Pain
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The objective of this paper is to better understand the relationship of pain and mood in patients with fibromyalgia and comorbid major depressive disorder (MDD). Pooled data from 4 double-blind, placebo-controlled, randomized trials of duloxetine hydrochloride 60-120mg/day in patients with fibromyalgia were included (N=1332). Of these, 350 (26% [147 placebo, 203 duloxetine]) had comorbid MDD (per Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition Text Revision criteria) and were included in these analyses. ⋯ Results indicated that 69% of improvement in pain was a direct effect of treatment, with improvement in mood accounting for 31% of pain response. In conclusion, consistent with our hypothesis, duloxetine produced a substantial direct effect on pain improvement and change in mood exerted a modest indirect effect on pain improvements in patients with fibromyalgia and MDD. Hence, both direct and indirect analgesic and antidepressant properties appear to be relevant for the treatment of these comorbid patients with duloxetine.
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Randomized Controlled Trial Multicenter Study
Spinal cord stimulation for the treatment of refractory angina pectoris: a multicenter randomized single-blind study (the SCS-ITA trial).
Spinal cord stimulation (SCS) is believed to be effective in treating refractory angina. The need for SCS-related chest paresthesia, however, has hitherto made impossible placebo-controlled trials. Subliminal (non paresthesic) SCS, however, might be also effective on anginal pain. ⋯ At 3months, a significant difference between groups PS and SS was observed in angina attacks (p=0.002), but not in other variables. Thus, in this study, paresthesic, but not subliminal SCS was superior to sham SCS in improving clinical status in refractory angina patients. The lack of significant differences between PS and SS groups in this small study suggests that a possible role for subliminal SCS in individual patients deserves to be assessed in larger trials with appropriate statistical power.
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In different fields of neuroscience research, illusions have successfully been used to unravel underlying mechanisms of stimulus processing. One such illusion existing for the field of pain research is the so-called thermal grill illusion. Here, painful sensations are elicited by interlacing warm and cold bars, with stimulus intensities (temperatures) of these bars being below the respective heat pain or cold pain thresholds. ⋯ Induction of sad, but not neutral mood states, resulted in higher pain and unpleasantness ratings of the painful illusion. These findings might be of importance for the understanding of pain processing in healthy volunteers, but putatively even more so in patients with major depressive disorder. Moreover, our results might indicate that central nervous structures involved in the affective domain or cognitive domain of pain processing might be involved in the perception of the illusion.
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This is a revision of guidelines, originally published in 2004, for the assessment of patients with neuropathic pain. Neuropathic pain is defined as pain arising as a direct consequence of a lesion or disease affecting the somatosensory system either at peripheral or central level. Screening questionnaires are suitable for identifying potential patients with neuropathic pain, but further validation of them is needed for epidemiological purposes. ⋯ Skin biopsy to measure the intraepidermal nerve fiber density should be performed in patients with clinical signs of small fiber dysfunction. The intensity of pain and treatment effect (both in clinic and trials) should be assessed with numerical rating scale or visual analog scale. For future neuropathic pain trials, pain relief scales, patient and clinician global impression of change, the proportion of responders (50% and 30% pain relief), validated neuropathic pain quality measures and assessment of sleep, mood, functional capacity and quality of life are recommended.
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The effects of depression and smoking on pain severity and opioid use in patients with chronic pain.
Depression and smoking are common comorbid conditions among adults with chronic pain. The aim of this study was to determine the independent effects of depression on clinical pain and opioid use among patients with chronic pain according to smoking status. A retrospective design was used to assess baseline levels of depression, clinical pain, opioid dose (calculated as morphine equivalents), and smoking status in a consecutive series of patients admitted to a 3-week outpatient pain treatment program from September 2003 through February 2007. ⋯ However, status as a current smoker was independently associated with greater opioid use (by 27mg/d), independent of depression scores. The relationship between depression, smoking status, opioid use, and chronic pain is complex, and both depression and smoking status may be potentially important considerations in the treatment of patients with chronic pain who utilize opioids. This study found that pain severity was associated with greater depression but not smoking; however, smoking was associated with greater opioid use, independent of depression.