Opioid poorly-responsive cancer pain. Part 1: Clinical considerations

Pain that is poorly responsive to opioid analgesics is challenging for phys icians who deal with cancer patients. Numerous factors may influence analge sic response during the course of the illness. These include changing nocic eption associated with disease progression, the appearance of intractable s ide effects, the development of tolerance, the presence of neuropathic pain , the temporal pattern, the effects produced by the production of opioid me tabolites, and many others. These factors influence the delicate balance be tween pain relief and opioid toxicity that must be achieved in cancer patie nts with pain. (C) U.S. Cancer Pain Relief Committee, 2001.