Questioning The Use Of Muscle Rubs

July 8, 2009

There is not enough evidence to support using gels and creams containing

rubefacients for chronic and acute pain, according to a systematic review by

Cochrane Researchers. Rubefacients cause irritation and reddening of the skin,

due to increased blood flow. The review focused on formulations containing

salicylates, which are widely prescribed or sold over the counter as topical

treatments for sports injuries and muscle pain.

" At present, due to a lack of high quality evidence, we can't say exactly how

effective rubefacients are for acute injuries and there are certainly other more

effective treatments which could be prescribed for use in chronic conditions

like osteoarthritis, " says lead researcher , of the Nuffield

Department of Anaesthetics at the University of Oxford in the UK.

There are over a million prescriptions each year for rubefacient gels and creams

such as Movelat. As with Movelat, the rubefacient compounds in many of these

products are salicylates, which, while they are related to aspirin, may not work

in the same way, especially when applied to the skin. They are referred to as

" counter-irritants " because it is thought that they offset localised pain

through local skin irritation.

The review analysed data from 16 trials for acute and chronic pain, which

together included 1,276 people. Only salicylates were studied and trials were

generally small. Results from four studies showed topical salicylates performed

better than placebos against acute pain, but excluding lower quality studies

meant the results were not statistically significant. When used for chronic

conditions, salicylates performed better than placebos. However, only one in six

patients with chronic pain benefited substantially from using the muscle rubs

compared to one in three using non-steroidal anti-inflammatory drugs.

" Larger and higher quality controlled trials of topical rubefacients are needed

to establish whether these treatments really work. We also need more studies on

other rubefacients as we were only able to assess the effectiveness of the

salicylate formulations in this review, " says . " But it is important to

remember that not all analgesic gels or creams are the same, and for others

there is very good evidence of effectiveness. Those will be dealt with in other

reviews presently being finalised. "

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