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Bioavailability of 50 mg dimenhydrinate granules taken with or without water versus reference formulations for nausea and vomiting in healthy volunteers

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

The study focuses on a medication used to prevent and treat nausea and vomiting, especially the type caused by motion (kinetosis). The test product contains the active ingredient dimenhydrinate in a coated granule form, while two established medicines, Vomex A (a liquid solution) and Biodramina (tablet), serve as reference standards.

The purpose is to determine whether the test product has similar bioavailability—the amount of drug that reaches the bloodstream—as the reference medicines. Healthy volunteers receive a single dose of each product in a random order, with at least a week between doses. In some periods the test granules are taken with a small amount of water, in others without water, and all doses are given while the participants have not eaten (fasting). This design allows each participant to act as their own comparison, helping to show if the new form works the same as the existing treatments.

The research process

The trial runs in 9 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Randomization and assignment to a dosing sequence

    After enrollment, you will be randomly placed into one of four possible sequences. each sequence determines the order in which you will receive the four study medications during the trial.

  2. Step 2

    First dosing period

    You will arrive at the study site after at least ten hours of fasting (no food or drink except water).

    The first medication assigned by your sequence will be given as a single dose. the dose is 50 mg of dimenhydrinate, provided in the form specified for that period:

    - if the medication is the test preparation without water, you will swallow the coated granules directly with no water.

    - if the medication is the test preparation with water, you will swallow the coated granules together with 200 mL of water.

    - if the medication is the reference product Vomex A, you will ingest the oral solution containing 50 mg dimenhydrinate.

    - if the medication is the reference product Biodramina, you will ingest one tablet containing 50 mg dimenhydrinate.

    After taking the medication, you will remain at the site for a series of blood samples that are taken over several hours to measure how the drug is absorbed.

  3. Step 3

    Washout period before the next dose

    At least seven days must pass before the next dosing period. during this time you may resume normal eating and drinking, but you must not take any other medication containing dimenhydrinate.

  4. Step 4

    Second dosing period

    The same procedures as in step 2 are repeated, using the second medication assigned by your sequence. you will again fast for at least ten hours, receive a single dose of 50 mg dimenhydrinate in the specified form, and stay for blood sampling.

  5. Step 5

    Washout period before the third dose

    Another minimum seven‑day interval is required before the third dosing period.

  6. Step 6

    Third dosing period

    You will repeat the fasting, dosing, and observation procedures with the third medication assigned by your sequence.

  7. Step 7

    Washout period before the fourth dose

    A final minimum seven‑day interval separates the third and fourth dosing periods.

  8. Step 8

    Fourth dosing period

    You will complete the trial by following the same steps—fasting, taking the last assigned 50 mg dimenhydrinate dose, and remaining for blood sampling.

  9. Step 9

    Final follow‑up

    After the last blood sample, you will be asked to report any adverse effects that occurred during the study. no further medication will be taken.

Who can join the trial?

8 criteria

  • You must be a man or a woman who wants to join the study.
  • You need to be between 18 and 55 years old on the day you sign the consent form.
  • If you are a woman who cannot become pregnant, you may join. This includes women who have naturally stopped having periods for at least 12 months (menopause), women who had both ovaries removed at least 6 weeks ago (called bilateral oophorectomy), or women who have had a permanent fallopian‑tube surgery (tubal ligation).
  • If you are a woman who could become pregnant (reproductive potential), you must use a reliable birth‑control method (or agree to start one) from the time you sign the consent until the study ends.
  • You must be in good physical and mental health, as shown by a medical check‑up and standard lab tests.
  • You must be a non‑smoker or have stopped smoking at least 6 months ago, with a total smoking history of no more than 5 pack‑year equivalents (one pack‑year means smoking one pack per day for one year). You also must not use any other nicotine products, and this will be confirmed with a urine test.
  • Your Body Mass Index (BMI) – a number that compares your weight to your height – must be between 18.5 and 30.0, inclusive.
  • You must sign a written informed consent form agreeing to take part in the trial.

Who cannot join the trial?

30 criteria

  • Participation in another clinical trial at the same time or within the past 90 days.
  • Being enrolled in this study more than once.
  • Giving blood or losing more than 500 mL of blood (including plasma donation) within the past 90 days.
  • Having a history of drug or illegal drug use (marijuana within 6 months, cocaine, amphetamines, etc., within 1 year).
  • Drinking too much alcohol (more than 2 drinks per day or 10 drinks per week, or a history of alcoholism).
  • Consuming large amounts of caffeine‑containing drinks or foods (more than about 500 mg of caffeine per day, roughly 5 cups of coffee).
  • Having a positive drug test.
  • Having a positive alcohol test.
  • Being pregnant, possibly pregnant, or breastfeeding.
  • Having any significant allergy, such as asthma or other allergic diseases.
  • Being allergic to dimenhydrinate or any of its ingredients.
  • Having any important medical condition, such as heart, kidney, liver, lung, metabolic, hormone, blood, digestive, nerve, or mental health problems.
  • Being sick with a significant illness within the last 4 weeks.
  • Having had major stomach or intestinal surgery (except a simple appendix removal).
  • Having a chronic disease that could affect how the drug is absorbed, spread, broken down, or removed from the body.
  • Having difficulty swallowing.
  • Testing positive for HIV, hepatitis B, or hepatitis C infections.
  • Receiving long‑acting injectable medicines (half‑life longer than 1 week) within the last 6 months.
  • Taking medicines that affect enzymes, are toxic to organs, or stay in the body a long time, within the last 4 weeks.
  • Taking any regular medication (including over‑the‑counter drugs, antacids, or herbal products like St. John’s wort or kava) within the last 2 weeks.
  • Receiving a vaccination within the last 14 days.
  • Taking drugs that can change major body systems (such as barbiturates, phenothiazines, cimetidine, omeprazole) within the last 60 days.
  • Having a resting blood pressure outside 100‑140 mm Hg (systolic) or 60‑90 mm Hg (diastolic).
  • Having a resting pulse rate outside 50‑90 beats per minute.
  • Having an axillary (under‑arm) temperature outside 35.5‑37.1 °C.
  • Having a significant abnormality on a resting 12‑lead ECG (heart rhythm test).
  • Having laboratory test results that are outside the normal range and are clinically important.
  • Following a special diet (for example, vegetarian) that could affect the study.
  • Having mouth piercings, braces, or dentures.
  • Being judged unlikely to follow the study rules, to understand the information, or to give reliable consent, or being in a precarious financial or legal situation (such as custody).
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Investigated drugs

  • Dimenhydrinate

    is the medication being tested in this study. It is a drug that helps prevent nausea, vomiting, and dizziness caused by motion sickness. In the trial, it is given as coated granules that the participants take by mouth, either with water or without water, to see how well it works compared to the standard products.

  • Vomex A

    is one of the reference medicines used for comparison. It is an oral solution that contains dimenhydrinate, the same active ingredient as the test product. Participants take this liquid form of the drug to provide a standard against which the new granule formulation can be measured.

  • Biodramina

    is the second reference medicine in the study. It comes as tablets that also contain dimenhydrinate. This tablet version serves as another standard comparison, helping researchers understand how the new granule form performs relative to an existing tablet product.

What is already known about the treatment

  • Vomex A 50 mg Lösung zum Einnehmen im Beutel

    This product is an oral solution that is mixed with water and drunk as a single dose. Dimenhydrinate, the active ingredient, is an approved over‑the‑counter medicine used to prevent and treat nausea and vomiting, especially motion sickness. It works by blocking the action of histamine in the brain, which helps stop the feeling of nausea. It is classified as an antihistamine and anti‑emetic.

  • Biodramina 50 mg Comprimidos

    These are tablets that are swallowed with water in a single dose. Dimenhydrinate in this form is also an approved over‑the‑counter drug for preventing and relieving nausea and vomiting, particularly from motion. The drug reduces nausea by preventing histamine from acting in the brain. It belongs to the antihistamine and anti‑emetic class.

  • DIMENHYDRINATE

    This test product consists of coated granules taken orally, either with water or directly without water. Dimenhydrinate is a well‑known medication that has been approved for use in preventing and treating nausea and vomiting, especially motion‑induced symptoms. It reduces nausea by blocking histamine receptors in the brain that trigger the vomiting reflex. It is categorized as an antihistamine and anti‑emetic.

Investigated diseases

Motion sickness - Motion sickness occurs when the brain receives mismatched signals about movement from the inner ear, eyes, and other sensors. It usually starts with a sense of unease, quickly leading to nausea and may progress to vomiting if the motion continues. Symptoms often appear within minutes of traveling by car, boat, plane, or during virtual reality experiences. The intensity can increase with longer exposure or stronger sensory conflict. Some individuals develop anticipatory symptoms before travel. The condition typically subsides once the motion stops.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase ITrial ID2022-502420-51-00Protocol codeCHE21003Estimated enrolment14 patientsSponsorCCDRD Cooperative Clinical Drug Research and Development AG

sourced from the EU Clinical Trials Register and site verification

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