Evidence based

How Diclofenac Gel Can Relieve Your Pain

Last updated: 
October 5, 2019
Natalie Pertsovsky
Researcher and author
Dr. Juliana Bruner, DPT
Researcher and author, Physical Therapist

Physical therapy and over-the-counter NSAIDs (for example, Advil) are the best first-line treatments for pain in your back, joints, and knees. However, if your pain persists, then you may want to try stronger prescription medications while you continue with a physical therapy program.

One option worth considering is diclofenac gel. This article will explain the benefits and risks of diclofenac gel and help you determine if it can help with your pain.

What Is Diclofenac Gel and How Exactly Does It Work?

Like ibuprofen and aspirin, diclofenac gel is a nonsteroidal anti-inflammatory drug (NSAID) that works by inhibiting the inflammatory actions of the COX-2 enzyme (1).

Diclofenac gel can be applied directly to the skin to target specific areas of discomfort. The most common brand names are Voltaren and Pennsaid. Voltaren is a gel, while Pennsaid is a liquid.

Another topical diclofenac, Solaraze, has been shown to improve actinic keratosis. This condition is caused by years of sun exposure and manifests as rough, scaly patches on the body.


Diclofenac gel works by inhibiting enzymes that produce inflammatory agents called prostaglandins.

Why Try Diclofenac Gel?

Diclofenac gel can treat pain from a range of musculoskeletal conditions and has a favorable side effect profile relative to oral NSAID medications.

Reduced Incidence of Side Effects

Topical NSAIDs, including gels, liquids and patches are as effective as oral NSAIDs, but generally carry fewer risks and side effects (2).

Oral NSAIDs, such as ibuprofen, naproxen and aspirin, alleviate pain and swelling, but can increase blood pressure and exacerbate heart conditions. In recent years, the FDA has issued stronger warnings about the increased risk of heart attack and stroke due to oral NSAIDs (3). Additionally, these medications often cause stomach pain.

In contrast, research indicates that topical NSAIDs provide similar pain relief to oral NSAIDs, with less risk (4).

A 2017 study investigated the use of topical and oral NSAIDs in the treatment of rheumatoid arthritis, and found that topical NSAID use resulted in fewer instances of cardiovascular complications (5).

Another study compared oral and topical diclofenac solutions, and found that topical treatments resulted in fewer gastrointestinal (GI) and heart-related adverse events (2).

Back Pain

Research shows that diclofenac gel effectively relieves low back pain, especially when combined with other therapies such as muscle relaxers and ultrasound therapy (6). Compared to other NSAID options, diclofenac results in fewer side effects when used to treat low back pain, even when comparing oral diclofenac to oral forms of other NSAIDs (which corrects for the inherent advantages of topicals over orals) (7).

Diclofenac is particularly useful in cases of acute musculoskeletal pain, and recent findings also indicate that diclofenac can help in more chronic cases of nerve-related pain as well as in cases of muscle strain (6, 8, 9, 10).


Diclofenac gel is also useful for treating arthritis pain, a disease that affects over 50 million Americans (11, 12).

Most people with arthritis have osteoarthritis, which gradually wears down the cartilage within joints (13). Researchers have found that topical diclofenac significantly reduces pain and stiffness while improving physical function in cases of osteoarthritis [14]. Treatment with diclofenac also carries few adverse effects even in cases of long-term use by elderly patients, regardless of the severity of osteoarthritis (15, 16).

Knee Pain

Research supports the use of topical diclofenac in treating knee pain.

Topical diclofenac solutions have proven effective for site-specific treatment for osteoarthritis knee pain (17). Treated patients displayed improved physical functioning and reduced stiffness, while only experiencing minor skin irritation at the application site as a side effect.

Additional clinical trials have revealed comparable findings.

One randomized trial demonstrated significant improvement of osteoarthritis pain with 2% diclofenac gel (18). And in Germany, patients used topical diclofenac diethylamine gel regularly for three weeks with positive results (19).

A separate study tested the strength of diclofenac hydroxyethylpyrrolidine (DHEP) plasters. The DHEP patches substantially diminished patients’ osteoarthritic knee pain (20).

Other Uses of Diclofenac Gel

Strong evidence supports the use of topical diclofenac in the treatment of acute pain due to sprains and strains (21). Diclofenac Emulgel and diclofenac Flector plasters are particularly effective for this use case.

Diclofenac gel has also been shown to relieve sharp neck pain (7). In one study, subjects with intense neck pain used diclofenac diethylamine (DDEA) 1.16% gel. Subjects reported that the gel quickly reduced neck pain and improved neck function.

Achilles tendinopathy (CAT), an injury of the Achilles tendon in the heel, can be treated with topical diclofenac (22). In a pilot study, topical diclofenac gel substantially reduced chronic CAT pain when subjects were at rest and when they applied pressure to their Achilles. There were no adverse reactions.

Diclofenac gel is also useful for treating Actinic Keratosis, especially as part of the Solaraze preparation (diclofenac 3% + hyaluronic acid 2.5%) (1). Solaraze works by starving out cells called dysplastic keratinocytes, while causing programmed cell death (23). This clears lesions while generating little to no inflammation as a by-product.


Diclofenac gel helps alleviate several kinds of musculoskeletal pain and carries fewer side effects other NSAID medications.

How to Use Topical Diclofenac Solutions

Diclofenac gel must be prescribed by a medical professional. Consult with a doctor to determine the diclofenac solution that is right for you, and always follow the accompanying medication guide.

Voltaren and Pennsaid should be applied to clean, dry skin (24). Avoid showering or bathing for at least 30 minutes after applying these medications. Do not apply a bandage or dressing to the treated area, and avoid heat. Try to maintain a regular application schedule.

Be careful to avoid the eyes, nose, and mouth. Rinse with water or a saline solution if the medication gets in your eyes. If your eyes are still irritated after an hour, call poison control.

Avoid applying diclofenac gels and liquids to peeling, infected, swollen or broken skin. Do not apply to open wounds or areas covered with a rash, as doing so may irritate the skin.

Before using diclofenac gel, patch-test by applying the gel in a small area at first. If the skin shows no signs of irritation after 24 hours, the gel should be safe to use.

Store the gel at room temperature and out of the reach of children.


Follow the directions on your dosing card carefully when using diclofenac gel and be sure to apply it to clean, unbroken skin.

Risks and Side Effects

Although topical diclofenac solutions are low-risk, especially compared to oral NSAIDs, there are still possible side effects to consider before using these medications. Always consult with a doctor before using diclofenac solutions.

The most frequent adverse side effect associated with diclofenac gel is irritation at the site of application (25). Dry, itchy, and inflamed skin are the most common reactions reported in clinical studies.

Other minor side effects include constipation, diarrhea, gas, heartburn, nausea, vomiting, and drowsiness (26).

More serious side effects can occur with long-term use. These may include high blood pressure, swelling, renal (kidney) papillary necrosis and other kidney injuries.

Like all NSAIDs, Voltaren gel has black box warnings that alert physicians and patients to the most serious potential side effects, although these rarely occur. These include an increased risk of serious or possibly fatal cardiovascular events, heart attack or stroke. They also warn of serious gastrointestinal events including bleeding, ulcers, and perforation of the stomach and intestines.

Diclofenac gel can also cause gastrointestinal bleeding in rare cases (27). You should exercise caution if you have a history of stomach ulcers.

In particular, elderly patients suffering from osteoarthritis who have accompanying medical problems should carefully consider the risks before using topical diclofenac solutions, especially if they suffer from impaired renal function, serious heart conditions, hypertension, and liver issues.

Certain People Should Avoid Using Diclofenac Gel

Women who are trying to get pregnant, are pregnant, or are breastfeeding should not use Voltaren, Pennsaid or Solaraze. These medications can delay ovulation, cause fetal heart defect, and harm a nursing infant.

Patients who develop asthma, hives or other allergic reactions when taking aspirin or NSAIDs should not use diclofenac gel.

People with hypersensitivity to diclofenac should not use Voltaren gel.

Drug Interactions

Diclofenac gel should not be used in conjunction with aspirin or oral NSAIDs. This can increase the risk of adverse effects.

Other Skin Products

Topical diclofenac solutions should not be used in combination with skin products.

Diclofenac gel should not be used at the same time as cosmetics, sunscreens or moisturizers. These combinations haven’t been tested and may increase risk factors.

Remember to always apply diclofenac solutions to clean, dry skin.


Diclofenac gel comes with certain side effects, most notably skin irritation at the site of application, but is relatively safe overall. It should not be combined with oral NSAIDs or skin care products.


Diclofenac gel is a safe and effective option for treating joint pain, especially in cases of arthritis. It can also be used to treat acute neck pain, back pain, tendonitis, and sprains and strains.

It’s particularly useful for people with high blood pressure or heart disease, for whom oral NSAIDs are not recommended.

Diclofenac gel must be prescribed by a doctor. Voltaren and pennsaid are the most common brand names. Voltaren gel is often suggested for joint pain in the hands, fingertips, knees, hips, and spine (neck and lower back), while Pennsaid is often suggested for knee pain.

Topical diclofenac largely carries the same side effects as oral NSAIDs. However, diclofenac gel may result in more serious gastrointestinal side effects than oral NSAIDs. There have been few reports of major side effects thus far.

The elderly and those with more than one chronic disease should be cautious when using diclofenac gel. Women trying to get pregnant, pregnant women, and women who are nursing should not use diclofenac gel.

Diclofenac gel can be a helpful option for relieving joint pain and discomfort. Talk to your doctor to see if it might be right for you.

The information provided in this article is not a substitute for professional medical advice, diagnosis, or treatment. You should not rely upon the content provided in this article for specific medical advice. If you have any questions or concerns, please talk to your doctor.

Research Citations

Researched, written, and reviewed by:
Natalie Pertsovsky
Researcher and author
Natalie is a freelance writer with experience at a number of publications, including Bloomberg and The Rooster Magazine. She holds a degree in Journalism from Northwestern University.
Read full bio
Dr. Juliana Bruner, DPT
Researcher and author, Physical Therapist
Dr. Bruner is a physical therapist who is highly trained and skilled in helping people overcome their physical ailments to live the best life they can. She is also a writer who enjoys spreading knowledge about various topics in the PT and healthcare industry.
Read full bio
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This article contains scientific references. The numbers in the parentheses (1, 2, 3) are clickable links to peer-reviewed scientific papers.