Pain
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Randomized Controlled Trial
Effects of COX inhibition on experimental pain and hyperalgesia during and after remifentanil infusion in humans.
Opioids may enhance pain sensitivity resulting in opioid-induced hyperalgesia (OIH). Activation of spinal cyclooxygenase may play a role in the development of OIH. The aim of this study was to demonstrate remifentanil-induced postinfusion hyperalgesia in an electrical pain and a cold pain model, and to investigate whether COX-2 (parecoxib) or COX-1 (ketorolac) inhibition could prevent hyperalgesia after remifentanil infusion. ⋯ These results demonstrated OIH in both models, and may suggest that COX-2 inhibition is more important than COX-1 inhibition in reducing hyperalgesia. Remifentanil-induced hyperalgesia was demonstrated for both electrically induced pain and cold-pressor pain. Both parecoxib and ketorolac prevented hyperalgesia in the electrical model, parecoxib to a larger extent.
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Chronic pain is a common reason for medical visits, but prevalence estimates vary between studies and have rarely included drug treatment data. This study aimed to examine characteristics of chronic pain and its relation to demographic and health factors, and factors associated with treatment of pain with opioid analgesics. A chronic pain module was added to the 2007 Kansas Behavioral Risk Factor Surveillance System (response rate = 61%). ⋯ S. A. Overall, 45.7% of people who take prescription drugs for chronic pain reported taking opioid analgesics.
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Some expert guidelines recommend time-scheduled opioid dosing over pain-contingent dosing for patients receiving chronic opioid therapy (COT). The premise is that time-scheduled dosing results in more stable opioid blood levels and better pain relief, fewer adverse effects, less reinforcement of pain behaviors, and lower addiction risk. We report results of a survey of 1781 patients receiving COT for chronic noncancer pain, in which 967 reported time-scheduled opioid dosing only and 325 reported pain-contingent opioid dosing only. ⋯ Controlled comparative effectiveness research is needed to assess benefits and risks of time-scheduled opioid dosing relative to pain-contingent opioid dosing among COT patients in ambulatory care. Patients with time-scheduled dosing received higher opioid dosage than patients with pain-contingent dosing. Time-scheduled dosing was associated with greater opioid control concerns than pain-contingent dosing.
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As part of a larger longitudinal study, the current analyses characterize the relationship among pain, psychological distress, and physical function after major lower extremity trauma. Structural equation modeling techniques were utilized to analyze data from a prospective 2-year observational study of 327 patients treated at 8 level I trauma centers. Data were gathered at 3, 6, 12, and 24 months after injury. ⋯ The combination of depressive and anxious distress plays an increasingly important role in mediating the impact of pain on physical function as the recovery from lower extremity trauma progresses from early to later stages. Both pain and psychological distress contribute to reduced function during the first year after a serious injury; however, as recovery proceeds, the role of psychological distress in determining function increases. Longitudinal data on patients with severe leg trauma demonstrates that as recovery proceeds, psychological distress plays an increasingly important role in mediating the impact of pain on function.
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The benefits of transcutaneous electrical nerve stimulation (TENS) for pain relief have not been reliably established, as most systematic reviews find poor methodological quality in many studies. The paradox within the evidence base for TENS is that despite identified sources of bias that may lead to an overestimation of treatment effects, no benefits for TENS can be clearly demonstrated. Conventional assessments of quality assume a single direction of bias, and little work has been undertaken examining other directions of bias. ⋯ We propose criteria for judging directions of bias in future studies of TENS that may be adapted to assess other trials in which implementation fidelity is important, such as other nonpharmacological interventions for pain. Poor implementation fidelity was identified as a significant source of bias in systematic reviews of TENS studies and might explain lack of consistent treatment effects of TENS in pain. Here, criteria for assessing methodology are proposed for use in designing future clinical trials of TENS.