When Topical Pain Relief Gets Under Your Skin: The Risks of Voltaren Gel

If you can’t tolerate ibuprofen, naproxen, celecoxib, meloxicam or other oral anti-inflammatory drugs, rubbing a medicine onto an aching joint instead of swallowing a pill sounds like an ideal solution. And for many people, it is. Voltaren Arthritis Pain Gel has become one of the most successful over-the-counter pain-relief brands in the world. But the risks of Voltaren Gel remind us of something that is easy to forget: medicine applied to the skin does not necessarily stay on the skin.

Voltaren Arthritis Pain Gel contains diclofenac, a nonsteroidal anti-inflammatory drug (NSAID). It can ease arthritis pain in fingers, hands, wrists, elbows, feet, ankles and knees. Because much less diclofenac gets into the bloodstream from a topical gel than from a pill, systemic side effects should be less likely.

That’s the good news! The surprise is that some people seem remarkably sensitive to even the relatively small amount that gets through the skin.

A recent question to our nationally syndicated newspaper column illustrates the dilemma perfectly.

Q. I have had reflux for decades and I can’t tolerate oral NSAIDs under any circumstances. However, I have successfully used Voltaren Arthritis Pain gel on small joints such as my big toe. I have had no digestive side effects as a result. I used the gel several times a day for three months and got rid of the pain. I use it off and on for other minor arthritis flareups.

A. Hundreds of readers have shared their experience with topical diclofenac gel. Many report good pain relief without side effects. But some sensitive people report digestive upset or elevated blood pressure.

One person, a registered nurse, said:

“I can’t take NSAIDs by mouth, so I was excited to try Voltaren on my painful knee. I applied it before leaving for my shift. Half an hour later, my stomach started to bother me. I was really sick all day and never tried the gel again.”

Another reader used the gel for his knee pain. After three weeks, the leg swelled and his blood pressure hit 220/110.

You can read about the pros and cons of diclofenac, both oral and topical, in our eGuide to Alternatives for Arthritis. It also contains information on many other approaches to easing joint pain. This online resource may be found under the Health eGuides tab.

So how can one person who cannot tolerate oral NSAIDs use topical diclofenac for months without trouble, while another reacts badly after one application? We wish we knew.

Why Should the Risks of Voltaren Gel Be Lower?

There is a sound pharmacological reason to prefer a topical NSAID over an oral one for localized arthritis pain. Swallow a diclofenac pill and the medicine is absorbed through the digestive tract and distributed throughout the body. Apply diclofenac to a knee, and a much smaller amount reaches the general circulation.

The official prescribing information provides some surprisingly useful numbers:

“Systemic exposure with recommended use of VOLTAREN® GEL (4 x 4 g per day applied to 1 knee) is on average 17 times lower than with oral treatment. 

“The amount of diclofenac sodium that is systemically absorbed from VOLTAREN® GEL is on average 6% of the systemic exposure from an oral form of diclofenac sodium.

“The average peak plasma concentration with recommended use of VOLTAREN® GEL (4 x 4 g per day applied to 1 knee) is 158 times lower than with the oral treatment.”

Six percent sounds reassuring. It is! But six percent is not zero.

That may help explain why someone who gets terrible heartburn from an ibuprofen or naproxen pill can sometimes use Voltaren Gel comfortably, while another person experiences surprisingly similar symptoms from both oral and topical NSAIDs.

The Risks of Topical Voltaren Gel: A Huge Contradiction

If a physician were to prescribe 1% VOLTAREN® GEL (diclofenac sodium topical gel) there is a boxed warning:

“WARNING: RISK OF SERIOUS CARDIOVASCULAR AND GASTROINTESTINAL EVENTS

But wait…there’s more. Here are additional warnings that the FDA requires for prescription Voltaren Gel:

“WARNINGS AND PRECAUTIONS

That is more than a little intimidating.

When diclofenac 1% gel was granted over-the-counter drug status as Voltaren Arthritis Pain Gel, the boxed warning disappeared. In other words, the same medicine in the same strength that is available without a prescription has a much weaker warning.

Here are some of the warnings listed in DailyMed for OTC Voltaren Arthritis Pain:

“Liver warning: This product contains diclofenac. Liver damage may occur if you apply

• more or for a longer time than directed

• when using other drugs containing diclofenac

“Stomach bleeding warning: This product contains an NSAID, which may cause severe stomach bleeding. The chance is small but higher if you

• are age 60 or older

• have had stomach ulcers or bleeding problems

• take a blood thinning (anticoagulant) or steroid drug

• take other drugs containing prescription or nonprescription NSAIDs (aspirin, ibuprofen, naproxen, or others)

• have 3 or more alcoholic drinks every day while using this product

• apply more or for longer than directed

“Heart attack and stroke warning: NSAIDs, except aspirin, increase the risk of heart attack, heart failure, and stroke. These can be fatal. The risk is higher if you use more than directed or for longer than directed.”

There is quite a difference between the FDA-mandated warnings for 1% Voltaren Gel prescribed by a doctor and 1% Voltaren Gel purchased over the counter.

Does Topical Diclofenac Actually Work?

There is reasonably good evidence that it does. A 2025 meta-analysis analyzed 12 randomized controlled trials of topical diclofenac gels, solutions and patches for knee osteoarthritis. The investigators found that all three formulations reduced pain and improved function compared with placebo. Systemic side effects remained uncommon in the clinical trials (BMC Musculoskeletal Disorders, March 10, 2025).

That scientific evidence mirrors what we have heard from readers for decades.

One woman told us:

“Both my husband and I have been using a small amount of Voltaren gel for years. This has enabled me to avoid knee replacements and my husband, back surgery.”

She reported that their kidney function remained normal during their annual examinations.

Another reader told us:

“I have been buying Voltaren Gel in Germany and Mexico and St. Maarten while traveling. It has worked great for me and my friend who has rheumatoid arthritis.”

Whitley in North Carolina was equally enthusiastic:

“I get 5-6 hours of excellent pain relief from Voltaren Gel…After 9 years I’ve had zero negative reactions.”

We have received far more positive reports about topical diclofenac than negative ones. For some people, the ability to rub an anti-inflammatory drug directly onto an aching joint without the stomach distress they experience from pills is a godsend.

That is only half the story, however.

The Risks of Voltaren Gel Can Include Digestive Distress:

This is one of the reactions we hear about: People often turn to topical diclofenac precisely because oral NSAIDs cause indigestion, reflux or stomach pain.

Eric wrote:

“I was prescribed Voltaren Gel for treatment of persistent groin pain related to a running injury. It did offer some relief, but I had serious gastrointestinal discomfort: gas, heartburn and painful swallowing. These side effects would clear up within a day or two after discontinuing use of the product.”

Rosanna had a similar experience:

“My orthopedic doctor prescribed generic Voltaren Gel for my knee pain because I cannot take oral NSAIDs. I have applied it only three times to my knees, and I am now suffering from acid reflux and a burning sensation in my digestive tract.”

Carol’s experience was even more alarming.

She had taken oral NSAIDs for years before deciding that they had taken too great a toll on her digestive tract. Later, she tried Voltaren Gel on her knee. She developed acid indigestion with such intense chest pain that she thought she was having a heart problem. A cardiac CT scan found no explanation. She stopped the Voltaren Gel and told us that she did not experience the chest pain again.

Such stories cannot prove that topical diclofenac was responsible. Anecdotes do not establish cause and effect. But the experiences are biologically plausible because we know that diclofenac gets through the skin and into the bloodstream. The OTC packaging contains a warning about stomach bleeding.

Can Voltaren Gel Raise Blood Pressure?

Of all the risks of Voltaren Gel, this may be the one that surprises people most.

One reader told us:

“Six years ago, my doctor prescribed Voltaren Gel for arthritis in my knee. She assured me that the warnings only applied to the oral form of the drug. I got excellent relief.

“After three weeks, however, I suddenly developed swelling in that leg. My blood pressure went up to 220/110 and I ended up in the ER. They monitored me for 6 or 7 hours until my blood pressure returned to normal. Voltaren, even topical, can cause some serious side effects.”

Another reader reported:

“Voltaren gel helped my sore knee. But it also raised my blood pressure to 209/91 and caused Afib. I never experienced anything so scary in my life.”

Such reactions appear to be unusual, but they should not be dismissed simply because the drug was applied to the skin.

The official prescribing information for Voltaren Gel warns that NSAIDs can cause new hypertension or worsen existing high blood pressure. It also cautions about fluid retention, edema and heart failure.

People who already have hypertension may want to monitor their pressure after starting topical diclofenac, particularly if they are using it regularly.

What About the Kidneys?

This has been an especially controversial question. Oral NSAIDs can interfere with prostaglandins that help maintain adequate blood flow through the kidneys. That is one reason doctors are often cautious about prescribing such drugs to people with kidney impairment.

Since much less diclofenac reaches the circulation from a topical product, you would expect kidney risk to be lower. A systematic review supports that conclusion, but with an important qualification (Medicina (Kaunas), August 21, 2026).

The investigators analyzed 18 studies with data from more than 500,000 participants. In people without special kidney risk, topical diclofenac produced little or no change in standard measures of kidney function and had substantially smaller renal effects than oral diclofenac.

In people who were already vulnerable to kidney injury, however, the evidence was a little less reassuring.

The authors concluded:

“In adults with increased renal risk, the evidence is of moderate certainty and is based primarily on observational data and subgroup analyses. These suggest a modest increase in AKI [acute kidney injury] with topical NSAID exposure overall, while also indicating a consistently lower relative risk compared with systemic NSAID use. However, the available data are indirect for diclofenac specifically and do not include systematic measurement of sensitive renal biomarkers.”

That’s pretty stuffy doctorspeak. I interpret it to mean: kidney risk with topical diclofenac appears to be reduced rather than absent.

That distinction matters when we consider a report like this one:

“I quit oral NSAIDs several years ago as my doctor advised because of early stage kidney disease. After a bad knee injury, a specialist put me on Voltaren Gel for 9 months. Now I am in stage 4 kidney disease. I had been stable for several years before the daily use of Voltaren Gel.”

We cannot know whether topical diclofenac caused that person’s kidney deterioration. Chronic kidney disease can worsen for many reasons. But someone who already has impaired kidney function should not automatically assume that an over-the-counter topical NSAID is completely harmless.

Sometimes the Problem Is Right on the Skin:

Not all adverse reactions involve absorption into the bloodstream.

Marilyn told us:

“My doctor prescribed Voltaren Gel since pain meds upset my stomach. It didn’t upset my stomach, but on the fourth day of applying it, I broke out in a rash all over my arms and legs. I had to stop using it.”

Skin reactions are among the better-recognized complications of topical diclofenac. Someone who develops a significant rash, blistering or another allergic reaction after applying Voltaren should stop and seek medical advice promptly.

Why Can’t We Predict Who Will React?

This is the question we would most like researchers to answer. Some readers have used topical diclofenac for years and report excellent pain relief without changes in their blood pressure, kidney function or digestive tract.

Others tell us that a few applications trigger heartburn, abdominal discomfort, swelling or a dramatic increase in blood pressure. Why?

Individual sensitivity almost certainly matters. So do dose, frequency of application, how much skin is covered, age, kidney function, cardiovascular health and other medications. We do not know of a simple test that can predict who will get wonderful pain relief and who will develop an unpleasant reaction.

That is why paying attention to symptoms matters.

More Isn’t Necessarily Better:

There is another misconception worth addressing. Because Voltaren Gel is sold without a prescription, some people may assume they can spread it whenever and wherever something hurts. That is not what the product is designed for.

The OTC formulation is intended for arthritis pain in joints such as the hands, wrists, elbows, feet, ankles and knees. People should follow the package directions carefully and should not assume that using extra gel, covering more body surface or continuing treatment indefinitely will produce better results.

The Bottom Line on the Risks of Voltaren Gel:

We remain enthusiastic about topical NSAIDs for the right person. The pharmacology makes sense. You put the anti-inflammatory medicine close to the painful joint and expose the rest of the body to substantially less drug than you would get from a pill. For many people, that strategy works extremely well.

The mistake is assuming that topical means risk-free. It doesn’t. Diclofenac penetrates the skin. A relatively small amount reaches the bloodstream. Most people apparently tolerate that exposure without difficulty, but a few seem exceptionally sensitive.

People who develop unexpected heartburn, stomach pain, swelling, a rash or a significant increase in blood pressure after starting Voltaren Gel should not automatically dismiss those symptoms because “it’s only topical.” Anyone with kidney disease, cardiovascular disease, hypertension, a history of ulcers or serious reactions to NSAIDs should discuss topical diclofenac with a knowledgeable healthcare professional before using it regularly.

And please do not stop a prescribed medicine or make major changes in your arthritis treatment without consulting your physician or pharmacist.

Final Words:

You can learn more about oral and topical NSAIDs as well as nondrug approaches to joint pain in our eGuide to Alternatives for Arthritis. It can be found under the Health eGuides tab.

We would also love to hear about your experience. Has Voltaren Gel been a lifesaver for painful joints? Or did you develop an unexpected side effect? Please share your story in the comment section below.