Risk-benefit assessment of opioids in chronic noncancer pain

Opioids have been accepted as appropriate treatment for acute and cancer pa in, but their role in the management of chronic nonmalignant pain is the su bject of much debate, mainly due to concerns about waning efficacy, the pot ential for neuropsychological impairment and the development of drug addict ion. Controlled clinical trials demonstrated that opioids may be effective in bo th nociceptive and neuropathic noncancer pain, although the former responde d more consistently than the latter. Gastrointestinal and CNS adverse effec ts were frequent in most studies. Observational studies have generated contradictory findings regarding effic acy and safety as well as the risk of drug addiction in patients with chron ic noncancer pain receiving long term opioid therapy. However, they suggest that opioids may be effective in individual cases, whichever the pathophys iological mechanism of pain. Taken together, the available data indicate that the outcomes associated wi th opioid therapy vary markedly across patients experiencing chronic nonmal ignant pain. The main consensus is that a subset of these patients may gain substantial benefit from opioid analgesics without requiring rapidly escal ating doses or developing intolerable adverse effects or drug addiction. Pr escribing guidelines have been developed to assist practitioners in selecti ng the appropriate patients and ensuring an acceptable risk : benefit ratio of opioid therapy. Finally, it must be emphasised that chronic pain is a c omplex entity wherein analgesics, including opioids, are only part of the t reatment.