Katholieke Universiteit te Leuven
Leuven, Belgium
Not recruiting
Study on the Effects of Rifaximin on Stress and Fear Responses in Healthy Men
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What is this trial about?
A plain-language summary of the goals, design and what participants do
This clinical trial is focused on studying the effects of a medication called rifaximin on certain mental and physical responses in healthy men. The study involves healthy volunteers who do not have any intestinal or psychological issues. The main goal is to see if rifaximin, which is taken as a film-coated tablet, can change the gut bacteria in a way that might reduce reactions to stress and fear.
Participants in the study will be randomly assigned to receive either rifaximin or a placebo, which is a tablet that looks like the medication but does not contain the active ingredient. The study will observe how the medication affects various responses, such as stress levels measured by saliva tests, skin reactions, and heart rate. Additionally, the study will look at changes in gut bacteria and other health markers.
The trial is designed to be "triple-blind," meaning that neither the participants, the researchers, nor the people analyzing the results will know who is receiving the actual medication or the placebo. This helps ensure that the results are unbiased. The study will take place over a period of time, with participants taking the medication or placebo and undergoing various tests to measure their responses to stress and fear.
The research process
The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.
Who can join the trial?
7 criteria
- The participant must provide voluntary written informed consent. This means they agree to join the study after being fully informed about it.
- The participant must be able to speak and understand English or Dutch.
- The participant must be healthy with no complaints related to the intestines or psychological issues.
- The participant must have access to a freezer that can reach -18°C, which is a typical household freezer.
- Only male participants can join the study.
- The participant must be between the ages of 18 and 50 years.
- The participant's Body Mass Index (BMI) must be between 18.5 and 25 kg/m². BMI is a measure of body fat based on height and weight.
Who cannot join the trial?
3 criteria
- Participants must be healthy volunteers. This means you should not have any current medical conditions.
- Only men can participate in this study.
- Participants should not be part of a vulnerable population. This means you should not be in a group that needs special protection, like children or people with certain disabilities.
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Investigated drugs
Rifaximin is a medication used in this study to see if it can change the bacteria in the gut. The researchers want to find out if these changes can help reduce stress and fear responses in healthy men. Rifaximin works by affecting the gut microbiota, which is the community of microorganisms living in the intestines. By altering these microorganisms, the study aims to see if there is a positive impact on how the body and mind react to stress and fear.
What is already known about the treatment
Rifaximin – Rifaximin is taken orally in the form of tablets and is currently being studied for its effects on gut bacteria and how this might influence stress and fear responses in healthy men. While it is already used in medicine for other conditions, this study is exploring new potential benefits. The main focus is on how altering gut bacteria with rifaximin might help manage psychological stress. Rifaximin works by targeting bacteria in the gut, reducing their numbers and potentially affecting the gut-brain connection. It is classified as an antibiotic, specifically a rifamycin derivative.
Investigated diseases
Healthy volunteers – Healthy volunteers are individuals who do not have the disease or condition being studied. They participate in clinical trials to help researchers understand how a disease progresses or how a treatment affects the body. In studies involving healthy volunteers, researchers may focus on understanding normal biological or psychological processes. These individuals provide baseline data that can be compared to data from patients with the disease. Healthy volunteers are crucial for ensuring that new treatments are safe and effective. Their participation helps in identifying potential side effects and understanding the body's response to new interventions.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IITrial ID2024-517808-11-00Protocol codeS66407Estimated enrolment60 patientsSponsorUZ Leuven
sourced from the EU Clinical Trials Register and site verification
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