Tuesday, June 16, 2015

Topical non-steroidal anti-inflammatory drugs for acute musculoskeletal pain in adults

Cochrane: Acute musculoskeletal pain describes conditions like a sprained ankle or a muscle pull. These usually get better over two or three weeks without treatment, but can be very painful while they last. Topical non-steroidal anti-inflammatory drugs (NSAIDs) are applied to unbroken skin where it hurts as gels, creams, sprays, or plasters. Topical NSAIDs penetrate the skin, enter tissues or joints, and reduce processes causing pain in the tissue. Drug levels in the blood with topical NSAIDs are very much lower than with the same drug taken by mouth. This minimises the risk of harmful effects.

We searched medical databases for clinical trials comparing topical NSAIDs with placebo (creams or gels that do not contain a medicine) or other medicines in adults aged 16 years or older with musculoskeletal pain (typically sports injuries). The evidence is current to February 2015.

This review is an update of 'Topical NSAIDs for acute pain in adults' originally published in Issue 6, 2010.

We identified 14 new studies to add to the 47 studies included in the earlier review. We also identified 14 studies in a clinical trial registry that are completed and three short reports from meetings, for which we could not find full details (about 4500 participants). Three more studies are ongoing (almost 900 participants).
The 61 included studies, involving 8386 participants, were generally of high-quality. They tested a number of different topical drugs, mostly against a topical placebo (carrier without the NSAID), with application at least once a day. We were interested in participants having good pain reduction (by about half) around seven days after treatment started. At later times, most people are expected to get better even without treatment.
We looked at particular formulations of individual drugs. Gel formulations of diclofenac and ketoprofen were among the most effective, along with ibuprofen gel and diclofenac plaster. For diclofenac and ketoprofen gels, 7 or 8 people out of 10 with a painful strain, sprain, or muscle pull had much reduced pain after seven days, compared with only 2 or 3 out of 10 with placebo (high quality data). Other NSAIDs and formulations were better than placebo, but not by as much. Because both topical NSAIDs and topical placebo are rubbed into the skin in these studies, we know that any effect is not just from rubbing.
About 1 in 20 people experienced a mild and short-lived side effect like redness at the application site. This was the same for topical NSAID and topical placebo (high quality data). Side effects like a stomach upset or feeling sick were uncommon, with no difference between topical NSAID and topical placebo (high quality data). There were no serious side effects.

Authors' conclusions: 

Topical NSAIDs provided good levels of pain relief in acute conditions such as sprains, strains and overuse injuries, probably similar to that provided by oral NSAIDs. Gel formulations of diclofenac (as Emugel®), ibuprofen, and ketoprofen, and some diclofenac patches, provided the best effects. Adverse events were usually minimal.
Since the last version of this review, the new included studies have provided additional information. In particular, information on topical diclofenac is greatly expanded. The present review supports the previous review in concluding that topical NSAIDs are effective in providing pain relief, and goes further to demonstrate that certain formulations, mainly gel formulations of diclofenac, ibuprofen, and ketoprofen, provide the best results. Large amounts of unpublished data have been identified, and this could influence results in updates of this review.