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Study on Naproxen Sodium and Paracetamol for Patients with Knee Osteoarthritis

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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 naproxen sodium, which is found in a product named Nalgesin Forte. The study is specifically looking at its impact on people with knee osteoarthritis, a condition that causes pain and stiffness in the knee joint. The trial will compare the effects of naproxen sodium to a placebo, which is a substance with no active medication, to see how it affects certain substances in the knee joint fluid and overall knee health.

The purpose of the study is to understand how a two-week treatment with naproxen sodium influences the levels of a protein called Interleukin-6 (IL-6) in the fluid of the knee joint. IL-6 is involved in inflammation, which is a part of the body's response to injury or disease. Participants in the study will be randomly assigned to receive either naproxen sodium or a placebo. The study will also look at other proteins related to inflammation and assess changes in pain and knee function.

Throughout the study, participants will take the medication orally in the form of film-coated tablets. The trial will last for two weeks, during which the effects of the treatment on knee pain, symptoms, and daily activities will be monitored. The study aims to provide insights into how naproxen sodium can help manage symptoms of knee osteoarthritis and improve the quality of life for those affected by this condition.

The research process

The trial runs in 5 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, your eligibility for the trial will be confirmed. This includes checking your age, diagnosis of knee osteoarthritis, and pain levels.

    An ultrasound examination of your knee will be performed to ensure there is enough synovial fluid for analysis. You will also be asked to sign consent forms for participation and data collection.

  2. Step 2

    Randomization and medication

    You will be randomly assigned to one of the study groups. This means you will either receive the active medication, naproxen sodium (Nalgesin Forte, 550 mg), or a placebo (a tablet that looks like the medication but has no active ingredients).

    The medication is taken orally as a film-coated tablet. You will take one tablet twice a day for a period of 14 days.

  3. Step 3

    Treatment period

    During the 14-day treatment period, you will continue taking the assigned tablets as instructed. It is important to adhere to the dosage and frequency to ensure the trial's accuracy.

    You may be asked to keep a diary of your symptoms and any side effects you experience during this time.

  4. Step 4

    Follow-up visit

    After completing the 14-day treatment, you will return for a follow-up visit. At this visit, another ultrasound examination will be conducted, and synovial fluid will be collected from your knee.

    The collected fluid will be analyzed to measure the concentration of certain substances, such as Interleukin-6 (IL-6), which is related to inflammation.

  5. Step 5

    Final assessment

    The final assessment will involve evaluating changes in your symptoms and overall knee function. This may include completing questionnaires about your pain levels and quality of life.

    The results from your assessments and fluid analysis will contribute to understanding the effects of the treatment.

Who can join the trial?

8 criteria

  • Patients must be female or male and at least 40 years old.
  • Patients must have been diagnosed with primary osteoarthritis of the knee, with a severity of grade III or IV according to the Kellgren-Lawrence classification (a system used to classify the severity of osteoarthritis).
  • The average pain level in the knee joint being studied must be 6 or less on a numeric rating scale (NRS) in the last 24 hours.
  • An ultrasound examination of the knee must show enough synovial fluid (a lubricating fluid in the joint) to withdraw at least 1ml.
  • Patients must have been given information about the trial and have voluntarily signed the informed consent form.
  • Patients must have signed consent for the collection, analysis, and processing of personal data for the trial's statistical analysis and final report.
  • Patients must be able to follow the trial protocol according to the investigator's judgment.
  • A successful arthrocentesis (a procedure to remove fluid from the joint) of the knee must be performed during Visit 2, obtaining at least 1ml of synovial fluid without visible blood.

Who cannot join the trial?

8 criteria

  • Patients who have any other joint diseases besides knee osteoarthritis.
  • Patients who are currently taking any medication that might interfere with the study treatment.
  • Patients with a history of allergic reactions to naproxen sodium or similar medications.
  • Patients with severe liver or kidney problems.
  • Patients with a history of stomach ulcers or bleeding.
  • Patients who are pregnant or breastfeeding.
  • Patients who have participated in another clinical trial within the last 30 days.
  • Patients with any condition that the study doctors believe would make it unsafe for them to participate.
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Investigated drugs

Naproxen Sodium (Nalgesin® Forte) is a medication used in this clinical trial to help manage pain and inflammation in patients with knee osteoarthritis. It works by reducing the levels of certain substances in the body that cause inflammation and pain. In this study, researchers are looking at how this medication affects the levels of a specific protein called Interleukin-6 in the joint fluid of the knee, as well as its overall impact on the symptoms of osteoarthritis after two weeks of treatment.

What is already known about the treatment

Naproxen Sodium (Nalgesin® Forte) – This medication is taken orally in the form of tablets and is used to relieve pain and inflammation. It is currently being studied in clinical trials for its effects on knee osteoarthritis, a condition that causes joint pain and stiffness. Naproxen works by reducing the levels of certain chemicals in the body that cause inflammation and pain, specifically targeting a substance called Interleukin-6 (IL-6) in the joint fluid. It belongs to a group of drugs known as nonsteroidal anti-inflammatory drugs (NSAIDs).

Investigated diseases

Knee Osteoarthritis – Knee osteoarthritis is a degenerative joint disease characterized by the breakdown of cartilage in the knee joint. As the cartilage wears away, bones begin to rub against each other, leading to pain, swelling, and reduced joint mobility. Over time, the joint may become stiff and lose its normal shape, and bone spurs may develop. The progression of the disease can lead to increased discomfort and difficulty in performing daily activities. Symptoms often worsen with activity and improve with rest. The condition is more common in older adults and can be influenced by factors such as weight, genetics, and previous joint injuries.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2023-505875-56-00Protocol codeKCT23/2022-ZOOM-INEstimated enrolment38 patientsSponsorKRKA tovarna zdravil d.d. Novo mesto

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