How Do Topical Pain Killers Actually Work?

The Common Types Of Topical Pain Killers

Topical pain killers come in several different forms, ranging from being available as a rub on, roll on, spray on liquid or creams, as well as coming in adhesive long lasting topical patch form which can be placed on the site of discomfort. There are many different options on the market of topical agents approved by the TGA to provide pain relief for common musculoskeletal complaints.  Many of these products use different active ingredients to achieve their desired result. The most common types of active ingredients of over the counter (non-prescription) creams available include:

• Counterirritant creams
• Salicylates
• Capsaicin
• and non-steroidal anti-inflammatory medicines

Each one explained in a little more detail:

Counterirritants – Creams or patches using a counterirritant have ingredients such as menthol, methylsalicylate (oil of wintergreen), camphor, eucalyptus oil… These agents make the skin feel hot or cold, and it’s thought that these creams distract your mind from the sensation of pain and this is how they provide some temporary pain relief. Examples of such creams include:

• Deep Heat which contains methyl salicylate and menthol and Tiger Balm which contains the active ingredients of camphor and menthol cajuput oil and clove oil.

Salicylates – As an active ingredient in creams is the same as what gives Aspirin its pain relieving quality and is a mild non-steroidal anti-inflammatory drug (NSAID) that can be useful in providing temporary relief of minor aches and pains. When salicylates are absorbed into the skin they may help with managing pain particularly when the target area is close to the surface of the skin. Meaning areas such as the fingers, elbows and knees are most likely to have a positive effect with these creams probably more so than the back or neck where often the area causing the pain lies somewhat deeper.

• Aspercreme and Myoflex Cream which contain Trolamine Salicylate are examples of salicylate creams.

Capsaicin – Capsaicin is the main ingredient of hot chili peppers and is one of the most effective ingredients for topical pain relief creams and patches. Creams containing capsaicin will create a a warm-hot, tingling or burning sensation. Capsaicin applied to the skin depletes a chemical (substance P) in nerve cells that helps send pain signals to the brain and therefore again helps temporarily manage mild pain.

• Zostrix HP Cream which contains capsaicin and Glucosamine Rapid which contains glucosamine sulfate and capsicum are examples of capsaicin based pain relief creams.

Non-steroidal anti-inflammatory – These are topical substances that contain an anti-inflammatory medicine such as ibuprofen, diclofenac, felbinac, ketoprofen, or piroxicam and come in various different brand names. These creams work by blocking the effect of chemicals called cyclo-oxygenase (COX) enzymes. COX enzymes help to make other chemicals called prostaglandins. Some prostaglandins are involved in the production of pain and inflammation at sites of injury or damage. And as a result a reduction in prostaglandin production via the use of non-steroidal anti-inflammatory medications reduce pain and inflammation. By using a topical preparation means that the total amount of “anti-inflammatory” medication in your body is very low, and as a result you are much less likely to have any side-effect using this sort of medication topically rather than orally.

• Example creams in Australia include gels such as Voltaren Emulgel which contains Diclofenac Diethylammonium Gel, and Nurofen Gel which contains ibuprofen.

Do Topical Creams And Patches Work?

There is little evidence to suggest they do. A systematic review in 2009 found little evidence that over the counter sports creams using salicylates have any effect at all on muscle aches and pain when compared with a placebo. Another comprehensive review of research on over the counter sports creams containing salicylates as the main active ingredient found them not to be effective. However, there is some evidence to suggest that topical local anesthetics, topical capsaicin, and some topical NSAIDs creams may reduce muscle pain from strains and sprains.

Are Topical Pain Killers Safe?

When used in accordance with the label directions over the counter topical pain killers are relatively safe, however they should not be used long term or in excessive quantities without medical advice. .
Some of the common side effects of topical pain relief agents can include:

• Burning
• Stinging
• Irritated skin

Some Basic Topical Cream House Keeping Rules

As a rule never use these medications on broken or irritated skin, and do not use heat on your injury if you have applied these topical medications. The use of applied heat in addition to these agents can potentially increase the risk of burns. Remember to always wash your hands thoroughly following application to avoid accidental ingestion or application to the eyes.  Creams containing salicylates should not be used by those who are allergic to aspirin and do not apply topical creams with methyl salicylate before you exercise because your body could wind up absorbing too much of the active ingredient as exercising may increase your circulation to this area.

Worth Noting: If you are not getting relief from the topical products you are using don’t simply use more, overdoing it could put you at a greater risk of burns and or allergic reactions. If this is the case then it is best to seek medical attention / opinion. As is generally the case should symptoms persist.

Professionally my personal opinion is that some of these topical creams have a place in assisting people manage mild symptoms and can play a role in physio rehab of many musculoskeletal conditions and it isn’t uncommon that I would recommend as such in one of my treatment sessions. Used appropriately I find them to be safe with minimal risk of side effects and in the right situation positively impactful on the rehabilitation process.

Disclaimer: Always talk to your doctor prior to starting any medication and topical pain killers are no exception to this rule. Sydney Physio Clinic does not endorse any treatments, procedures, products mentioned. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific orthopaedic advice or assistance on How Do Topical Pain Killers Actually Work? should consult his or her general practitioner or physiotherapist.