The journal of pain : official journal of the American Pain Society
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Clinical Trial Controlled Clinical Trial
Morphine responses and experimental pain: sex differences in side effects and cardiovascular responses but not analgesia.
Sex differences in analgesic responses to mu opioid agonists have been reported, although the direction of these differences varies across studies. To further characterize sex differences in responses to mu opioids, the analgesic effects of intravenous morphine (0.08 mg/kg) were determined in healthy women (n = 61) and men (n = 39) by using 3 experimental pain models, heat pain, pressure pain, and ischemic pain. Each pain procedure was conducted before and after double-blind administration of both morphine and saline, which occurred on separate days in counterbalanced order. Although morphine produced significant analgesic effects for all pain stimuli, no significant sex differences in morphine analgesia emerged. However, morphine attenuated cardiovascular reactivity to the ischemic pain task in men but not women, and women reported significantly more drug-related adverse effects than men. These findings are in contrast with some recent clinical and experimental results suggesting more robust analgesic response to mu opioids among women compared to men, although the data indicate that sex differences in non-analgesic effects of morphine were present. These results suggest that sex differences in responses to morphine might depend on the pain model and/or drug dose as well as the specific end point assessed. ⋯ This study examines morphine responses in women and men by using laboratory pain measures. The results indicate no sex differences in analgesia, but women reported greater side effects, and morphine attenuated cardiovascular responses more strongly among men than women. These results add to the literature regarding sex differences in response to opioids.
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Randomized Controlled Trial Clinical Trial
Electronic diary assessment of pain-related variables: is reactivity a problem?
Reactive measures (measures that change the phenomenon assessed) cause problems in interpreting any changes observed. This study examined whether electronic daily diary measures of pain, activity interference, mood, and pain beliefs were reactive in terms of both observable data and patient-reported effects. Patients with chronic temporomandibular disorder pain (N = 71, 86% female) completed electronic diaries 3 times daily for approximately 2 weeks and subsequently reported perceived effects on symptom-related variables. Seventy-three percent of patients reported that the assessment affected their pain, whereas 51%, 45%, and 39% thought that it affected their daily activities, mood, and beliefs, respectively. In contrast, there was little objective evidence of reactivity as observed in the electronic diary ratings; changes over 14 days were small (eg, predicted changes on 0 to 10 scales: positive mood, .1; pain, -.3; perceived control, -.5) and not statistically significant. Subjective reactivity was generally not significantly related to objective reactivity. The data suggest that patients view daily assessment as having positive and negative effects on pain-related variables, but pain-related measures do not show reactive effects. ⋯ Electronic daily diary assessment methods hold the potential to increase knowledge concerning patients' experiences with pain and sequential relations between pain-related variables, but only if the measurement process is nonreactive. This study provides evidence that electronic diary assessment of pain-related variables is nonreactive.
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By elaborating on previous prospective and cross-sectional research, the primary aim of this study was to examine in the general community whether pain catastrophizing predicts the development of chronic pain complaints and other consequences of pain. The following health index values were examined as consequences of pain: specialist consultation, use of pain medication, and absenteeism. It was also examined whether these relationships were moderated by the number of pain problems and by pain intensity. The results demonstrated a generally low level of catastrophizing and a small but significant effect of catastrophizing on the development of chronic pain complaints. With respect to the health index values, no significant effects of catastrophizing were found, nor were the relationships between catastrophizing and chronicity and the health index values moderated by the number of pain problems or by pain intensity. ⋯ Because in the general community the level of catastrophizing is low, its role in the development of future pain problems is probably limited in this type of setting. More practically, the Pain Catastrophizing Scale, used to measure pain catastrophizing, is probably of limited use as a screening instrument in the general community. The disappointing results may indicate that, depending on the specific setting (eg, clinical, outpatient, or community) the role of pain catastrophizing is either more or less prominent.
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Clinical observations suggest that many patients with chronic pain have difficulty forgiving persons they perceive as having unjustly offended them in some way. By using a sample of 61 patients with chronic low back pain, this study sought to determine the reliability and variability of forgiveness assessments in patients and to examine the relationship of forgiveness to pain, anger, and psychological distress. Standardized measures were used to assess patients' current levels of forgiveness, forgiveness self-efficacy, pain, anger, and psychological distress. Results showed that forgiveness-related constructs can be reliably assessed in patients with persistent pain, and that patients vary considerably along dimensions of forgiveness. Furthermore, correlational analyses showed that patients who had higher scores on forgiveness-related variables reported lower levels of pain, anger, and psychological distress. Additional analyses indicated that state anger largely mediated the association between forgiveness and psychological distress, as well as some of the associations between forgiveness and pain. These findings indicate that forgiveness can be reliably assessed in patients with persistent pain, and that a relationship appears to exist between forgiveness and important aspects of living with persistent pain. ⋯ This preliminary study suggests there is a relationship between forgiveness and pain, anger, and psychological distress in patients with chronic low back pain. Patients who report an inability to forgive others might be experiencing higher pain and psychological distress that are mediated by relatively higher levels of state anger.
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Clinical Trial
Assessment of pain quality in chronic neuropathic and nociceptive pain clinical trials with the Neuropathic Pain Scale.
Although a number of measures of pain qualities exist, little research has examined the potential for these measures to identify the unique effects of pain treatments on different pain qualities. We examined the utility of the Neuropathic Pain Scale (NPS) for assessing changes in pain qualities after open label lidocaine patch 5% in 3 samples of patients: patients with peripheral neuropathic pain, low back pain, and osteoarthritis. With one exception ("cold" pain in subjects with low back pain), each of the NPS items showed significant change after open label lidocaine patch. In addition, significantly larger changes were observed for the NPS items reflecting global pain intensity and pain unpleasantness and for items assessing sharp and deep pain than for items assessing cold, sensitive, and itchy pain. The pattern of changes in pain qualities did not differ across the 3 diagnostic groups, but it did differ from the patterns of changes in pain qualities associated with other analgesic treatments. The results support the potential utility of the NPS for assessing the patterns of changes in pain qualities that can be observed after pain treatment. ⋯ Pain clinical trials that include measures of pain qualities, such as the NPS, might identify distinct patterns of treatment effects on those pain qualities. This research might be used to help clinicians target analgesics to match the specific qualities associated with a patient's pain and to better understand the mechanisms of analgesic effects in drug development programs.