Diclofenac Gel for Osteoarthritis

Overseen By Maya Porter

Age: 18+

Sex: Any

Trial Phase: Academic

Sponsor: University of California, Davis

Must not be taking: Blood thinners, NSAIDs

Disqualifiers: Inflammatory arthritis, Knee replacement, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 2

Duration: 8 weeks

220 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial explores how diclofenac gel, a topical anti-inflammatory medication, can alleviate knee pain from osteoarthritis, a condition where the joint wears down. Researchers aim to identify patient characteristics that lead to better outcomes with this treatment. Participants will apply the gel to their knee daily for eight weeks and report their pain levels through questionnaires. This trial may suit those who have experienced knee pain at least 15 days a month and have been diagnosed with knee osteoarthritis via X-ray in the past two years. As an unphased trial, it offers a unique opportunity to contribute to understanding how diclofenac gel can best assist those with knee osteoarthritis.

Will I have to stop taking my current medications?

The trial requires that you stop using topical or oral NSAIDs more than 3 days per week. If you're taking blood thinners, you may need to stop, except for aspirin 81 mg daily, which is allowed.

What prior data suggests that topical diclofenac gel is safe for individuals with knee osteoarthritis?

Research has shown that diclofenac gel, when applied to the skin, is generally safe and well-tolerated. It effectively reduces knee pain from osteoarthritis and is usually gentler on the body than oral medications. For instance, one study found that the gel relieved pain with fewer side effects than oral medications. Another study confirmed its effectiveness and safety for knee pain relief over a three-week period. Although limited information exists on its long-term use in everyday life, clinical studies consistently report that diclofenac gel is a safe option for managing knee pain from osteoarthritis. ^{1 2 3 4 5}

Why are researchers excited about this trial?

Unlike the standard oral medications and injections typically used for osteoarthritis, Diclofenac Gel offers a topical treatment option. This gel is applied directly to the affected knee, which can help reduce systemic side effects often associated with oral NSAIDs (non-steroidal anti-inflammatory drugs) like stomach issues or cardiovascular risks. Researchers are excited about this treatment because it allows for targeted pain relief right where it's needed, potentially leading to improved patient comfort and adherence.

What evidence suggests that topical diclofenac gel is effective for osteoarthritis?

Research has shown that diclofenac gel, when applied to the skin, helps relieve knee osteoarthritis pain. Studies have found that this gel significantly reduces pain and improves movement compared to a placebo, which contains no active medicine. One study found that using diclofenac gel for three weeks provided safe relief from osteoarthritis symptoms. Another report showed that it noticeably reduced pain over 8 to 12 weeks. These findings suggest that diclofenac gel could be a helpful treatment for knee osteoarthritis. Participants in this trial will apply topical diclofenac gel 1% to the index knee for 8 weeks. ^{1 2 4 5 6}

Who Is on the Research Team?

Michelle Dossett, MD, PhD, MPH

Principal Investigator

University of California, Davis

Are You a Good Fit for This Trial?

This trial is for individuals with knee osteoarthritis who are willing to apply diclofenac gel on their knee and can attend two study visits. Participants will also need to answer biweekly questions about their knee pain and treatment usage.

Inclusion Criteria

English-speaking

I experience knee pain for at least 15 days each month.

I am 50 years old or older.

Exclusion Criteria

I use NSAID medications more than three times a week.

Inability to receive text messages or email

I cannot take NSAIDs due to a serious health condition or allergy.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Initial Study Visit

Participants attend the first study visit to complete baseline questionnaires, have blood drawn, and receive diclofenac gel

1 day

1 visit (in-person)

Treatment

Participants apply topical diclofenac to their knee for 8 weeks and complete biweekly questions about knee pain and diclofenac use

8 weeks

Biweekly virtual check-ins

Follow-up

Participants attend a follow-up visit to complete final questionnaires and assess outcomes

1 day

1 visit (in-person)

What Are the Treatments Tested in This Trial?

Interventions

• Topical Diclofenac gel

Trial Overview The study aims to determine how patient characteristics, physiological responses during clinic visits, and the nature of these visits influence the effectiveness of topical diclofenac gel in managing knee OA pain.

How Is the Trial Designed?

Group I: Diclofenac Experimental Treatment 1 Intervention

All study participants receiving topical diclofenac gel 1%. Participants will be instructed to apply 4 grams of the gel to the index knee at least once per day, and up to 4 times per day, for 8 weeks.

Who Is Running the Clinical Trial?

University of California, Davis

Lead Sponsor

Trials

958

Recruited

4,816,000+

Beth Israel Deaconess Medical Center

Collaborator

Trials

872

Recruited

12,930,000+

National Institute on Aging (NIA)

Collaborator

Trials

1,841

Recruited

28,150,000+

Citations

1. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/21174485/

Safety and efficacy of topical diclofenac sodium gel for ... Conclusions: DSG was effective and generally well tolerated in adults regardless of age. These data support the topical application of DSG for relief of OA knee ...

2. bmcmusculoskeletdisord.biomedcentral.com bmcmusculoskeletdisord.biomedcentral.com/articles/10.1186/s12891-025-08465-7

Efficacy and safety of different topical diclofenac formulations ... Topical diclofenac formulations (gel, solution, patch) significantly improve pain and function in knee osteoarthritis compared to placebo.

3. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC7211216/

Topical Diclofenac, an Efficacious Treatment for Osteoarthritis Statistically significant improvements in pain relief were found for diclofenac solution [standardized mean difference (SMD) vs. placebo − 0.29; ...

4. jrheum.org jrheum.org/content/32/12/2384

Efficacy of topical diclofenac diethylamine gel in ... CONCLUSION: Diclofenac gel was effective and safe for relief of symptoms of OA of the knee over 3 weeks of dosing. We recommend. Diclofenac ...

5. sciencedirect.com sciencedirect.com/science/article/pii/S0049017215002851

Efficacy and safety of topical NSAIDs in the management ... The most data available was for topical diclofenac in OA, where the number needed to treat (NNT) for at least 50% pain relief over 8–12 weeks compared with ...

6. link.springer.com link.springer.com/article/10.1007/s40122-025-00723-9

Evaluating the Real-World Use of Topical Diclofenac ... While clinical studies show that DSG1% is safe and well-tolerated, long-term safety and tolerability in real-world settings are limited. This ...