Hospital Universitario De La Princesa
Madrid, Spain
Not recruiting
A study to compare how hydrochlorothiazide tablets work in healthy volunteers
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What is this trial about?
A plain-language summary of the goals, design and what participants do
This study is being conducted to evaluate the bioequivalence of two different versions of hydrochlorothiazide. This medication is a type of diuretic, which is a substance used to help the body remove excess water and salt through urination. The study compares a test version of the tablet against a known commercial version of the same medicine.
The research involves healthy volunteers who will take a single oral dose, meaning the medicine is swallowed, while in a fasting state, which means not eating or drinking anything except water for a certain period before the test. The participants will undergo a crossover process, where they receive different treatments at different times during the study period to allow for a direct comparison between the two formulations.
The research process
The trial runs in 2 steps – from screening to follow-up. Each step says what happens and what the team monitors.
Who can join the trial?
8 criteria
- Men or women who agree to take part in the study by providing written permission after being told about the study goals, how it works, and any possible risks.
- People between the ages of 18 and 55.
- People who do not have any important physical or mental health conditions.
- People who do not have any important health problems found during a physical examination (a checkup by a doctor) or in their medical history.
- People who have normal results in blood tests, which include checks for haematology (the study of blood cells), coagulation (how well your blood clots), biochemistry (the chemical processes in your body), and serology (testing your blood for specific infections like Hepatitis B, Hepatitis C, or HIV).
- People who have normal results from a urinalysis (a test of your urine).
- People who have normal vital signs, such as blood pressure, heart rate, and temperature.
- People who have a normal electrocardiogram, which is a test that records the electrical activity of your heart.
Who cannot join the trial?
17 criteria
- People who have any physical or mental health conditions.
- People with abnormal blood test results, specifically those showing damage to the liver (an organ that processes chemicals in the body) or the kidneys (organs that filter waste from the blood). This includes high levels of certain enzymes like GOT, GPT, GGT, or bilirubin, which are substances measured in the blood to check organ health.
- People who smoke.
- People who drink alcohol every day or have experienced alcohol poisoning (a dangerous reaction to too much alcohol) in the last week.
- People who have donated blood within the last month.
- Pregnant women or women who are breastfeeding.
- Women of child-bearing age who do not agree to use a highly effective contraceptive method (a way to prevent pregnancy) or agree to avoid sex during the study.
- People with an allergy or sensitivity to wheat starch.
- People with anuria, which is a condition where the kidneys do not produce any urine.
- People who have taken experimental drugs in another study within the last 3 months.
- People who are unable to follow instructions or cooperate with the study requirements.
- People with a history of difficulty swallowing.
- People with rare inherited digestive problems, such as difficulty processing certain sugars like galactose, lactose, or glucose.
- People who have taken prescribed medicine in the last 15 days or any type of medication in the 48 hours before the study medication is given, although women are allowed to use contraceptives (birth control) if they have been using them for at least 4 weeks.
- People whose Body Mass Index (BMI), which is a calculation using weight and height to see if a person is a healthy weight, is not between 18.5 and 30.0.
- People with a history of allergic reactions to any medication.
- People who test positive for illegal drugs, such as cannabis, opiates, cocaine, or amphetamines.
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Investigated drugs
Hydrochlorothiazide is a medication that acts as a diuretic, often called a "water pill." It works by helping the body get rid of extra salt and water through urine, which helps manage fluid levels.
What is already known about the treatment
Hydrochlorothiazide - This medication is taken as a tablet by mouth and is widely used in medicine to treat high blood pressure and swelling caused by excess fluid in the body. It belongs to a group of drugs called diuretics, often referred to as "water pills," which help the body get rid of extra salt and water. At a molecular level, it works by helping the kidneys release more sodium into your urine, which naturally pulls water out of your system and reduces the pressure in your blood vessels.
Investigated diseases
No diseases are mentioned in the provided source data.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase ITrial ID2023-505692-72-00Protocol codeN-HID-23-279Estimated enrolment30 patientsSponsorLaboratorios Normon S.A.
sourced from the EU Clinical Trials Register and site verification
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