Researchers at University of Leeds, funded by NIHR Health Technology Assessment, are looking for patients with stable Ulcerative Colitis who experience symptoms of diarrhoea, to take part in a study assessing the effectiveness of the low FODMAP diet, amitriptyline, loperamide and ondansetron.

Last reviewed July 2022

Background and study aims

Ulcerative colitis (UC) is a long-term condition where the colon and rectum become inflamed. The colon is the large intestine (bowel) and the rectum is the end of the bowel where stools are stored. Small ulcers can develop on the colon's lining, which can bleed and produce pus. There can also be chronic diarrhoea and cramping tummy pain. Some people with UC have ongoing chronic diarrhoea even when they have no sign of bowel inflammation and their disease is ‘stable’. This can have a huge physical and an emotional impact on these people. It causes discomfort and distress, reducing quality of life by impacting on their daily activities, psychological health and mood. There is currently no treatment for these people.

A potential approach may be to use existing treatments that work in other conditions, for example irritable bowel syndrome (IBS). There are important differences between UC and IBS, but people with IBS can also suffer with chronic diarrhoea and there are treatments available to help them with this particular symptom. In IBS, a diet low in poorly absorbed sugars (FODMAPs) and drugs like ondansetron (an anti-sickness drug), low-dose amitriptyline (an antidepressant drug, here used to slow gut transit), and loperamide (an anti-diarrhoeal drug) can all help treat diarrhoea and related tummy pain. This is because they all change bowel activity by slowing the flow of digested food down the gut. We want to find out if these treatments may safely help people with diarrhoea who have stable UC and currently have no other treatment options. 

More detailed technical information can be found on the trial website.

Who can participate?

People aged over 18 years with stable UC who have diarrhoea.

What does the study involve?

All participants will be provided with standard first-line dietary advice. People will also be given one of the following: a low FODMAP diet; ondansetron; low-dose amitriptyline; loperamide; or no additional treatment as a control group. A computer will randomly decide who gets which one. People will be asked to follow the diet or take the tablets for 6 months, in addition to their doctor’s usual treatment for UC. People will be aware of which treatment they get.

People will be followed up at 8 weeks and 6 months. Side effects and adherence to each treatment will be recorded as well as how many flare-ups people experience, whether usual treatment for UC has been changed, and whether surgery has been required. If someone experiences a flare whilst on the MODULATE trial, be reassured that they will be referred back to their usual doctor for treatment and will be withdrawn from the trial. 

What are the possible benefits and risks of participating?

Benefits - improvement in symptoms and quality of life for patients with stable UC and ongoing diarrhoea, fewer hospital visits, should help clinicians, patients and health service planners to make better-informed decisions regarding the management of diarrhoea in patients with stable UC in secondary care.
Risks - side effects associated with the drugs (although thought to be at a reduced rate due to the lower dose used).

How can I take part?

Excitingly, this study has recently opened to recruitment in a few hospitals – with more to follow in the coming months. The study team will shortly be launching a self-screening questionnaire on their website and you’ll be able to use this to check if any study sites are open near you and if you may be eligible to take part. If you are interested and would like more information about the study, please contact


Opportunity posted on 18 March 2020

This research study is NOT funded or organised by Crohn's & Colitis UK and, therefore, we cannot take responsibility for your involvement in the research. It is a patient’s choice to take part.

Want to get involved in research?

The best quality research happens when people with Crohn's and Colitis are involved, and you can make a difference at every stage of research.


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