An alternative topical treatment of osteoarthritis of the knee with cutaneous diclofenac solution

Abstract

Background: Osteoarthritis (OA) is the most common chronic degenerative disease, which is characterised by the destruction of the articular cartilage and subchondral bone. The current treatment of OA is based primarily on the use of nonsteroidal anti-inflammatory drugs (NSAIDs) and analgesics. There are disadvantages to routinely using NSAIDs in OA. Topical NSAIDs represent a potentially important advance in this regard as they may be significantly safer than oral NSAIDs. Cutaneous diclofenac solution (Pennsaid®) was developed for the treatment of symptomatic OA of the knee and contains diclofenac sodium as an active ingredient and dimethyl sulfoxide (DMSO), a penetration enhancer. Objective: To review: i) dermal drug application; ii) the treatment of OA with systemic and topical NSAID therapies; and iii) the clinical efficiency of Pennsaid on the topical treatment of OA of the knee. Methods: A literature search was carried out on skin, topical drug delivery, treatment of OA and assessment of published clinical studies with Pennsaid. Results and discussion: The clinical studies showed that applying the topical diclofenac solution (Pennsaid) to a painful knee with primary OA could provide symptom relief equivalent to oral diclofenac with minimal systemic side effects; however, studies are needed that compare the effectiveness of Pennsaid with different topical forms of diclofenac.