Study to Assess the Efficacy and Safety of Rifaximin Administered BID in the Treatment of Patients With Diarrhea-Associated Irritable Bowel Syndrome
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This is placebo-controlled study of three rifaximin doses in patients with DIBS. Subjects will be randomized to receive daily doses of placebo BID, rifaximin 275 mg BID, rifaximin 550 mg BID, or 1100 mg BID for 14 days. These four groups will subsequently receive an additional two weeks of placebo for a total of 4 weeks of treatment. A fifth group of subjects will receive rifaximin 550 mg BID for a period of 28 days. Subjects who successfully respond to treatment at the end of the 28-day Treatment Phase will be followed in a Post-treatment Phase that includes study visits during Weeks 6, 8, 12 and 16. Subjects who relapse during the Post-treatment Phase will be discontinued from the study.
Condition or disease
Irritable Bowel Syndrome
While IBS is one of the most common chronic medical conditions the etiology of IBS is unknown. Although not a life-threatening illness, IBS is considered to be a serious condition that has a substantial impact on a subject's day-to-day function. IBS is characterized by abdominal pain and altered bowel habits, including diarrhea, constipation, or alternating diarrhea and constipation. Symptoms are typically intermittent but may be continuous.
Multicenter, Randomized, Double-Blind, Placebo-Controlled Study to Assess The Efficacy and Safety of Three Different Doses (275, 550 AND 1100 MG) of Rifaximin Administered BID For Either Two or Four Weeks in The Treatment of Patients With Diarrhea-Associated Irritable Bowel Syndrome
Study Start Date
Primary Completion Date
Study Completion Date
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The primary objective of this trial is to evaluate the efficacy of a 14-day course of oral rifaximin at 550 mg BID versus placebo in providing adequate relief from Diarrhea-associated IBS (DIBS) symptoms.
Secondary Outcome Measures
To evaluate the dose-response relationship of placebo administered for 28 days and rifaximin administered at 275 mg BID, 550 mg BID, or 1100 mg BID for 14 days;
to evaluate the efficacy of 550 mg BID for 4 weeks to determine if there are any differences when treatment is extended for an additional 2-week period when compared to a similar dosing regimen for 2 weeks;
to evaluate the durability of response over a 12-week Post-treatment Phase in subjects with DIBS who achieved a response during the acute Treatment Phase of the study.
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Ages Eligible for Study:
18 Years and older (Adult, Senior)
Sexes Eligible for Study:
Accepts Healthy Volunteers:
Male or female subject 18 years of age or older.
Irritable bowel syndrome confirmed by the Rome II Criteria
Lower endoscopic examination that demonstrates normal colonic anatomy
Subject has exclusively constipation-predominant IBS (CIBS) that is characterized by < 3 bowel movements/week or hard and lumpy stools.
Subject has alternating IBS, but is currently presenting with constipation associated IBS symptoms.
Subject has had adequate control of their DIBS and their symptom of bloating the week preceding the screening visit or at the time of randomization. Bloating includes the following symptoms: abdominal fullness, bloating, gas, or swelling.
Subjects has a positive stool culture for O & P (ovum and parasite) and/or Clostridium difficile
Subject has failed to record 2 negative weekly global assessments during the past 10 days prior to randomization.