IBS - Irritable Bowel SyndromeEarly Phase 1NCT06684470
Novel Pilot Study to Treat Symptoms of IBS With Diarrhea Using Combination Therapy of a Low-FODMAP Diet and a Neuromodulator
A Early Phase 1 study testing Mirtazapine in people with IBS - Irritable Bowel Syndrome and Diarrhea, run by Mayo Clinic at 1 site in United States.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- IBS - Irritable Bowel Syndrome, Diarrhea
- What is being tested?
- Mirtazapine
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 20 participants
- Where
- 1 siteUnited States
- Study dates
- 19 Dec 2024to 19 Dec 2026
- Phase
- Early Phase 1
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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
Who cannot join
- 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
Show all 10Show fewer
- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
Mayo Clinic
Jacksonville, Florida, 32224
Jessica C Petrov, M.D., 904-953-6970, researchparticipantadvocate@mayo.edu
Brian Lacy, M.D.
About this study
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.
Read the detailed description
We hypothesize that adult patients with IBS-D treated with a combination of a low FODMAP diet and mirtazapine will have a greater improvement in global IBS symptoms including abdominal pain and diarrhea in addition to improved quality of life compared to those treated with a low-FODMAP diet only. Global improvement in IBS symptoms will be evaluated using the validated IBS-SSS questionnaire. We will evaluate changes in quality of life using a validated IBS-QoL questionnaire. We will assess the improvement in abdominal pain using a numerical rating system and assess improvements in diarrhea using the Bristol stool form scale. We will assess responses to bloating using a Mayo bloating questionnaire forms. We will assess improvement in diarrhea using the Bristol stool form scale.
Improvement in anxiety and any other descriptive information as provided by patients including patients reporting impression of overall severity of symptoms at the beginning, middle, and end of study.
Irritable bowel syndrome (IBS) is a common gastrointestinal (GI) disorder that affects up to 10% of the United States adult population. IBS is characterized by recurrent abdominal pain and altered bowel habits, diagnosed using the Rome IV criteria. Approximately one-third of all IBS patients are classified as having IBS with diarrhea (IBS-D), which has no validated treatment algorithm. The American College of Gastroenterology IBS guideline recommends the low-FODMAP (fermentable oligo-, di-, monosaccharide, and polyol) diet as a safe and modestly effective treatment. An analysis of 7 randomized, controlled trials found that the low-FODMAP diet was associated with an improvement in global IBS symptoms. However, despite following the low-FODMAP diet, many patients have persistent abdominal pain, which can be difficult to treat. The mechanisms underlying chronic abdominal pain in patients with IBS are unknown, although visceral and central hypersensitivity are thought to play a role. No medication is FDA-approved for the treatment of abdominal pain in IBS. Mirtazapine is an atypical antidepressant that acts on several classes of receptors. In a small open-label study mirtazapine improved IBS-D symptoms, including abdominal pain.
- Conditions
- IBS - Irritable Bowel Syndrome, Diarrhea
- Being tested
- Mirtazapine, Placebo
- Keywords
- Diarrhea, IBS, Irritable Bowel Syndrome
- Medical subject headings
- Irritable Bowel Syndrome, Diarrhea
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
MirtazapineDrug
Also called Remeron
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.
PlaceboOther
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.
| Study group | Role | What they receive |
|---|---|---|
| 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. Receives: 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. Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Resolution of Irritable Bowel Syndrome
Evaluate global improvement in IBS symptoms using the validated IBS-SSS
Measured: 49 days
Abdominal Pain Score
Assess improvement in abdominal pain using a numerical rating system
Measured: 49 days
Stool Form Scale
Assess improvement in diarrhea using the Bristol stool form scale
Measured: 49 days
Mayo Bloating Scale
Assess response to bloating using a validated Mayo bloating questionnaire
Measured: 49 days
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Nov 2024
- Study start19 Dec 2024
- Primary completion19 Dec 2026 (estimated)
- Study completion19 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for IBS - Irritable Bowel SyndromeStudies of the same condition, open and under way.
- More trials run by Mayo ClinicThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Early Phase 1
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Mayo Clinic
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Brian Lacy, Mayo Clinic
- Investigators
- Brian E Lacy, MD, Principal investigator, Mayo Clinic
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06684470
- Sponsor's protocol ID
- 23-011874
- Status last verified
- Dec 2025
- First submitted
- 9 Nov 2024
- Last updated
- 18 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 18 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Novel Pilot Study to Treat Symptoms of IBS With Diarrhea Using Combination Therapy of a Low-FODMAP Diet and a Neuromodulator
- ClinicalTrials.gov ID
- NCT06684470
- Acronym / sponsor ID
- 23-011874
- Conditions
- IBS - Irritable Bowel Syndrome, Diarrhea
- Keywords
- Diarrhea, IBS, Irritable Bowel Syndrome
- Phase
- Early Phase 1
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 20 participants (estimated)
- Lead sponsor
- Mayo ClinicUniversity, hospital or other
- Study start
- 19 Dec 2024 (actual)
- Primary completion
- 19 Dec 2026 (estimated)
- Study completion
- 19 Dec 2026 (estimated)
- First posted
- 12 Nov 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
We hypothesize that adult patients with IBS-D treated with a combination of a low FODMAP diet and mirtazapine will have a greater improvement in global IBS symptoms including abdominal pain and diarrhea in addition to improved quality of life compared to those treated with a low-FODMAP diet only. Global improvement in IBS symptoms will be evaluated using the validated IBS-SSS questionnaire. We will evaluate changes in quality of life using a validated IBS-QoL questionnaire. We will assess the improvement in abdominal pain using a numerical rating system and assess improvements in diarrhea using the Bristol stool form scale. We will assess responses to bloating using a Mayo bloating questionnaire forms. We will assess improvement in diarrhea using the Bristol stool form scale.
Improvement in anxiety and any other descriptive information as provided by patients including patients reporting impression of overall severity of symptoms at the beginning, middle, and end of study.
Irritable bowel syndrome (IBS) is a common gastrointestinal (GI) disorder that affects up to 10% of the United States adult population. IBS is characterized by recurrent abdominal pain and altered bowel habits, diagnosed using the Rome IV criteria. Approximately one-third of all IBS patients are classified as having IBS with diarrhea (IBS-D), which has no validated treatment algorithm. The American College of Gastroenterology IBS guideline recommends the low-FODMAP (fermentable oligo-, di-, monosaccharide, and polyol) diet as a safe and modestly effective treatment. An analysis of 7 randomized, controlled trials found that the low-FODMAP diet was associated with an improvement in global IBS symptoms. However, despite following the low-FODMAP diet, many patients have persistent abdominal pain, which can be difficult to treat. The mechanisms underlying chronic abdominal pain in patients with IBS are unknown, although visceral and central hypersensitivity are thought to play a role. No medication is FDA-approved for the treatment of abdominal pain in IBS. Mirtazapine is an atypical antidepressant that acts on several classes of receptors. In a small open-label study mirtazapine improved IBS-D symptoms, including abdominal pain.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Double blind (participant, investigator)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Mirtazapine Group | Experimental | Drug: MirtazapineSubjects 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 Group | Placebo comparator | Other: PlaceboSubjects will present at Mayo Clinic through a doctor's appointment and a diagnosis of irritable bowel syndrome will be receiving placebo by pill form. |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Participants must meet all of the inclusion criteria to participate in this study:
Key exclusion criteria (10 listed)
- All candidates meeting any of the below exclusion criteria at baseline will be excluded from study participation:
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| MirtazapineAlso: Remeronmirtazapine 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. | Drug | Mirtazapine Group |
| PlaceboPlacebo 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. | Other | Placebo Group |
Primary outcome
Resolution of Irritable Bowel Syndrome
Time frame: 49 days
Evaluate global improvement in IBS symptoms using the validated IBS-SSS
Abdominal Pain Score
Time frame: 49 days
Assess improvement in abdominal pain using a numerical rating system
Stool Form Scale
Time frame: 49 days
Assess improvement in diarrhea using the Bristol stool form scale
Mayo Bloating Scale
Time frame: 49 days
Assess response to bloating using a validated Mayo bloating questionnaire
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 18 Dec 2025.
- Individual participant dataSharing planned: No
Related trials for IBS - Irritable Bowel Syndrome
RecruitingObservational study
Abdominal Symptoms and Rosacea: An Observational Study on the Association Between Irritable Bowel Syndrome (IBS) and the Gut-Skin Axis
IBS (Irritable Bowel Syndrome), Rosacea
Recruiting
Stress Reduction and Lifestyle Modification in Irritable Bowel Syndrome Patients
Irritable Bowel Syndrome
Recruiting
Exercise Interventions and Dietary Advice in Fibromyalgia and IBS
Fibromyalgia, Irritable Bowel Syndrome
RecruitingPhase 2
A Study of Brenipatide (LY3537031) in Participants With Irritable Bowel Syndrome-Constipation (IBS-C)
Irritable Bowel Syndrome, Constipation
RecruitingPhase 2
A Study of Brenipatide (LY3537031) in Participants With Irritable Bowel Syndrome-Diarrhea (IBS-D)
Irritable Bowel Syndrome, Diarrhea
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Brian E Lacy, MD principal investigator
Mayo Clinic
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Early Phase 1 study testing Mirtazapine in people with IBS - Irritable Bowel Syndrome and Diarrhea, run by Mayo Clinic at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 18 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Early Phase 1 (sometimes called Phase 0) studies give a very small amount of a treatment to a few people, mainly to see how the body handles it.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Jessica C Petrov, MD (904-953-2000, Petrov.Jessica@mayo.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Resolution of Irritable Bowel Syndrome (time frame: 49 days). The study lists 4 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 18 Dec 2025.