Pain management in osteoarthritis: the role of COX-2 inhibitors

Abstract

Pain is the major symptom that leads patients to consult their physicians for the treatment of arthritis; therefore, effective pain control is an important goal in the management of this disorder. Pharmacologic therapy begins with simple analgesics and education. In many patients, simple analgesics do not adequately control moderate arthritis pain, and nonsteroidal antiinflammatory drugs (NSAID) are substituted for or added to the analgesic therapy. While NSAID are effective in controlling pain in mild to moderate osteoarthritis (OA), they are associated with significant toxicity (most frequently gastrointestinal) and may even cause complications that result in death. Patients who experience the pain associated with arthritis would therefore benefit from the antiinflammatory and analgesic actions of agents that are devoid of significant toxicities. Cyclooxygenase-2 (COX-2) inhibitors are being evaluated in clinical trials or are in development. These agents appear to inhibit only the COX-2 isoenzyme, which is produced largely during inflammation and is responsible for the biosynthesis of prostaglandins and other mediators of inflammation as well as sensitizers to pain. Because COX-2 inhibitors do not inhibit COX-1 isoenzyme activity at pharmacologic concentrations, they are devoid of many of the toxicities that are typical side effects of NSAID. Short term studies in dental pain, OA, and rheumatoid arthritis found that the COX-2 inhibitor celecoxib was an effective analgesic but did not cause gastroduodenal erosions. It has the potential to provide analgesia and antiinflammatory action in patients with arthritis without the side effects of NSAID. Further studies are required to substantiate these findings.