Tolerability of diclofenac sodium 1% gel with concomitant medications known to interact with diclofenac

Multidisciplinary Guidelines for the Rational Use of Topical Non-Steroidal Anti-Inflammatory Drugs for Musculoskeletal Pain (2022)

(1) Background: Topical non-steroidal anti-inflammatory drugs (NSAIDs) are one of the primary drugs for treating musculoskeletal pain. However, there are currently no evidence-based recommendations about drug selection, drug administration, drug interactions, and use in special populations or other pharmacology-related content of such medications. To this end, the Chinese Pharmaceutical Association Hospital Pharmacy Professional Committee developed multidisciplinary guidelines on using topical NSAIDs to treat musculoskeletal pain. (2) Methods: The guidelines development process followed the World Health Organization guideline development handbook, the GRADE methodology, and the statement of Reporting Items for Practice Guidelines in Healthcare. The guideline panel used the Delphi method to identify six clinical questions to be addressed in the guidelines. An independent systematic review team conducted a systematic search and integration of evidence. (3) Results: Based on the balance between the benefits and harms of an intervention, the quality of the evidence, patient preferences and values, and resource utilization, the guideline panel developed 11 recommendations and nine expert consensuses on using topical NSAIDs to treat acute and chronic musculoskeletal pain. (4) Conclusions: Based on the effectiveness and overall safety of topical NSAIDs, we recommend patients with musculoskeletal pain use topical NSAIDs and suggest high-risk patients use topical NSAIDs, such as those with other diseases or receiving other concurrent treatments. The evidenced-based guidelines on topical NSAIDs for musculoskeletal pain incorporated a pharmacist perspective. The guidelines have the potential to facilitate the rational use of topical NSAIDs. The guideline panel will monitor the relevant evidence and update the recommendations accordingly.

Transdermal Permeation and Skin Retention of Diclofenac and Etofenamate/Flufenamic Acid From Over-the-Counter Pain Relief Products

Topical pain relief products differ in the type of drug, concentration, and formulation. All these factors influence the drug transit through the skin barrier, and its eventual retention in the skin as a reservoir for subsequent release. In addition, the drug potency can be different, which is important for the product efficacy. We studied here ex vivo human skin permeation and retention of five over-the-counter NSAID gels containing 2.32% diclofenac (DIC) and 5-10% etofenamate (ETF). The potency of the permeated/retained drug amounts were compared using a composite parameter, the Index of Relative Topical Anti-inflammatory Activity (IRTAA), which is calculated as the product of the skin permeation/retention and the drug relative potency. The IRTAAs of the DIC gel were 94-667-fold higher and 72-208-fold higher for transdermal delivery and skin retention, respectively, than IRTAAs of the ETF gels. These superior IRTAAs indicate that DIC delivered by this topical formulation would achieve a higher bioactivity and would form a potent drug reservoir relevant for its subsequent long-lasting release.