Opioids for non-operable osteoarthritis and soft-tissue rheumatism

Moore and McQuay [1], in this issue of Arthritis Research & Therapy, reviewed 34 trials using oral opioids against placebo or a comparator. The review included 5,500 patients; importantly, 4,000 patients contributed to the side-effect profile. It is this profile that is significant in today's world of public and patient safety. Doctors and patients do need help, and preferably evidence, to make choices when treating all types of musculoskeletal conditions. Moore's review highlights two problems: first, that the trials were of short duration, and second, that the side-effect profiles were a problem, causing patient withdrawals of at least 22%.The European League Against Rheumatism recommends opioid analgesics with or without paracetamol as useful alternatives for patients in whom non-steroidal anti-inflammatory drugs (NSAIDs), including cyclo-oxygenase-2 (Cox-2) selective inhibitors, are contra-indicated, ineffective and/or poorly tolerated [2,3].The American Pain Society and the American College of Rheumatology give similar advice for the use of opioids in rheumatoid arthritis (RA) as well as osteoarthritis (OA) [4,5].Trials have shown that opioids are effective in OA and RA and improve sleep and quality of life [6]. If opioids are effective, are they safe? Schug and colleagues [7] showed that they have a good safety record and most have a high therapeutic index. In acute overdose, respiratory failure can occur but there does not seem to be any specific organ toxicity. The side-effects of nausea, vomiting, somnolence and sedation can present problems. It is accepted that patients usually rapidly develop tolerance to these side-effects. Unfortunately, tolerance does not develop for constipation, so this side-effect needs treatment. In Moore's review, dry mouth was experienced by 25% of patients, which is a significant problem for this age group of 55 years and over. These problems do limit the use of oral opioids–most patients who require medication for non-cancer pa