The journal of pain : official journal of the American Pain Society
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Comparative Study
Memory for pain? A comparison of nonexperiential estimates and patients' reports of the quality and intensity of postoperative pain.
Prior research has questioned the extent to which postoperative retrospective ratings of acute pain actually reflect memory of that pain. To investigate this issue, pain ratings provided by patients who had undergone vascular surgery were compared with estimates of this pain provided by 2 groups of healthy, nonpatient participants with no personal experience of the surgery. Patient participants rated postoperative pain while actually experiencing it and again 4 to 6 weeks after surgery. Nonpatient groups read either a comprehensive information leaflet describing postoperative pain after vascular surgery, or a short general information leaflet about the surgery and provided 2 estimates of the likely nature of the pain, 4 to 6 weeks apart. Compared with patients, both nonpatient groups overestimated pain severity, and nonpatients provided with the comprehensive information leaflet were less consistent in their estimates compared with the other 2 groups. However, qualitative descriptions of the pain provided by the 3 groups shared many similarities. Our findings highlight limitations of inferring pain memory accuracy by comparing ratings given while in pain with those provided retrospectively and demonstrate the need to consider the phenomenological awareness accompanying recollections of prior pain events to advance our understanding of memory for pain. ⋯ The observed similarities between pain ratings made by individuals who have experienced a particular pain and estimates made by those without personal experience question whether retrospective pain ratings can be assumed to reflect memory of that pain. The need to adopt new approaches to assess memory for pain is highlighted.
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The agonist-antagonist kappa-opioid nalbuphine administered for postoperative pain produces greater analgesia in females than in males. In fact, males administered nalbuphine (5 mg) experience pain greater than those receiving placebo, suggesting the existence of an anti-analgesic effect. These sexually dimorphic effects on postoperative pain can be eliminated by coadministration of a fixed ratio of the prototypical opioid receptor antagonist naloxone with nalbuphine, implying a role for opioid receptors in the anti-analgesic as well as analgesic effects of nalbuphine. In the present study, we further evaluated the role of opioid receptors in the sex-specific effects on pain produced by nalbuphine by coadministering a dose of morphine low enough that it does not produce analgesia. After extraction of bony impacted third molar teeth, nalbuphine (5 mg) was administered alone or in combination with either of 2 low doses of morphine (2 mg or 4 mg). Both doses of morphine reversed nalbuphine-induced anti-analgesia in males, but only the lower dose (2 mg) reached statistical significance. Neither dose affected nalbuphine-induced analgesia in females, and when administered alone in either males or females, morphine (2 mg) had no analgesic effect. Though not observed in females, the effect of morphine in males argues that, like naloxone, low-dose morphine may act as an anti-analgesia opioid receptor antagonist. ⋯ Previously, we reported that the nalbuphine produces both analgesic and anti-analgesic effects and that the opioid antagonist naloxone can enhance nalbuphine analgesia by selectively antagonizing the anti-analgesic effect. Here we show that morphine, given in a subanalgesic dose, reverses nalbuphine-induced anti-analgesia in males, perhaps by a similar mechanism.
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The original Screener and Opioid Assessment for Patients with Pain (SOAPP) is a conceptually derived self-report questionnaire designed to predict aberrant medication-related behaviors among chronic pain patients considered for long-term opioid therapy. The purpose of this study was to develop and validate an empirically derived version of the SOAPP (SOAPP-R) that addresses some limitations of the original SOAPP. In successive steps, items were reduced from an initial pool of 142 to a 97-item beta version. The beta version was administered to 283 chronic pain patients receiving long-term opioid therapy. Items were evaluated based on data collected at follow-up, including correlation with the Aberrant Drug Behavior Index (ADBI), derived from interview data, physician ratings, and urine toxicology screens. Twenty-four items were retained and comprise the final SOAPP-R. Coefficient alpha was .88, and receiver operating characteristics curve analysis yielded an area under the curve of .81 (P < .001). A cutoff score of 18 showed adequate sensitivity (.81) and specificity (.68). The obtained psychometrics, along with the use of a predictive criterion that goes beyond self-report, suggest that the SOAPP-R is an improvement over the original version in screening risk potential for aberrant medication-related behavior among persons with chronic pain. ⋯ There is a need for a screener for abuse risk in patients prescribed opioids for pain. This study presents a revised version of the SOAPP-R that is empirically derived with good reliability and validity but is less susceptible to overt deception than the original SOAPP version 1.