Topical (rub on) Pain Medicines

When experiencing joint or muscle aches and pains, many people seek relief from an oral pain medication, such as acetaminophen (e.g. Tylenol) or ibuprofen (e.g. Motrin).  An alternative to this, particularly well suited in someone who cannot tolerate these medications, are topical pain medicines (analgesics).  Topicals, which are applied directly to the skin, come in several preparations including gels, solutions, and sprays. Some of the most common applications for topical analgesics are joint pain associated with arthritis, nerve-related pain, and muscle soreness after physical exertion.

What's in over-the-counter (OTC) topical analgesics?  Several topical are available on an OTC basis. The active ingredients in these fall into a few general categories.
 
Counterirritants (Icy Hot, Biofreeze, others) These topicals work primarily by creating a burning or cooling sensation that distracts the user from the painful stimulus. The active ingredients in these medications include methylsalicylate, menthol, and camphor. This class of analgesics has no effect on the underlying inflammation associated with arthritis and work primarily at the level of the superficial nerve fibers.

Salicylates  (Aspercreme, Bengay, others)  The most well-known salicylate is aspirin. When absorbed through the skin, however, creams containing salicylates can provide some of the same pain-reducing effect as oral aspirin.  This class of topical analgesics may be particularly beneficial with arthritis pain in the fingers and knees.
   
Capsaicin  (Zostrix, Capsagel, others)  Capsaicin is the chemical that makes chili peppers hot.  When applied topically, it works by decreasing a chemical in the body (substance P) that is involved in sending pain signals to the brain. Capsaicin analgesics may be used to treat minor pain associated with arthritis or muscle strains.  Topical analgesics of this class also work well for a type of persistent nerve pain following a bout of shingles (post-herpetic neuralgia).

Are prescription topicals available?  Oral medications in a class of drugs known as non-steroidal anti-inflammatory drugs (NSAIDs) are widely used to treat pain and inflammation.  Ibuprofen (Advil, Motrin), naproxen (Aleve, Naprosyn), celecoxib (Celebrex) and indomethacin (Indocin) are examples of drugs in this class.  Taken orally, however, these drugs can produce serious side effects including stomach ulcers, liver or kidney failure, and may increase one's risk of having a heart attack.  In the U.S. a prescription topical that contains the NSAID, diclofenac (Voltaren Gel 1%) has been approved by the Food and Drug Administration for the treatment of osteoarthritis in joints close to the skin's surface, such as the hands and knees. A potential benefit of topical administration of this product is the avoidance of many of the side effects associated with oral NSAIDs.

How well do they work?   At the risk of sounding like a TV ad for a medication--- "your results may vary". Much of the evidence for the effectiveness of OTC topical analgesics is anecdotal, coming from users of the various products. Results of scientific studies evaluating the effectiveness of OTC topical analgesics have generally shown only modest improvements in symptoms.  In regard to a topical containing the prescription medication diclofenac (e.g. Voltaren gel), however, there is stronger data supporting its effectiveness. In an analysis of multiple studies performed by an international body of health experts, topical diclofenac solution was found to be equally effective to that of oral NSAIDs in knee and hand osteoarthritis while producing a lower incidence of gastrointestinal problems.

Are topical analgesics safe to use? Like any other medication, topical analgesics can have side effects or cause allergic reactions.  The most common side effect, particularly with capsaicin-containing products, is a local skin reaction at the site of application. These medicines should not be applied to broken skin or to mucous membranes.  It is important to let your doctor known if you are using any of the OTC products while taking other medications since it is possible for a drug-drug interaction to occur.  Someone taking blood thinners needs to be particularly careful when using a salicylate-containing product since the combination can increase the risk of bleeding.

Sources for article:
Rub-on pain reliever can ease arthritis discomfort from Harvard Health Publications
Topical NSAIDs for chronic musculoskeletal pain in adults from the Cochrane Library
Arthritis pain: Treatments absorbed through your skin from the Mayo Foundation for Medical Education and Research

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Kent Davidson MD - Health Tip Content Editor
Reviewed and Approved by Charles W. Smith MD, Medical Director on 6-8-2016