Novel Pilot Study to Treat Symptoms of IBS With Diarrhea Using Combination Therapy of a Low-FODMAP Diet and a Neuromodulator

NCT06684470 | Recruiting Early Phase 1 FDA Drug

• 1 other identifier: 23-011874
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

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

Keywords

Diarrhea; IBS; Irritable Bowel Syndrome

Outcome Measures

Primary Outcomes (4)

• Resolution of Irritable Bowel Syndrome

  Evaluate global improvement in IBS symptoms using the validated IBS-SSS

  49 days

• Abdominal Pain Score

  Assess improvement in abdominal pain using a numerical rating system

  49 days

• Stool Form Scale

  Assess improvement in diarrhea using the Bristol stool form scale

  49 days

• Mayo Bloating Scale

  Assess response to bloating using a validated Mayo bloating questionnaire

  49 days

Study Arms (2)

Mirtazapine Group

EXPERIMENTAL

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.

Drug: Mirtazapine

Placebo Group

PLACEBO COMPARATOR

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.

Other: Placebo

Interventions

Mirtazapine DRUG

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.

Also known as: Remeron

Mirtazapine Group

Placebo OTHER

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.

Placebo Group

Eligibility Criteria

• Age: 18 Years - 70 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Mayo Clinic: lead

Study Sites (1)

Mayo Clinic

Jacksonville, Florida, 32224, United States

RECRUITING

MeSH Terms

Conditions

Irritable Bowel Syndrome; Diarrhea

Interventions

Mirtazapine

Condition Hierarchy (Ancestors)

Colonic Diseases, Functional; Colonic Diseases; Intestinal Diseases; Gastrointestinal Diseases; Digestive System Diseases; Signs and Symptoms, Digestive; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Intervention Hierarchy (Ancestors)

Dibenzazepines; Heterocyclic Compounds, 3-Ring; Heterocyclic Compounds, Fused-Ring; Heterocyclic Compounds

Study Officials

• Brian E Lacy, MD

  Mayo Clinic

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Jessica C Petrov, MD

CONTACT

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

Study Design

• Study Type: interventional
• Phase: early phase 1
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: November 9, 2024
• First Posted: November 12, 2024
• Study Start: December 19, 2024
• Primary Completion (Estimated): December 19, 2026
• Study Completion (Estimated): December 19, 2026
• Last Updated: December 18, 2025

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)