Can Pain Be Patched Up?

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Clinicians, patients and some experts have viewed transdermal anti-inflammatory patches as a promising way to bypass the side effects and other problems associated with oral and injectable delivery of anti-inflammatory medications.

A systematic review and meta-analysis published in November in the journal Pain Management may give some pause. It found that transdermal anti-inflammatory patches did not have sufficient evidence to support clinically significant impact on managing short-term and long-term musculoskeletal pain.

María Sánchez, Ph.D., from the Department of Health Professions at Manchester Metropolitan University, and researchers from the School of Pharmacy at the University of East Anglia in Norwich, United Kingdom, sought to determine the efficacy of transdermal anti-inflammatory patches in providing pain relief for acute and chronic musculoskeletal conditions. ​ They assessed whether these patches are a viable alternative to traditional oral or injectable anti-inflammatory medications, particularly regarding their effectiveness and potential reduction in adverse events. ​

Transdermal patches have a few advantages over oral medications.The patches can deliver a specific dose of the active ingredient to the site of pain. The delivery of medication avoids first pass hepatic metabolism fluctuations in drug levels and commonly associated adverse effects that are observed with oral and injectable formulations.

This analysis included 23 randomized placebo-controlled trials with 4,729 participants. All the included studies compared the effects of transdermal anti-inflammatory patches to placebo patches for various musculoskeletal conditions. The studies varied in duration, with the longest treatment period being 24 weeks and the shortest 5 days.

The meta-analysis included betamethasone, diclofenac, ibuprofen, ketoprofen and nitric oxide patches. ​ The results indicated that different medications had varying levels of efficacy, with some showing significant benefits over placebo in specific conditions.

Sanchez and the team found low-certainty evidence that these patches may provide clinically long-term pain relief for chronic conditions, although short-term benefits were not clinically significant. In addition, there were ​ no significant medium-term benefits.

The short-term pain relief was statistically significant but not clinically significant. The Cochrane Risk of Bias Tools and the GRADE approach assessed the evidence quality.

Of the drugs included in the trials for the analysis, nitric oxide patches were the most effective in relieving chronic musculoskeletal pain. Specifically, there was low-certainty evidence that nitric oxide patches had a clinically significant effect on movement pain in the long term.

The team highlighted the potential of transdermal patches to reduce adverse events associated with oral medications, such as gastrointestinal and cardiovascular issues. ​ However, local skin irritation was a common adverse event reported.

The findings suggest that clinicians and patients could consider using transdermal anti-inflammatory patches for long-term management of musculoskeletal pain, especially for patients who cannot tolerate oral medications.But the evidence is not strong, and further high-quality research is needed to confirm these results and determine the most effective types of patches and conditions they can treat.