Irritable Bowel Syndrome (IBS) is a gastrointestinal syndrome characterized by chronic pain and irregular bowl movement with the absence of organ cause. IBS could be diarrhea-predominate or constipation-predominate. One of the pathophysiology that thought to cause IBS diarrhea-predominate (IBS-D) is a high level of serotonin especially after the meals. There are two type of serotonin that involve in the gastrointestinal system, type 3 (HT3) and type 4 (HT4). The purpose of this study is to evaluate the efficacy of ondansetron, which is a selective 5-HT3-receptor antagonist that have been used as antiemitc agent, in the treatment IBS-D.
Literature search strategy:
A literature search was conducted in Pubmed using the following MeSH terms: ondansetron, IBS, treatment. The drug terms were combined with the remaining terms with the boolean operator "and". This was then limited to the English language, last five years and human. A total of 2 articles was identified. Of these, 1 met the following criteria: randomized control trial and assessed the effectiveness of using ondansetron in the treatment of IBS-D. The other article was excluded because it was not relevant to the question.
A randomized trial of ondansetron for the treatment of irritable bowel syndrome with diarrhea, was a two-centre, double-blind, placebo controlled crossover study of ondansetron 4 mg/tablet versus placebo. The inclusion criteria of the study were age 18–75 years, IBS-D patients meeting the Rome III criteria, women of childbearing age should agree to have contraception during the study, no evidence of inflammatory bowel disease/microscopic colitis and able to give informed consent. The exclusion criteria were pregnancy or breast feeding, unwilling to stop antidiarrheal medications (loperamide or codeine phosphate), prior abdominal surgery other than appendectomy and cholecystectomy, being in another trial or being in the opinion of the investigator unsuitable.
The participant were divided in to two groups. First group received 5-weeks of oral ondansetron 4 mg tablets and the dose could be titrated to 2 tablet TID for the first 3weeks. Second group received placebo for the same 5 weeks. After that period there were a washout period for 2-3weeks, then each group received the opposite. The symptoms were assessed at the first visit to obtain a baseline, throughout the study and during the washout period to ensure symptoms had returned to baseline before starting the next treatment.
The primary endpoint was the stool form and secondary endpoints were pain perception, urgency of defecation, bloating, frequency of defecation per day, number of days per...