Pain
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Randomized Controlled Trial
Longstanding Complex Regional Pain Syndrome is associated with activating autoantibodies against α-1a adrenoceptors.
Complex regional pain syndrome (CRPS) is a limb-confined posttraumatic pain syndrome with sympathetic features. The cause is unknown, but the results of a randomized crossover trial on low-dose intravenous immunoglobulins (IVIG) treatment point to a possible autoimmune mechanism. We tested purified serum immunoglobulin G (IgG) from patients with longstanding CRPS for evidence of antibodies interacting with autonomic receptors on adult primary cardiomyocytes, comparing with control IgG from healthy and diseased controls, and related the results to the clinical response to treatment with low-dose IVIG. ⋯ To see if there were antibodies to the α-1a receptor, CRPS-IgG was applied to α-1a receptor-transfected rat-1 fibroblast cells. The CRPS serum IgG induced calcium flux, and fluorescence-activated cell sorting showed that there was serum IgG binding to the cells. The results suggest that patients with longstanding CRPS have serum antibodies to α-1a receptors, and that measurement of these antibodies may be useful in the diagnosis and management of the patients.
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The International Headache Society (IHS) provides guidance on the conduct of trials for acute treatment of episodic tension-type headache (TTH), a common disorder with considerable disability. Electronic and other searches identified randomised, double-blind trials of oral drugs treating episodic TTH with moderate or severe pain at baseline, or that tested drugs at first pain onset. The aims were to review methods, quality, and outcomes reported (in particular the IHS-recommended primary efficacy parameter pain-free after 2 hours), and to assess efficacy by meta-analysis. ⋯ No other drugs had evaluable results for these patient-centred outcomes. There was no evidence that any one outcome was better than others. The evidence available for treatment efficacy is small in comparison to the size of the clinical problem.
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Assessment of treatment safety is 1 of the primary goals of clinical trials. Organizations and working groups have created reporting guidelines for adverse events (AEs). Previous research examining AE reporting for pharmacologic clinical trials of analgesics in major pain journals found many reporting inadequacies, suggesting that analgesic trials are not adhering to existing AE reporting guidelines. ⋯ For example, using the ACTTION coding manual, we found that less than one-half of the trials reported specific AE assessment methods; approximately one-third of the trials reported withdrawals due to AEs for each study arm; and about one-fourth of the trials reported all specific AEs. We also examined differences in AE reporting across several trial characteristics, finding that AE reporting was generally more detailed in trials with patients versus those using healthy volunteers undergoing experimentally evoked pain. These results suggest that investigators conducting and reporting NP/NI clinical trials are not adequately describing the assessment and occurrence of AEs.
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Although opioids are frequently prescribed for chronic noncancer pain (CNCP) among Veterans Health Administration (VHA) patients, little has been reported on national opioid prescribing patterns in the VHA. Our objective was to better characterize the dosing and duration of opioid therapy for CNCP in the VHA. We analyzed national VHA administrative and pharmacy data for fiscal years 2009 to 2011. ⋯ Major depression and posttraumatic stress disorder were positively associated with receiving high-volume opioids, but nonopioid substance use disorders were not. Among VHA patients with CNCP, chronic opioid therapy occurs frequently, but for most patients, the average daily dose is modest. Doses and duration of therapy were unchanged from 2009 to 2011.