Use of opioids to treat chronic, noncancer pain

Use of opioids to treat chronic, noncancer painThe American Medical Association's Council on Scientific Affairs previously addressed barriers to the appropriate management of pain in patients with acute and chronic cancer pain (Report 4, presented at the annual meeting of the AMA, 1995).Authoritative guidelines on these aspects of pain management now exist. 1,2However, the use of controlled substances to treat chronic pain in patients who do not have cancer continues to be at the forefront of regulatory, disciplinary, and clinical practice disputes.A number of critical issues underlie physicians' concerns over the use of opioids in patients with chronic, noncancer pain.These issues include safety and efficacy, the development of tolerance and physical dependence, the potential for drug misuse or addiction, and physicians' fear of regulatory scrutiny and legal sanctions.These issues and the neurobiology of acute and chronic pain are briefly reviewed in this report.Some physicians continue to undertreat pain.Some of this is influenced by the lack of adequate education and training in pain diagnosis and treatment, which contributes to poor management by physicians of chronic pain.Thus, improvements in education must accompany any initiatives designed to eliminate other barriers. METHODSEnglish-language reports of studies on people were selected from a MEDLINE search of the literature from 1966 to June 1999 using the MeSH headings "analgesics, opioid," "pain," and "chronic disease" but excluding "neoplasm."A total of 257 articles were retrieved.Additional articles were identified by reviewing the references cited in these publications.Further information was obtained from the websites of the American Pain Society (www.ampainsoc.org),the American Academy of Pain Medicine (www.painmed.org),the American Academy of Pain Management (www.aapainmanage.org), the American Society of Addiction Medicine (www.asam.org), the Pain and Policy Studies Group (www.medsch.wisc.edu/painpolicy), and from recently published textbooks. NEUROBIOLOGY OF NORMAL AND CHRONIC PAINPain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.The perception of pain is influenced by physiological, psychological, and social factors.Thus, the distinction between pain (as the primary sensory experience arising from a noxious stimulus) and suffering (the human reaction to the sensory experience) is important.The human reaction (suffering) takes on an added dimension in patients who have chronic, noncancer pain.Some of these patients not only have persistent pain but also have overriding affective components and learned responses that can lead to severe psychosocial disability and a pattern of repeated interaction with the healthcare system. Nociceptive painPain is normally evoked by only those stimuli that are sufficiently intense to activate primary afferent A fibers and C-fiber nociceptors.These free nerve endings are located in skin, viscera, muscle, fascia, blood vessels, and joint capsules.There are many varieties of nociceptors, the most important of which are nociceptive afferents and polymodal afferents.