Systematic review of topical diclofenac for the treatment of acute and chronic musculoskeletal pain

Abstract

Aim

The objective was to systematically review the efficacy and safety of topical diclofenac in both acute and chronic musculoskeletal pain in adults.

Methods

We used standard Cochrane methods. Searches were conducted in MEDLINE, EMBASE and The Cochrane Register of Studies; date of the final search was November 2018. Included studies were randomized, double blinded, with ten or more participants per treatment arm. The primary outcome of “clinical success” was defined as participant-reported reduction in pain of at least 50%. Details of adverse events (AEs) were recorded.

Results

For acute pain, 23 studies (5170 participants) were included. Compared to placebo, number needed to treat (NNT) for different formulations were as follows: diclofenac plaster, 4.7 (95% CI 3.7–6.5); diclofenac plaster with heparin, 7.4 (95% CI 4.6–19); and diclofenac Emulgel, 1.8 (95% CI 1.5–2.1). 4.1% (78/1919) reported a local AE. For chronic pain, 21 studies (26 publications) with 5995 participants were included. Formulations included gel, solution with or without DMSO, emulsion and plaster. A clinical success rate of ∼60% (NNT 9.5 [95% CI 7–14.7]) was achieved with a variety of formulations. Local AEs (∼14%) were similar for both diclofenac and placebo.

Conclusion

This systematic review of 11,000+ participants demonstrates that topical diclofenac is effective for acute pain, such as sprains, with minimal AEs. The effectiveness of topical diclofenac was also demonstrated in chronic musculoskeletal pain but with a higher NNT (worse) compared with acute pain. Formulation does play a part in effectiveness but needs further studies.

Keywords:

• Systematic review
• acute pain
• chronic pain
• NSAID
• diclofenac
• topical NSAID

Transparency

Declaration of funding

No funds were received for the preparation of this paper. However, the data comes from a larger project commissioned by Glaxo Smith Kline (GSK). GSK have had no influence on the content of this paper and the authors have been given complete freedom to publish their own conclusions.

Author contributions

P.J.W. designed the project, was involved in the choice of included and excluded studies and drafted the paper. J.X. undertook the search for studies, was involved in the choice of included and excluded studies and added to the draft of the paper. Both authors approved the paper for submission.

Declaration of financial/other relationships

P.J.W. has disclosed that he was commissioned by GSK to conduct a systematic review of topical diclofenac products through his business Oxford Systematic Review Services. No potential conflict of interest was reported by J.X. CMRO peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Acknowledgements

None reported.

Notes

i IBSA Institut Biochimique SA, Pambio-Noranco, Switzerland.

ii Biologische Heilmittel Heel GmbH. Baden-Baden, Germany.

iii GSK Consumer Healthcare, Brentford, UK.

iv Dimethaid Research Inc, Ontario, Canada.