The journal of pain : official journal of the American Pain Society
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The current study examined between- and within-subject variability in pain-related symptoms as predictors of pain and fatigue, and identified patient subgroups on the basis of symptom variability characteristics. Two hundred fifty-six fibromyalgia (FM) patients completed daily diaries up to a period of 154 days and reported on symptoms of pain intensity, pain unpleasantness, fatigue, anxiety, and depressed mood. Measures of health status, quality of life, and somatic symptoms were obtained at baseline, and hierarchical linear modeling and cluster analyses were used. ⋯ Three FM subgroups were revealed: low variability in symptoms (cluster 1), high symptom variability (cluster 2), and a mixed variability group characterized by low fluctuation in pain unpleasantness; moderate pain, fatigue, and depressed mood variability; and high anxiety variability (cluster 3). Cluster 3 exhibited lower social functioning and higher levels of pain, compared with cluster 1. These findings support the dynamic nature of FM pain and suggest the presence of FM subgroups on the basis of variation in mood and pain symptomatology.
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Tapentadol, a Schedule II opioid with a combination of µ-opioid activity and norepinephrine reuptake inhibition, is used for the management of moderate to severe acute and chronic pain. Its dual mechanism of action is thought to reduce opioid-related side effects that can complicate pain management. Since approval, tapentadol has been tracked across multiple outcomes suggesting abuse liability, and a pattern of relatively low, although not absent, abuse liability has been found. ⋯ Event rates of abuse per population-level denominators were significantly lower than all other opioids examined. However, when adjusted for drug availability, event rates of abuse were lower than most Schedule II opioids studied, but were not the lowest. Disentangling these 2 sets of findings further by examining various opioid formulations, such as extended-release and the role of abuse-deterrent formulations, is warranted.
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Review Meta Analysis
Altered Primary Motor Cortex Structure, Organisation and Function in Chronic Pain: a Systematic Review and Meta-Analysis.
Chronic pain can be associated with movement abnormalities. The primary motor cortex (M1) has an essential role in the formulation and execution of movement. A number of changes in M1 function have been reported in studies of people with chronic pain. ⋯ There is conflicting evidence of altered M1 structure, organization, and function for neuropathic and non-neuropathic pain conditions. Meta-analyses provided evidence of increased M1 long-interval intracortical inhibition in chronic pain populations. For most measures, the evidence of M1 changes in chronic pain populations is inconclusive.