A comparison of the therapeutic efficacy of diclofenac in osteoarthritis: a systematic review of randomised controlled trials.

OBJECTIVE: Diclofenac is a nonsteroidal anti-inflammatory drug (NSAID) commonly prescribed for pain relief in osteoarthritis (OA). The relative efficacy of diclofenac compared to other pain relief medications used in OA (e.g., alternative NSAIDs, cyclooxygenase type 2 [COX-2] inhibitors) is uncertain. The objective of this systematic review is to compare the current evidence on efficacy of diclofenac versus other pain relief medications.

RESEARCH DESIGN AND METHODS: A systematic literature search was carried out for randomised, well controlled clinical trials comparing the efficacy of diclofenac with other pain relief medications in OA (reviews, meta-analyses and n = 1 trials were excluded). The databases searched were EMBASE, Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, and Ovid MEDLINE Daily Update. Articles were included from 1999 onwards. Retrieved articles were discussed by comparator medication.

RESULTS: Of the 263 articles identified in the literature search, 37 were eventually included in this review. These were comparisons with the selective COX-2 inhibitors etoricoxib, celecoxib, lumiracoxib and rofecoxib; comparisons with the NSAIDs aceclofenac, dexketoprofen, etodolac, lornoxicam, meloxicam, nabumetone and nimesulide; and comparisons to acetaminophen, tramadol, diacerein, oxaceprol, oral hydrolytic enzyme therapies, Chinese herbal remedies and castor oil supplementation. Overall, in the majority of the trials at therapeutic doses diclofenac provided similar efficacy to comparator treatments; and in general diclofenac was able to support its position as a reference medication of choice for OA trials.

CONCLUSIONS: The efficacy of diclofenac is largely unchallenged in that it remains as effective as newer pain relief medications employed in OA. A review of the available data demonstrates that diclofenac continues to provide physicians with a benchmark pharmacological treatment for OA.