Recruiting
Early Phase 1

Low-FODMAP Diet & Neuromodulator

Sponsor:

Mayo Clinic

Code:

NCT06684470

Conditions

IBS - Irritable Bowel Syndrome

Diarrhea

Eligibility Criteria

Sex: All

Age: 18 - 70

Healthy Volunteers: Not accepted

Interventions

Mirtazapine

Placebo

Study Details

Brief summary:

The purpose of this research is to study the added benefit of treating IBS symptoms with a medication called mirtazapine in treating IBS symptoms when paired with a low-FODMAP diet compared to a low-FODMAP diet alone. FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. These are short-chain carbohydrates that can cause digestive distress in some people.

You have been asked to take part in this research because you have symptoms of diarrhea-predominant irritable bowel syndrome that may respond to treatment with a combination of a medication called mirtazapine and a low-FODMAP diet.

Conditions

IBS - Irritable Bowel Syndrome

Diarrhea

Study ID

NCT06684470

Start date

Dec 19, 2024

Status verified date

Dec, 2025

Completion date

Dec 19, 2026

Anticipated

Primary completion date

Dec 19, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 70

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • Participants must meet all of the inclusion criteria to participate in this study:

  • Adults (ages 18-70)
  • Score of >175 on the IBS-SSS questionnaire
  • Must meet Rome IV criteria for IBS-D
  • If subject is of reproductive capability a negative urine pregnancy test must be available prior to entering the study
  • Ability to understand study procedures and to comply with them for the entire length of the study

Exclusion Criteria:

  • All candidates meeting any of the below exclusion criteria at baseline will be excluded from study participation:

  • Score of < 175 on the IBS-SSS
  • Prior diagnoses of: known celiac disease, small intestinal bacterial overgrowth, inflammatory bowel disease, or microscopic colitis
  • Ongoing significant anxiety or depression
  • A history of a known side effect to mirtazapine
  • Prior treatment with a low FODMAP diet or mirtazapine without clinical benefit
  • Active alcohol or drug abuse
  • Inability to read or understand the consent form
  • Any other medical or psychological reason that would prevent active participation in a research study
  • Pregnant females

Study Design

Enrollment

20 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Mirtazapine Group

Subjects will present at Mayo Clinic through a doctor's appointment and a diagnosis of irritable bowel syndrome will be receiving mirtazapine by pill form.

placebo comparator: Placebo Group

Subjects will present at Mayo Clinic through a doctor's appointment and a diagnosis of irritable bowel syndrome will be receiving placebo by pill form.

Interventions

Mirtazapine

mirtazapine will be told to use 1 pill 1 hour before bedtime for the first week (7.5 mg po q.h.s.), 2 pills before bedtime during the second week of therapy (15 mg po q.h.s.), 3 pills (22.5 mg po q.h.s.) 1 hour before bedtime for the third week, and 4 pills (30 mg po q.h.s.) 1 hour prior to bedtime for the remainder of the study.

Placebo

Placebo will be told to use 1 pill 1 hour before bedtime for the first week (7.5 mg po q.h.s.), 2 pills before bedtime during the second week of therapy (15 mg po q.h.s.), 3 pills (22.5 mg po q.h.s.) 1 hour before bedtime for the third week, and 4 pills (30 mg po q.h.s.) 1 hour prior to bedtime for the remainder of the study.

Primary outcome measure

  • Resolution of Irritable Bowel Syndrome [ Time Frame: 49 days ]
  • Abdominal Pain Score [ Time Frame: 49 days ]
  • Stool Form Scale [ Time Frame: 49 days ]
  • Mayo Bloating Scale [ Time Frame: 49 days ]

Central Contacts and Locations

Central contacts

Jessica C Petrov, MD

904-953-2000Petrov.Jessica@mayo.edu

Locations

Mayo Clinic

Recruiting

Jacksonville, Florida, United States, 32224

Contacts

Jessica C Petrov, M.D.

904-953-6970researchparticipantadvocate@mayo.edu

Principal Investigator:

Brian Lacy, M.D.

More Information

Sponsor

Mayo Clinic

Last update posted

Dec 18, 2025

Last verified

Dec, 2025

Keywords

  • Diarrhea
  • IBS
  • Irritable Bowel Syndrome

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Mayo Clinic on 2025-12-18.