Opioids in chronic non-cancer pain, indications and controversies.

The use of opioid analgesics for long term management of chronic non-cancer pain is now an accepted, although still a controversial medical practice. In some well selected patients with long-lasting or recurrent pain, severe enough to markedly reduce their quality of life, and for whom no other more effective and less risky therapy is available, opioid analgesics may reduce intensity of pain, increase functioning and improve quality of life for prolonged periods. The type of pain and pain history of the patients do not predict reliably the chance of long term success or risk of complications from opioid therapy. However, the outlook for successful long term opioid therapy is better in a patient with a stable psychosocial situation having nociceptive type pain that is markedly relieved by a moderate dose of a long lasting oral or transdermal opioid, than a patient from a complex and unstable psychosocial background having neuropathic type pain that is relieved only partly by a higher dose of a potent opioid. When a patient is managed by a multidisciplinary team, the compliance is better and risk of loss of control and complications are less than when a single doctor is managing the patient. The evidence base for this type of pain management is meagre because the needed randomized controlled trials, which ideally should last for several years, have not been performed. Therefore a number of national and international guidelines are being published, recommending experts' opinion on appropriate use and responsible follow-up of long term treatment with opioids for chronic non-cancer pain.