Topical Nonsteroidal Anti-Inflammatory Drugs: The Importance of Drug, Delivery, and Therapeutic Outcome

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used in the treatment of pain associated with a variety of indications, including arthritic conditions, but their usefulness is often limited by dose-dependent adverse events (AEs), such as gastrointestinal disturbances, cardiovascular events, and renal toxicity. The risk of such effects could be reduced by the use of topical formulations, which offer the potential to deliver analgesic concentrations locally, at the site of inflammation, while minimizing systemic concentrations. The topical preparations currently approved in the United States are diclofenac sodium 1.5% topical solution (containing dimethyl sulfoxide as a penetration enhancer), diclofenac sodium gel 1%, and a diclofenac hydroxyethylpyrrolidine 1.3% patch. Each of these topical NSAIDs provide drug delivery to subcutaneous tissues for the management of pain associated with osteoarthritis or soft-tissue injuries. Furthermore, these formulations are not significantly associated with the systemic AEs associated with oral NSAIDs; the most common AEs associated with topical formulations are local skin reactions, which are usually mild and self-limiting. Other topical NSAID preparations approved in the European Union include ibuprofen creams and gels, ketoprofen gel, felbinac gel and cutaneous foam, and piroxicam gel. Meta-analyses have confirmed the efficacy and safety of these preparations. However, it is important to recognize that pharmacokinetic absorption from topical formulations can vary markedly, even between different formulations of the same drug, depending on the agent, the underlying disorder, and the site of application. It is therefore essential to consider the patient, the drug, and the drug delivery mechanism when selecting a topical NSAID preparation.