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Be Part of Research - Trial Details - Ondansetron for Low Anterior Resection Syndrome after rectal cancer treatment

Ondansetron for Low Anterior Resection Syndrome after rectal cancer treatment

Stopped

Open to: All Genders

Age: Adult

Medical Conditions

Low anterior resection syndrome following rectal cancer treatment


This information is provided directly by researchers, and we recognise that it isn't always easy to understand. We are working with researchers to improve the accessibility of this information. In some summaries, you may come across links to external websites. These websites will have more information to help you better understand the study.


Rectal cancer is one of the most common cancers in the UK, and although chemo-radiotherapy and surgery are effective treatments, up to half of all patients report severe distressing problems after their treatment has finished. These include diarrhoea and problems with bowel control, ranging from needing to rush to the toilet (urgency), to complete bowel incontinence. This range of symptoms is known as “Low Anterior Resection Syndrome” (LARS) and can significantly affect quality of life. Unfortunately, at the moment, there are no effective treatments for LARS.

The symptoms of urgency and diarrhoea reported by LARS patients are similar to those in Irritable Bowel Syndrome (IBS). In IBS it has been shown that a cheap, widely available drug, called ondansetron. Ondansetron is normally used to treat nausea and vomiting and is effective and safe in treating diarrhoea and urgency.

The aim of this study is to find out if ondansetron helps resolve LARS symptoms.

Start dates may differ between countries and research sites. The research team are responsible for keeping the information up-to-date.  

The recruitment start and end dates are as follows:

01 Feb 2020 24 Apr 2025

To find out whether they are suitable to take part in the study, participants will first need to record details of symptoms and any medication taken for 2 weeks in a screening diary. Information in the screening diary will be reviewed by the research team who will confirm to the participant if they are eligible to take part.

Eligible participants will be allocated to one of two groups, with an equal chance of being in either group (like tossing a coin), so that half of the participants will receive ondansetron capsules and the other half will receive a placebo (this will look exactly the same as ondansetron but with no active ingredient). Neither the researchers nor the participants will know which capsules they are getting.

Participants will take ondansetron or placebo orally for 6 weeks, and complete a daily diary to record details on urgency, frequency, and consistency of their bowel movements, and any medications they have taken. Participants will also complete questionnaires about their bowel symptoms and quality of life, at the beginning and end of the trial.


Adult patients with LARS symptoms in from hospitals in England, at least 1 year after completion of all treatments for their rectal cancer

You can take part if:



You may not be able to take part if:


1. Clinical and radiological anastomotic leakage after rectal cancer surgery, defined as a defect of the intestinal wall at the anastomotic site (including suture and staple lines of neorectal reservoirs) leading to a communication between the intra- and extraluminal compartments2. Gastrectomy 3. Other known organic GI diseases (e.g. Crohn’s disease, ulcerative colitis, coeliac disease) 4. Untreated thyroid dysfunction 5. Taking other medications influencing colonic motility (e.g. opioids, cholinergic agents, prokinetics, metoclopramide, cisapride, etc.) which are likely to be stopped or changed during the course of the trial6. Lactose intolerance7. Known QTc interval ≥450 ms for men and ≥470 ms for women 8. Continuous use of ondansetron for >1 month within the past year9. Contraindications to ondansetron (e.g. concomitant use with apomorphine, hypersensitivity to any component of the preparation, rare hereditary problems of galactose intolerance, the Lapp lactase deficiency, or glucose-galactose malabsorption)10. Currently participating in any interventional phase of another clinical trial11. Pregnant or breastfeeding


Below are the locations for where you can take part in the trial. Please note that not all sites may be open.

  • University Hospital Southampton NHS Foundation Trust
    Mailpoint 18 Southampton General Hospital Tremona Road
    Southampton
    SO16 6YD
  • Shrewsbury And Telford Hospital NHS Trust
    Mytton Oak Road
    Shrewsbury
    SY3 8XQ
  • London North West University Healthcare NHS Trust
    Northwick Park Hospital Watford Road
    Harrow
    HA1 3UJ
  • Salisbury NHS Foundation Trust
    Salisbury District Hospital Odstock Road
    Salisbury
    SP2 8BJ
  • Hampshire Hospitals NHS Foundation Trust
    Aldermaston Road
    Basingstoke
    RG24 9NA
  • Nottingham University Hospitals NHS Trust
    Trust Headquarters Queens Medical Centre Derby Road
    Nottingham
    NG7 2UH

Taking part in the study may not directly benefit participants, but information from the study will help to improve the treatment of people that suffer from the symptoms of LARS in the future.
Ondansetron has been widely used for over 25 years to treat nausea. As with all medications, there is a small risk of side effects. At the doses used in the study, the main side effect is expected to be constipation. Other common side effects include feeling hot and/or headaches. Uncommon side effects include arrhythmias (irregular heartbeat), chest pain, hiccups, low blood pressure, movement disorders, oculogyric crisis (upward rolling of the eyes), and seizure. Rare side effects include dizziness, QT interval prolongation (a problem with the heart’s electrical activity), and vision disorders.


The study is sponsored by Nottingham University Hospitals NHS Trust and funded by National Institute for Health Research.




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Read full details for Trial ID: ISRCTN48772765

Or CPMS 44460

Last updated 09 May 2025

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