Using hydrogen breath tests to predict response to rifaximin in IBS-D patients

The Role of Breath Testing in Enriching the Likelihood of Response to Rifaximin in Patients With Diarrhea IBS

Phase 4 Interventional University of Michigan · NCT03729271

This study is testing if hydrogen breath tests can help find out which patients with diarrhea-predominant IBS will benefit from a treatment called rifaximin.

Quick facts

PhasePhase 4
Study typeInterventional
Enrollment110 (estimated)
Ages18 Years to 80 Years
SexAll
SponsorUniversity of Michigan Academic / other
Locations1 site (Ann Arbor, Michigan)
Trial IDNCT03729271 on ClinicalTrials.gov

What this trial studies

This study aims to improve treatment for patients suffering from diarrhea-predominant Irritable Bowel Syndrome (IBS-D) by using hydrogen breath testing to identify those who are more likely to respond positively to rifaximin. Participants will undergo a one-week screening period, during which they will complete daily surveys and then receive a 14-day course of rifaximin. Additionally, glucose and lactulose hydrogen breath tests will be conducted before and after treatment, along with the collection of biological samples. The study seeks to enroll 110 patients after screening 210 to assess the effectiveness of this approach.

Who should consider this trial

Good fit: Ideal candidates for this study are adults diagnosed with diarrhea-predominant IBS according to the Rome IV criteria.

Not a fit: Patients with conditions such as inflammatory bowel disease, diabetes, or recent gastrointestinal surgery may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to more personalized and effective treatment options for patients with IBS-D.

How similar studies have performed: Other studies have explored the use of breath testing in gastrointestinal conditions, but this specific approach to predict rifaximin response in IBS-D is novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* IBS-D (Rome IV Diagnostic Criteria)
* Diary compliance for at least 5 days and no rescue medications during baseline
* Appropriate levels of abdominal pain and diarrhea

Exclusion Criteria:

* Pregnant women or planning on becoming pregnant while in the study, or lactating women while in the study
* Inflammatory bowel disease, diabetes mellitus, systemic sclerosis, or celiac disease
* Active gastrointestinal or hematological malignancy which requires ongoing treatment
* Surgery to the GI tract in the past 3 months
* Gastrointestinal infection or diverticulitis in the past 3 months
* Severe hepatic impairment
* Any use of antibiotics in the past month
* Current use of probiotics
* Any history of allergies to rifaximin or its derivatives
* Any comitant use of P-glycoprotein inhibitors (for example. Cyclosporine)
* Known allergies to glucose or lactulose

Where this trial is running

Ann Arbor, Michigan

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Irritable Bowel SyndromeIrritable Bowel Syndrome With DiarrheaIBS
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.