• Ibuprofen Indicated as a Safer, Equally Effective Alternative to Morphine
    A study published in the Jan. 26 online edition of PEDIATRICS has identified a significant risk for potentially-fatal breathing disruption when morphine is administered at home after surgery to treat pain in children who undergo tonsillectomy with or without adenoidectomy. The findings build on 2 earlier studies conducted by the same organizations reporting that codeine administered for postoperative pain in the same population of children could cause respiratory problems and fatal outcomes for children who are genetically ultra-rapid metabolizers of codeine. Previously, codeine had been the standard treatment for postoperative pain in this population across North America. Following the 2009 recommendations, the US Food and Drug Administration issued a boxed warning and contraindication for pediatric codeine. Morphine, while not officially recommended as an alternative, was frequently prescribed in the belief that children’s response would be more predictable. But the current research, conducted from September 2012 to January 2014, comparing postoperative administration of morphine and acetaminophen to ibuprofen and acetaminophen found substantially higher incidence of blood oxygen desaturation in the morphine group. The study also found that patients in the ibuprofen group had their pain just as effectively controlled. A news story about the study may be read here.    
  • New Diabetic Peripheral Neuropathy Technique for Diagnostic Armamentarium
    A procedure called corneal confocal microscopy (CCM) has been found effective in predicting incipient peripheral neuropathy in patients with type 1 diabetes, according to a study published online this month in Diabetes Care. The technique involves the examination of unmyelinated nerve fibers at high magnification using a laser-scanning corneal confocal microscope. Reduced corneal-nerve fiber length and corneal sensitivity was found to be associated with increased severity of diabetic peripheral neuropathy. Although previous studies have demonstrated the utility of CCM in assessing diabetic neuropathies, the authors state that this is the first to confirm the value of the technique in a predictive capacity. The authors believe that CCM would be a valuable addition to current diagnostic tools, in that it is noninvasive, objective, fast, and reproducible. The current impediment to widespread adoption is the relative scarcity of the imaging equipment and related software. Read the article abstract, with options to access the full report, here.    
  • New Targets for Anxiety Therapy Illuminated
    New research published online December 31 in Neuron posits that a novel form of synaptic plasticity in the anterior cingulate cortex (ACC) may account for anxiety disorders that are often associated with chronic pain. The ACC plays a critical role in chronic pain, and human studies suggest that it might be a hub for anxiety as well. In people with chronic pain, anxiety levels predict the extent of pain, and in imaging studies, people with anxiety show increased activation in the ACC. Previous work by the research team from the University of Toronto found that changes in synaptic strength in the ACC contribute to the emergence of neuropathic pain, through a form of long-term potentiation (LTP), in which AMPA-type glutamate receptors are increased on the postsynaptic membrane. In this study, the team identified a different kind of LTP, generated by increased glutamate release from presynaptic terminals onto pyramidal neurons of the ACC. Their results show that this presynaptic LTP (pre-LTP) is induced after nerve injury or inflammation, and contributes not only to pain, but also to anxiety in a mouse model of neuropathic pain. The findings suggest new potential avenues for therapeutic development that involve preventing pre-LTP buildup in the ACC. Read a news story about the research, with link to the journal article, here.    
  • Methadone Safety: New Study Draws Difference Conclusions
    A new study appearing online this week in JAMA Internal Medicine draws significantly different conclusions on the risks of methadone therapy for pain than had been indicated in previous research. The study reports that outside the hospital, use of methadone to treat pain carries a 46% increased risk of death when compared to the equally effective but more costly alternative, morphine SR (sustained release). The research was conducted at Vanderbilt University Medical Center. A side effect of opioid therapy is repressed respiration, but methadone is apparently unusual in that the analgesic effect is more short-lived than the respiration effect. This, the authors contend, may prompt patients to inadvertently overdose themselves. An additional concern is that methadone is a pro-arrhythmic drug that can trigger lethal ventricular arrhythmias. In 2009, some 4.4 million methadone prescriptions were written in the US for treatment of pain. The study reports that methadone’s higher risk ratio translates to 72 excess deaths per every 10,000 person-years of treatment, compared to morphine SR. The sole previous study comparing these 2 drugs produced a nearly opposite result: 44% decreased mortality with methadone. Read a news story about the study findings here.  
Daniel Carr, MD, FABPM
Pain Research, Education, and Policy Program
Department of Public Health and Community Medicine
Tufts Medical Center
Boston, MA


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