Pain
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There has been a tension between the needs of regulators and industry to demonstrate that interventions are effective and safe, and the needs of professionals to understand how well interventions will work for their patients, and patients to understand what might work for them as individuals. The custom has been to focus on statistical outcomes based on average results, but in-depth analysis based on outcomes obtained by individual patients demonstrates that few are average. ⋯ This changes how benefit and risk are seen; nonresponders should stop treatments that don't work and not, therefore, be exposed to risks, while responders have very large benefits to offset against rare but potentially serious harm. This alternative view, patient-centred and practice-orientated, has major implications for clinical practice, how and why we do clinical trials and how they are designed, how health economic evaluations are done, for decisions made by regulatory and other bodies, and for the theory and practice of evidence-based medicine.
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Randomized Controlled Trial Multicenter Study
Duloxetine and pregabalin: High-dose monotherapy or their combination? The "COMBO-DN study" - a multinational, randomized, double-blind, parallel-group study in patients with diabetic peripheral neuropathic pain.
This multicentre, double-blind, parallel-group study in diabetic peripheral neuropathic pain addressed whether, in patients not responding to standard doses of duloxetine or pregabalin, combining both medications is superior to increasing each drug to its maximum recommended dose. For initial 8-week therapy, either 60 mg/day duloxetine (groups 1, 2) or 300 mg/day pregabalin (groups 3, 4) was given. Thereafter, in the 8-week combination/high-dose therapy period, only nonresponders received 120 mg/day duloxetine (group 1), a combination of 60 mg/day duloxetine and 300 mg/day pregabalin (groups 2, 3), or 600 mg/day pregabalin (group 4). ⋯ In exploratory analyses of the initial 8-week therapy uncorrected for multiple comparisons, 60 mg/day duloxetine was found superior to 300 mg/day pregabalin (P < 0.001). Both drugs and their combination were well tolerated. Although not significantly superior to high-dose monotherapy, combination therapy was considered to be effective, safe, and well tolerated.
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The pain matrix is conceptualised here as a fluid system composed of several interacting networks. A nociceptive matrix receiving spinothalamic projections (mainly posterior operculoinsular areas) ensures the bodily specificity of pain and is the only one whose destruction entails selective pain deficits. Transition from cortical nociception to conscious pain relies on a second-order network, including posterior parietal, prefrontal and anterior insular areas. ⋯ Neuropathic allodynia has been associated with enhancement of ipsilateral over contralateral insular activation and lack of reactivity in orbitofrontal/perigenual areas. Although lack of response of perigenual cortices may be an epiphenomenon of chronic pain, the enhancement of ipsilateral activity may reflect disinhibition of ipsilateral spinothalamic pathways due to depression of their contralateral counterpart. This in turn may bias perceptual networks and contribute to the subjective painful experience.
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Randomized Controlled Trial Comparative Study
Comparison of cooling and EMLA to reduce the burning pain during capsaicin 8% patch application: A randomized, double-blind, placebo-controlled study.
Topical capsaicin 8% was developed for the treatment of peripheral neuropathic pain. The pain reduction is associated with a reversible reduction of epidermal nerve fiber density (ENFD). During its application, topical capsaicin 8% provokes distinct pain. ⋯ At all application sites, ENFD was significantly reduced by 8.0 ± 2.8 (ENF/mm ± SD, P < .0001), that is, 70%, with no significant differences between the sites with the different experimental conditions. In conclusion, cooling the skin to 20°C reliably prevents the pain from capsaicin 8% patch application, whereas EMLA does not. ENFD reduction is not inhibited by cooling.