The journal of pain : official journal of the American Pain Society
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A large proportion of oncology outpatients with bone metastasis report unrelieved pain that significantly interferes with daily functioning and quality of life. However, little is known about the longitudinal pattern of pain intensity and analgesic prescriptions or use. Moreover, despite considerable advantages, the use of sophisticated statistical techniques, such as hierarchical linear modeling (HLM) has not been applied to the study of pain and analgesic outcomes. In a prospective longitudinal study, HLM was used to explore predictors of pain intensity and analgesic prescription and intake at the time of enrollment into the study (intercept) and over the course of 6 weeks (trajectory) in a sample of oncology outpatients with bone metastasis who received standard care for pain. In addition to corroborating known predictors of pain intensity, previously unrecognized variables were found that appear to affect both pain and analgesic outcomes. Importantly, some of the predictors of the trajectories of pain intensity and analgesic use (ie, pain-related distress and Pain Management Index (PMI) scores) are particularly amenable to interventions. Findings from this study suggest that sophisticated statistical modeling can be used in pain research to identify individual risk factors and propose novel targets that can be used to improve pain management in oncology outpatients with bone metastasis. ⋯ Findings from this study suggest that a large amount of inter-individual variability exists in patients' experiences with cancer pain and analgesic use. Future studies need to elucidate the mechanisms that underlie these differences.
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The primary objective of the present study was to examine the relative importance of pain behaviors and judgmental heuristics (eg, gender stereotypes) in observers' inferences about pain intensity and pain genuineness. Participants (n = 90) observed video depictions of chronic pain patients performing a physically challenging task and were asked to make inferences of pain intensity and pain genuineness. Analyses indicated that observers relied on judgmental heuristics and pain behaviors both when making inferences about pain intensity and when making inferences about pain genuineness. Follow-up analyses, however, revealed that judgmental heuristics (eg, gender stereotypes) were significantly less utilized when observers made inferences about pain genuineness than when observers made inferences about pain intensity. When observers made inferences about pain genuineness, analyses indicated that patients' facial pain behaviors became the most important source of information. Taken together, these findings suggest that observers who are asked to make inferences about the genuineness of others' pain are likely to reduce their reliance on judgmental heuristics in favor of more controlled and thoughtful inferential processes characterized by detailed processing of behavioral information, particularly others' facial pain behaviors. ⋯ The current study provides new insights into the processes that are involved in observers' inferences about pain intensity and pain genuineness. These inferences play an important role in treatment decisions and advances in this domain could ultimately contribute to more effective management of the challenges facing patients with pain-related disorders.
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Females are disproportionately affected by irritable bowel syndrome (IBS) with menstrual cycle-dependent fluctuations in abdominal pain suggesting a role for ovarian hormones. IBS patients also exhibit greater activation of brain areas involved in pain affect such as the amygdala, yet the role of supraspinal processes in the effects of ovarian hormones on visceral pain is largely unexplored. The goal of the current study was to determine whether sex steroids act at the level of the amygdala to alter colonic pain sensitivity. Ovariectomized rats received implants on the amygdala of progesterone, estradiol, progesterone combined with estradiol, or cholesterol as a control to examine the involvement of the amygdala in ovarian hormone-mediated changes in visceral sensitivity. Visceral sensitivity was quantified as the number of abdominal contractions, a visceromotor response (VMR), in response to graded pressures of colorectal distension (CRD). Somatic sensitivity was also assessed by measuring the mechanical force required to elicit hindpaw withdrawal. Elevated levels of progesterone and/or estradiol on the amygdala heightened the responsiveness to CRD; in contrast, neither estradiol nor progesterone altered somatic sensation. Furthermore, administration of progesterone or estradiol to areas adjacent to the amygdala did not affect visceral sensitivity. Future studies will address the specific steroid receptors mediating the effects of progesterone and estradiol. ⋯ To our knowledge, this study represents the first description of a specific brain site mediating the effects of ovarian steroids on visceral sensitivity. These data also suggest that an amygdala-dependent mechanism may be responsible, at least in part, for the exacerbation of visceral symptomatology in females.
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Review Comparative Study
Systematic review of the comparative effectiveness of antiepileptic drugs for fibromyalgia.
Fibromyalgia is a difficult-to-treat chronic pain syndrome that affects 2% of the US population. Pregabalin is an antiepileptic recently FDA approved for fibromyalgia treatment. Other antiepileptics have been suggested for treatment. This systematic review examines the relative benefits and harms of antiepileptic drugs in the treatment of fibromyalgia. A literature search was conducted and 8 studies matched criteria (7 studies of pregabalin, 1 of gabapentin). Both drugs reduced mean pain scores more than placebo at a modest rate (pregabalin, 38% to 50%; gabapentin, 51%). In a 6-month trial of pregabalin responders, 32% continued to have response at 6 months, with a mean time to loss of response of 34 days. Compared to placebo, the drugs had similarly high rates of adverse events and withdrawals. Without a head-to-head trial it is not possible to conclude if 1 antiepileptic is more effective or harmful than the other, although limited evidence suggests potential differences. Future studies must directly compare the drugs, include a more broadly defined population, examine long term benefits and harms, and include cointerventions. We conclude that pregabalin and gabapentin are modestly effective for the treatment of fibromyalgia but that their long-term safety and efficacy remain unknown. ⋯ This systematic review evaluates the benefits and harms of using the antiepileptic drugs gabapentin and pregabalin for the treatment of fibromyalgia. Conclusions from this paper can help clinicians to more effectively treat the pain associated with fibromyalgia.