The Clinical journal of pain
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Comparative Study
Abuse and addiction issues in medically ill patients with pain: attempts at clarification of terms and empirical study.
The assessment of addiction-related outcomes is crucial to the management of chronic pain with opioid drugs in all patients. Pain management for patients who have concomitant drug abuse or addiction issues is a particularly complex task involving a need for a common nomenclature as well as empirically derived data to support management strategies during treatment regimens. Complicating the issue is the notion of pseudoaddiction, which is an abuse of medications driven by unrelieved pain that appears on the surface to be very similar to the behavior patterns of addicts. ⋯ What is ultimately needed is a broad-based spectrum of research that highlights the epidemiology of drug-taking behaviors for different medical illnesses ranging from cancer to back pain. This article focuses on some of these issues as well as recounting attempts by our research group to address these issues systematically in hopes of shedding light on the nature of abuse issues in the medically ill. Although advances have been made, there is a definite need for large-scale studies that address the issues of identification and treatment of aberrant behavior in medically ill patients in the effort to provide the best possible outcomes for patients with chronic pain.
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Review
Assessment of efficacy of long-term opioid therapy in pain patients with substance abuse potential.
Clinical experience supports the notion that opioids can be used successfully to treat many chronic pain conditions. Unfortunately, few controlled trials have assessed which individuals benefit from long-term opioid therapy, and there is concern about the use of long-term opioid therapy in individuals with a substance-abuse history. This article contains three sections relevant to the assessment of individuals with chronic pain and a substance-abuse history who are receiving long-term opioid therapy. ⋯ The third reviews areas critical in assessing treatment efficacy and substance abuse in patients with chronic pain, both in terms of documentation of past behaviors and as a measure of outcome of opioid therapy. Potential guidelines for use of opioids in patients with chronic noncancer pain are outlined. Finally, questions are posed for future investigations of the efficacy of opioid therapy for patients with chronic pain and a substance-abuse history.
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The pharmacological effects of the opioid analgesics are derived from their complex interactions with three opioid receptor types (mu, delta, and kappa; morphine is an agonist at the mu opioid receptor). These receptors are found in the periphery, at presynaptic and postsynaptic sites in the spinal cord dorsal horn, and in the brain stem, thalamus, and cortex, in what constitutes the ascending pain transmission system, as well as structures that comprise a descending inhibitory system that modulates pain at the level of the spinal cord. ⋯ A number of opioids are available for clinical use, including morphine, hydromorphone, levorphanol, oxymorphone, methadone, meperidine, oxycodone, and fentanyl, and their advantages and disadvantages for the management of pain are discussed. An understanding of the pharmacokinetic properties, as well as issues related to opioid rotation, tolerance, dependence, and addiction are essential aspects of the clinical pharmacology of opioids for pain.
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Comparative Study
Effects of intermediate- and long-term use of opioids on cognition in patients with chronic pain.
The authors review research on the intermediate- and long-term effects of taking opioid medication on cognitive functioning in patients with chronic cancer and noncancer pain. Opioids seem to be more likely to worsen cognitive performance during the first few days of use and during the first few hours after a given dose, particularly on timed performance in psychomotor tasks. ⋯ Relatively few differences have been found when cognitive performance in these patients is compared with their performance before taking opioids, or with the performance of a comparable pain population not taking opioids. Major unresolved questions remain regarding such important issues as effects of different types of opioids, dose effects, interactions with other medications, and subject variables.
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Review Comparative Study
Complex regional pain syndrome type I: use of the International Association for the Study of Pain diagnostic criteria defined in 1994.
The objective was to assess the reported use in recent publications of the diagnostic criteria for complex regional pain syndrome type I (CRPS I) proposed by the International Association for the Study of Pain (IASP) in 1994. ⋯ If the diagnostic criteria for CRPS I are not used uniformly, the populations in clinical studies may not be uniform either. Whether different authors are describing the same syndrome and whether their findings can be compared is open to question. On the basis of the results of this study, it is concluded that the IASP criteria for CRPS I are poorly used in clinical studies.