Misconceptions and controversies regarding the use of opioids in cancer pain.

The WHO has created a Cancer Pain Relief Programme and developed guidelines for the treatment of cancer pain. Implementation of the analgesic guidelines, assurance of drug availability (specifically opioids), education of healthcare professionals, and designating cancer pain as a priority for all national cancer control programmes are the major goals. Recent studies of medical students, physicians, nurses and state medical boards demonstrate a significant lack of knowledge with regard to the theoretical and practical understanding of the use of analgesic drugs, particularly opioids, in the management of cancer pain. Communication between physicians and patients about pain symptoms has also been shown to be problematic. Limited availability of opioids, their excessive regulation, and the lack of use of alternatives to systemic analgesics also prevent adequate management. Although analgesic drug therapy is the mainstay of treatment, opioid use remains a controversial issue. Some of the controversies include their role in the management of neuropathic pain, which has been suggested to be 'opioid-resistant', as well as the choice of opioid drug. A third controversy is the route of administration. The impetus for the development of novel routes has come from the goals of maximising analgesia, minimising side effects, and providing convenient dosing schedules for patients who require parenteral administration. Other important controversial issues are the development of tolerance and the relationship of pain management to patient requests for physician-assisted suicide and euthanasia.