Home › NCT03687814

Low FODMAP Plus PEG 3350 for the Treatment of Patients with Irritable Bowel Syndrome-Constipation

Who can join

Ages 18 and older · All sexes

Inclusion Criteria:

1\. Subjects aged 18 and older meeting the Rome IV criteria for IBS-C\*:

• Recurrent abdominal pain, on average, at least 1 day/week in the last 3 months, associated with two or more of the following:

1. related to defecation
2. associated with a change in the frequency of stool (reduction of stools)
3. associated with a change in the form of stool (hard or lumpy stools) AND \>25% hard stools and \<25% loose stools \* Criteria fulfilled for the last 3 months

Exclusion Criteria:

* any other IBS subtype other than IBS-C
* \>3 spontaneous bowel movements during the last 7 days of run-in
* Have cognitive dysfunction or unable to understand or provide written informed consent
* Pregnancy (evaluated by self-report)
* Comorbid medical problems that may affect gastrointestinal transit or motility:
* Inflammatory bowel disease
* Extra-intestinal disease known to affect the gastrointestinal system (i.e., scleroderma, unstable thyroid disease, etc.)
* Severe renal or hepatic disease
* Previous abdominal surgery other than appendectomy, cholecystectomy, and gynecologic/urologic surgery if performed more than six months prior to enrollment
* Previous treatment with the low FODMAP diet under a dietician guidance
* Concurrent medications not permitted including probiotics, antibiotics, prescription or over-the-counter medication for IBS, and narcotics
* New antidepressant use (less than 3 months on stable dose)
* Active participation in another form of dietary therapy

About the study

Consecutive patients with Irritable Bowel Syndrome with Constipation (IBS-C) will be recruited from the outpatient clinics of the University of Michigan Health System. Eligible patients will be asked to participate in a study that will test the efficacy the PEG 3350 + a diet low in fermentable oligo, di, monosaccharides, and polyols (FODMAP) vs. PEG 3350 plus sham diet. Blinding dietary advice trials is challenging and therefore the sham diet was based on the criteria set forth by Staudacher et al. which emphasizes that the diet must give the impression that is the true intervention diet with similar restrictions, modifications, and time intensity without impacting the intake of essential nutrients, fiber, and FODMAPs. An example of the sham diet's carbohydrates includes: apples, bananas, and pears, and wheat. Oranges, raspberries, strawberries and rice would not be allowed. Additionally, the physicians analyzing the data will be blinded as to which group the patients were randomized.

What is being tested

• Low FODMAP diet/PEG 3350 (other)
• sham diet/PEG 3350 (other)

Sponsor: University of Michigan · Participants: 78 · Started: Nov 8, 2018

Contact the study team

• Stacy Menees, MD, MS · Phone: 734-232-3739
• Amy Liu, BS · Phone: 734-647-4794

Official record on ClinicalTrials.gov — NCT03687814

Locations in the U.S.

From ClinicalTrials.gov, data retrieved Oct 1, 2026. Each study sets its own eligibility; the study team decides who can join.