The changes of diclofenac action with adjuvant applications on rat paw edema

Nonstereoidal anti-inflammatory drugs (NSAIDs) are the most used drug in musculoskeletal disorders, but their systemic adverse effects limit their therapeutic benefit in local inflammation. On the other hand, topical preparations of capsaicinoids are widely used for musculoskeletal disorders as a complementary therapy. In this study, the effects of both topical capsaicinoids containing patch and local subcutaneous capsaicin application on the anti-inflammatory action of NSAID were examined.Carrageenan-induced paw edema of rats was used in the inflammation model. The volume and weight of paw edema and plasma extravasation in the paw were determined after carrageenan injection.The systemic application of diclofenac (3 mg/kg) which is a NSAID, significantly decreased the volume and weight of the paw edema. Topical capsaicinoids containing patch application or local capsaicin injection (2, 10, 20 ?g/paw) alone did not cause any effect on edema volume and weight. However, the combination of diclofenac with topical capsaicinoids containing patch significantly increased the effectiveness of diclofenac on inflammation. Evans blue content of the paws that represents plasma extravasation was decreased by capsaicinoids containing patch with and without diclofenac and diclofenac combination with the lowest dose of capsaicin injection.The results of this study indicate that topical application of capsaicinoids containing patch enhances the anti-inflammatory effect of diclofenac and its beneficial effect may not purely relate to its capsaicin content. In the treatment of local inflammatory disorders, the combination of NSAID with topical capsaicinoids containing patch could increase the anti-inflammatory efficiency of drug without systemic side effects.