0.001). Compared with placebo, patients on ondansetron experienced fewer days with urgency (p<0.001), lower urgency scores (p<0.001), reduced frequency of defaecation (p=0.002) and less bloating (p=0.002), although pain scores did not change significantly. IBS symptom severity score fell more with ondansetron than placebo (83±9.8 vs 37±9.7, p=0.001). 65% reported adequate relief with ondansetron but not placebo compared with 14% reporting relief with placebo but not ondansetron, relative risk 4.7, 95% CI 2.6 to 8.5, p<0.001.
  
  
  CONCLUSIONS
  Ondansetron relieves some of the most intrusive symptoms of IBS-D, namely loose stools, frequency and urgency.
authors: Nottingham Digestive Diseases Biomedical Research Unit, Queens Medical Centre, Nottingham, UK.
authors: Klara
authors: K
authors: Garsed
authors: Nottingham Digestive Diseases Biomedical Research Unit, Queens Medical Centre, Nottingham, UK.
authors: Julia
authors: J
authors: Chernova
authors: Neurogastroenterology Unit, Wythenshawe Hospital, Manchester, UK.
authors: Margaret
authors: M
authors: Hastings
authors: Nottingham Digestive Diseases Biomedical Research Unit, Queens Medical Centre, Nottingham, UK.
authors: Ching
authors: C
authors: Lam
authors: Sir Peter Mansfield Magnetic Resonance Imaging Centre, University of Nottingham, Nottingham, UK.
authors: Luca
authors: L
authors: Marciani
authors: Nottingham Digestive Diseases Biomedical Research Unit, Queens Medical Centre, Nottingham, UK.
authors: Gulzar
authors: G
authors: Singh
authors: Department of Molecular Medicine, School of Surgical and Medical Sciences, University of Nottingham, Nottingham, UK.
authors: Amanda
authors: A
authors: Henry
authors: Department of Molecular Medicine, School of Surgical and Medical Sciences, University of Nottingham, Nottingham, UK.
authors: Ian
authors: I
authors: Hall
authors: Neurogastroenterology Unit, Wythenshawe Hospital, Manchester, UK.
authors: Peter
authors: P
authors: Whorwell
authors: Nottingham Digestive Diseases Biomedical Research Unit, Queens Medical Centre, Nottingham, UK.
authors: Robin
authors: R
authors: Spiller
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D003967:Diarrhea / Q000188:drug therapy*; D004311:Double-Blind Method; D005243:Feces; D005260:Female; D006801:Humans; D043183:Irritable Bowel Syndrome / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D017294:Ondansetron / Q000009:adverse effects / Q000627:therapeutic use*; D012702:Serotonin Antagonists / Q000009:adverse effects / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D012702:Serotonin Antagonists; D017294:Ondansetron
keywords: Clinical Trials; Irritable Bowel Syndrome; Serotonin