Over-the-counter topical diclofenac in musculoskeletal pain: clinical value, access and responsible use

Topical non-steroidal anti-inflammatory drugs (NSAIDs), including diclofenac, are established options for localized musculoskeletal pain, with guidelines supporting their use in knee osteoarthritis, broader osteoarthritis management and acute non-low-back musculoskeletal injuries. For selected indications, topical diclofenac can be highly effective and is generally well tolerated when used as indicated. It provides local analgesic and anti-inflammatory activity with substantially lower systemic exposure than oral NSAIDs, which may be particularly relevant for older adults and people with gastrointestinal, cardiovascular, renal or polypharmacy-related risk factors. As an NSAID, topical diclofenac should nevertheless be used in accordance with product labeling.These clinical benefits sit alongside environmental considerations. Diclofenac may enter wastewater via excretion, and for topical products, through handwashing, wash-off from treated skin, and improper disposal. National exposure estimates suggest that topical formulations can make an important contribution to diclofenac entering wastewater and surface waters, although estimates are setting-specific and depend on assumptions about use, wash-off and wastewater removal.This commentary considers the clinical value of over-the-counter (OTC) topical diclofenac alongside environmental evidence and uncertainties relevant to responsible use. Integrated evidence comparing analgesic options across clinical outcomes, patient safety, environmental burden and substitution effects remains limited, and the net consequences of treatment substitution cannot currently be reliably assessed. Some practical measures can reduce diclofenac release through specific point-of-use pathways, although their uptake and population level impact require further evaluation.Topical diclofenac therefore provides a useful case study for responsible, pharmacist-guided OTC self-care in musculoskeletal pain management. In the authors' opinion, the available evidence and remaining uncertainties call for proportionate stewardship: maintaining clinically appropriate OTC access to topical diclofenac while avoiding unnecessary use and supporting label-consistent treatment, patient education, and feasible measures to reduce avoidable environmental release, alongside formulation and delivery innovation.