If your fingers hurt from arthritis and regular pain medicine does not seem to work well, there may be a new treatment worth knowing about. Scientists are testing a special patch made from chili peppers to see if it helps a certain type of finger pain.
This article looks at a new study called CADOR. The study tests whether a patch with a very high dose of a chili pepper ingredient called capsaicin can reduce pain in people with finger arthritis who have nerve type pain.
Here are three key points:
- The patch contains a compound from chili peppers that is applied to the skin for just 30 minutes.
- The study is testing people with finger arthritis who have pain that feels like nerve pain.
- Regular pain medicine like anti inflammatory drugs does not work very well for this type of pain.
Key Findings at a Glance
- According to this study, capsaicin 8% patches are being tested for finger arthritis pain that feels like nerve pain.
- Research shows that a single 30 minute application is being compared to a very low dose control patch.
- Studies indicate that patients with neuropathic-like pain often do not respond well to standard pain medicines.
- The trial involves 120 patients and measures pain levels over 60 days after one treatment.
- According to the study design, patients who still have pain after 60 days can receive an open label high dose capsaicin patch.
In This Article
What Is This Study About?
The CADOR study is looking at a new way to help people who have painful fingers from arthritis. The name stands for Capsaicin in neuropathic-like pain in Digital Osteoarthritis: a Randomised trial.
Let us look closer at what that means.
Many people with finger arthritis have a type of pain that feels different from regular joint pain. It can feel like burning, tingling, or shooting pain. This is called neuropathic-like pain because it feels like nerve pain.
You may be wondering why this matters.
According to this study, regular pain medicines like anti inflammatory drugs do not work very well for this nerve type pain in finger arthritis. That is why scientists are looking for new treatments.
What Is Capsaicin?
Capsaicin is the ingredient in chili peppers that makes them feel hot and spicy. When you eat a hot pepper, capsaicin is what makes your mouth burn.
Here is where it gets interesting.
Scientists discovered that capsaicin can also help with pain. When it is put on the skin in a very high dose, it can numb the nerves for a while. This can reduce pain for weeks or even months after just one treatment.
Research shows that capsaicin is already approved in many countries for treating nerve pain in other parts of the body. But it has never been tested in a large randomized study for finger arthritis pain.
How Is Capsaicin Different from Other Pain Medicines?
Most pain medicines need to be taken every day. They go into your whole body through your stomach or bloodstream.
Capsaicin is different. It is applied directly to the painful area as a patch on your skin. The patch stays on for just 30 minutes. Then it is removed. But the pain relief can last for weeks.
This is because capsaicin works directly on the nerves in the skin. It does not go through your whole body.
Who Is Included in This Study?
The CADOR study is recruiting 120 people. All of them must meet certain requirements to join.
According to the study design, patients must have:
- Finger arthritis that meets official medical criteria set by the American College of Rheumatology.
- X-rays showing at least moderate arthritis damage in the fingers.
- Pain that feels like nerve pain, with a score of at least 4 out of 10 on a special questionnaire called DN4.
- Pain intensity of at least 40 out of 100 on a pain scale.
The study is being done at multiple medical centers in France. It is a phase 3 clinical trial, which means it is one of the final steps before a treatment can be approved for regular use.
How Does the Treatment Work?
At the start of the study, all 120 patients are divided randomly into two groups. Neither the patient nor the doctor knows which group they are in. This is called a double blind study.
What Happens on Day 0?
On the first day of the study, patients receive one of two treatments:
- The experimental group gets a patch with 8% capsaicin. This is a very high dose.
- The control group gets a patch with only 0.04% capsaicin. This is a very low dose that acts as a comparison.
The patch is applied to the painful fingers for exactly 30 minutes. Then it is removed. That is the only treatment for the first 60 days.
What Happens on Day 60?
After 60 days, researchers measure how much pain patients have. If patients still have significant pain (40 or more out of 100), they can choose to receive another treatment.
This time, everyone who wants it gets the high dose 8% capsaicin patch. This part is not blinded, which means both the patient and doctor know what treatment is being given.
What Happens on Day 120?
At 120 days, researchers check the pain levels again. They want to see if two applications of the patch work better than one.
What Are They Measuring?
The main thing researchers want to know is whether the capsaicin patch reduces pain.
Primary Outcome
The primary outcome is pain intensity in the fingers over the past 48 hours at Day 60. This is measured with a Visual Analogue Scale, or VAS.
Studies indicate that this scale is a standard way to measure pain in medical research.
Secondary Outcomes
Researchers are also looking at other important things:
- How well patients can use their hands in daily activities.
- Quality of life, which means how the pain affects their happiness and daily living.
- Anxiety and depression levels.
- How much patients feel they have improved overall.
- How much pain medicine or anti inflammatory medicine they need to use.
- Any side effects or safety problems from the capsaicin patch.
All of these measurements help researchers understand if the treatment truly helps people feel better and live better.
| Time Point | What Happens |
|---|---|
| Day 0 | Patients receive either 8% capsaicin patch or 0.04% capsaicin patch for 30 minutes |
| Day 60 | Researchers measure pain levels and other outcomes (primary endpoint) |
| Day 60 (if pain remains) | Patients can choose to receive open label 8% capsaicin patch |
| Day 120 | Researchers measure outcomes again after second treatment |
Frequently Asked Questions
Is this treatment available right now?
No, not yet for finger arthritis. According to this study, the CADOR trial is still ongoing. Researchers are testing whether the capsaicin patch works for this specific type of pain. Capsaicin patches are already approved for other types of nerve pain in some countries, but not specifically for finger arthritis pain.
Does the patch hurt when it is applied?
The abstract does not give details about how the patch feels during application. Capsaicin can cause a burning or stinging feeling on the skin. This is part of how it works. The study is also measuring safety, which will include information about side effects.
How long does the pain relief last?
According to the study design, researchers are measuring pain at 60 days after a single 30 minute application. This suggests they expect the effect to last at least two months. The study will show exactly how long the relief lasts.
Is this only for finger pain or can it help thumb arthritis too?
The study focuses on digital osteoarthritis, which means arthritis in the fingers. The abstract does not specifically mention the thumb. However, the thumb is technically a finger, and thumb arthritis often causes similar neuropathic-like pain. Future research may clarify whether the treatment works for thumb arthritis as well.
About This Site
This website is dedicated to making medical science easier to understand for people dealing with thumb pain and rhizarthrosis. We carefully read published scientific articles and translate them into simple language. Every article on this site is based on real medical research, not opinions or advertisements. We invite you to explore more content to learn about your condition and the latest treatments being studied.
What Does This Mean for You?
If you have finger arthritis with nerve type pain, this study offers hope. Research shows that scientists are actively looking for better ways to manage pain that does not respond well to regular medicines.
The CADOR study will help us understand whether a capsaicin patch can provide long lasting relief after just one short treatment. The results are not available yet, but the study design is strong and follows strict scientific standards.
If your pain feels like burning, tingling, or shooting sensations, and regular pain medicine does not help much, talk to your doctor. Ask if this type of treatment might be an option for you in the future.
Remember that new treatments take time to be fully tested and approved. But studies like this are important steps forward.
Important Information
This article is for educational purposes only. It is not medical advice. Always talk to your doctor or healthcare provider before starting, stopping, or changing any treatment. Your doctor knows your specific situation and can give you personalized advice. The information here is based on a study protocol, which means the research is planned but results are not yet available.
Article Source
Fan, A., Lambert, C., Sellam, J., Chapurlat, R., Marotte, H., Pereira, B., Thomas, T., Tournadre, A., Soubrier, M., & Mathieu, S. (2025). CADOR (Capsaicin in neuropathic-like pain in digital osteoarthritis) study protocol: a multicentre randomised parallel-group trial. BMJ Open.
https://doi.org/10.1136/bmjopen-2024-093409
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