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Study on the Effects of Promethazine on Coordination in Healthy Volunteers During Altered Gravity Conditions

Registered drug
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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 the medication promethazine on healthy individuals. Promethazine is a medication commonly used to treat allergies, nausea, and motion sickness. The study will also explore how changes in gravity, such as those experienced during parabolic flight, affect the ability to coordinate movements using both hands, known as bimanual coordination.

The purpose of the study is to understand how different doses of promethazine and varying gravity levels impact the performance of tasks that require the use of both hands. Participants will be exposed to different gravity levels and will perform tasks that test their coordination. The study will observe how well participants can perform these tasks under the influence of the medication and during rapid changes in gravity.

Participants in the study will include healthy volunteers who will be given either promethazine or a placebo. The study will monitor their performance on coordination tasks to see if the medication or changes in gravity affect their ability to perform these tasks. The findings from this study could provide valuable insights into how medications like promethazine and altered gravity conditions influence human motor skills.

The research process

The trial runs in 6 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial visit

    Upon joining the study, you will attend an initial visit. During this visit, you will receive detailed information about the study and what to expect. You will also have the opportunity to ask any questions you may have.

    You will be required to provide written consent to participate in the study. This consent confirms that you understand the study and agree to take part.

  2. Step 2

    Medical examination

    A medical examination will be conducted to ensure you meet the health criteria for participation. This examination is similar to a standard aviation medical examination for private pilot aptitude.

    The examination will assess your overall health and confirm that you are a healthy volunteer, aged between 18 and 55, with a body mass index (BMI) of less than 30.

  3. Step 3

    Medication administration

    You will be administered PHENERGAN 25 mg, which is a coated tablet containing promethazine hydrochloride. This medication will be taken orally.

    The dosage and frequency of the medication will be explained to you during the study. It is important to follow the instructions provided by the study team.

  4. Step 4

    Bimanual coordination tasks

    You will participate in tasks that assess bimanual coordination. These tasks are designed to evaluate how well you can use both hands together in various activities.

    The tasks will be conducted under different gravity conditions to study the effects of altered gravity on coordination.

  5. Step 5

    Follow-up visits

    Throughout the study, you will attend follow-up visits. These visits are scheduled to monitor your health and the effects of the medication.

    During these visits, you will have the opportunity to discuss any concerns or side effects you may experience.

  6. Step 6

    Study completion

    At the end of the study, you will have a final visit. This visit will include a final assessment of your health and a review of your participation in the study.

    You will receive information about the study's findings and any next steps, if applicable.

Who can join the trial?

8 criteria

  • Participants must be healthy volunteers, meaning they should not have any significant medical conditions.
  • Participants can be men or women.
  • Participants must be aged between 18 and 55 years old.
  • Participants should have a body mass index (BMI) of less than 30. BMI is a measure of body fat based on height and weight.
  • Participants must be affiliated with a Social Security system. If they are not residents of France, they should have a European Health Insurance Card (EHIC) or a Global Health Insurance Card (GHIC).
  • Participants must have agreed to take part in the study and have given their written consent.
  • Participants must have passed a medical examination similar to the one required for private pilots. This is known as a JAR FCL3 Class 2 medical examination.
  • Participants must be right-hand dominant. This means they primarily use their right hand for tasks. This is measured by a score of +60 or higher on the Edinburgh Handedness Questionnaire, which ranges from -100 to +100.

Who cannot join the trial?

4 criteria

  • Participants must be healthy volunteers. This means you should not have any medical conditions.
  • Participants must be within a specific age range, which is not specified here.
  • Both male and female participants are eligible.
  • Participants should not be part of a vulnerable population. This generally refers to groups who may need special protection, such as children, pregnant women, or those unable to give consent.
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Investigated drugs

Promethazine is a medication that is often used to help with allergies, nausea, and motion sickness. In this clinical trial, it is being studied to see how it affects people's ability to coordinate movements with both hands when they are in different gravity conditions, like those experienced during a parabolic flight. The researchers want to understand if taking promethazine changes how well people can perform tasks that require using both hands together when the gravity around them changes quickly.

What is already known about the treatment

Promethazine – Promethazine is typically administered orally in the form of tablets or liquid, and it can also be given as an injection. It is currently well-established in medical literature as an antihistamine used to treat allergies, nausea, and motion sickness. In this clinical trial, it is being studied for its effects on bimanual coordination during altered gravity conditions. At the molecular level, promethazine works by blocking histamine receptors in the brain, which helps reduce symptoms like nausea and dizziness. It is classified pharmacologically as a first-generation antihistamine.

Investigated diseases

Healthy volunteers – This term refers to individuals who do not have any known medical conditions or diseases. They are often used in clinical trials to provide baseline data for comparison with individuals who have specific health conditions. Healthy volunteers help researchers understand how a drug or treatment affects the human body without the interference of existing health issues. Their participation is crucial in determining the safety and efficacy of new treatments. The progression of their health status is typically stable, as they do not have underlying diseases. They serve as a control group to ensure that any changes observed in the study are due to the treatment being tested.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-504256-10-00Protocol codeBMC in AGEstimated enrolment16 patientsSponsorNovespace

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