The journal of pain : official journal of the American Pain Society
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This report describes a study of how patients view their pain medications. Two hundred and twenty patients with chronic pain completed a set of 78 items regarding beliefs and concerns about pain medication, a brief measure of medication use, and measures of depression and disability. Item and scale analyses resulted in a 47-item measure, the Pain Medication Attitude Questionnaire (PMAQ), that assesses 7 areas of patient concern: addiction, perceived need, unfavorable scrutiny by others, adverse side effects, tolerance, mistrust in the prescribing doctor, and withdrawal. These seven scales had excellent internal consistency and predictable relations with the measures of medication use, depression, and disability supporting their validity. Correlation analyses highlighted relatively strong associations between concerns about medication and measures of emotional distress and disability, suggesting that these concerns may add significantly to the burden of chronic pain. We suggest that concerns about medication use warrant further study and may deserve clinical attention. ⋯ All medication use by chronic pain sufferers is essentially a pattern of patient behavior over time. As such, it appears to be multiply-determined, by beliefs, emotions, bodily sensations, and the social, cultural, and personal learning history that give these experiences their meaning and functions.
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Spinal glial activation and consequent interleukin-1 (IL-1) release are implicated in pain facilitation induced by inflammation/damage to skin and peripheral nerves. It is unclear whether pain facilitation induced at deep tissue sites also depends on these. We investigated whether spinal IL-1 and/or glial activation mediates bilateral allodynia induced by repeated unilateral intramuscular injections of acidic saline to rats. Given the prominent role of spinal IL-1 in various bilateral pain models, we predicted that intrathecal IL-1 receptor antagonist (IL-1ra) would suppress bilateral allodynia in this model as well. Surprisingly, neither single nor repeated intrathecal injections of IL-1ra affected allodynia, measured by the von Frey test, induced by prior intramuscular acidic saline compared with vehicle-injected controls. In addition, we tested the effect of 2 additional intrathecal manipulations that are broadly efficacious in suppressing glially mediated pain facilitation: (1) a glial metabolic inhibitor (fluorocitrate) and (2) the anti-inflammatory cytokine, interleukin-10 (IL-10). Like IL-1ra, fluorocitrate and IL-10 each failed to reverse allodynia. Finally, we observed no significant activation of glial cells, as assessed by immunohistochemistry of glial activation markers, in the lumbar spinal cord in response to intramuscular acidic saline. Taken together, the present data suggest that acidic saline-induced bilateral allodynia is created independently of glial activation. ⋯ From converging lines of evidence, the current studies suggest that persistent bilateral allodynia induced by repeated intramuscular acidic saline is not mediated by spinal IL-1 and/or spinal glial activation. As such, this might represent the first evidence for pain facilitation occurring in the absence of glial involvement.
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Randomized Controlled Trial Multicenter Study
A series of three sequential, randomized, controlled studies of repeated treatments with botulinum toxin type A for migraine prophylaxis.
We examined the effects of multiple treatments with low doses of botulinum toxin type A (BoNTA; BOTOX(R), Allergan Inc., Irvine, CA) versus placebo for prophylaxis of episodic migraine. This was a series of 3 sequential, randomized, controlled studies of 418 patients with a history of 4 to 8 moderate to severe migraines per month. In study I, patients were randomized to treatment with placebo or BoNTA (7.5 U, 25 U, or 50 U) in predetermined fixed injection sites on the front and sides of the head only. In study II, patients continued to receive, or were randomized to, 2 consecutive treatments with 25 U or 50 U. In study III, patients were randomized to placebo or continuation of 25 U or 50 U. Injection cycles were each 4 months long. BoNTA and placebo produced comparable decreases from baseline in the frequency of migraines at each time point examined (P >or= .201). No consistent, statistically significant differences were observed for any efficacy variable. Adverse events were similar among the groups within each study. In these exploratory studies of episodic migraine patients, repeated injections of low doses of BoNTA into fixed frontal, temporal, and glabellar sites were not more effective than placebo. BoNTA was safe and well tolerated. ⋯ Beneficial effects of BoNTA in the treatment of migraine have been reported, but positive results are not universal, possibly because the optimal patient population and regimen are not yet definitively established. This study explores the effects of multiple injections of low BoNTA doses into fixed sites for episodic migraine.
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Multicenter Study
Catastrophizing and pain-contingent rest predict patient adjustment in men with chronic prostatitis/chronic pelvic pain syndrome.
Cognitive/behavioral and environmental variables are significant predictors of patient adjustment in chronic pain. Using a biopsychosocial template and selecting several pain-relevant constructs from physical, cognitive/behavioral, and environmental predictors, outcomes of pain and disability in chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) were explored. Men (n = 253) from a North American multi-institutional NIH-funded Chronic Prostatitis Cohort Study in 6 US and 1 Canadian centers participated in a survey examining pain and disability. Measures included demographics, urinary symptoms, depression, pain, disability, catastrophizing, control over pain, pain-contingent rest, social support, and solicitous responses from a significant other. Regressions showed that urinary symptoms (beta = .20), depression (beta = .24), and helplessness catastrophizing (beta = .29) predicted overall pain. Further, affective pain was predicted by depression (beta = .39) and helplessness catastrophizing (beta = .44), whereas sensory pain was predicted by urinary symptoms (beta = .25) and helplessness catastrophizing (beta = .37). With regard to disability, urinary symptoms (beta = .17), pain (beta = .21), and pain-contingent rest (beta = .33) were the predictors. These results suggest cognitive/behavioral variables (ie, catastrophizing, pain-contingent rest) may have significant impact on patient adjustment in CP/CPPS. Findings support the need for greater research of such pain-related variables in CP/CPPS. ⋯ This article explores predictors of patient adjustment in chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). Cognitive/behavioral variables of catastrophizing and pain-contingent rest respectively predicted greater pain and disability. Catastrophic helplessness was a prominent pain predictor. These findings inform clinicians and researchers on several new variables in CP/CPPS outcomes and suggest future research.
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Prescription of opioids for nonmalignant musculoskeletal pain has increased substantially in recent years, but there is little information on the incidence of, or factors associated with, such prescription for work-related back pain. In a prospective cohort study (N = 1,067), we examined associations between worker sociodemographic and other characteristics and opioid prescription within six weeks of the first medical visit for workers' compensation claims for work loss due to back injury. We examined administrative, pharmacy, and worker-reported data. In bivariate logistic regression models, Hispanics were less likely than non-Hispanic whites to receive opioid prescriptions, and very high body mass index, daily tobacco use, greater pain and physical disability, pain radiating below the knee, injury severity categorizations (from medical records) of major sprain and radiculopathy, and worse mental health were associated with opioid prescription. Adjusting for demographics, pain intensity, and physical disability, opiate prescription was significantly associated with daily tobacco use, pain radiating below the knee, and injury severity categories (major sprain and radiculopathy). Knowledge of worker characteristics associated with early opioid prescription may be useful in future studies of the role of early pain treatment in influencing subsequent course of pain and disability among workers with back injuries. ⋯ Little is known about patient characteristics that may influence physicians' decisions concerning prescription of opioids for acute back pain. Not surprisingly, workers with more severe back injuries are more likely to be prescribed opioids, but reasons for prescription disparities based on ethnicity and tobacco use warrant further study.