Co-Planar Stereotaxic Atlas of the Human Brain—3-Dimensional Proportional System: An Approach to Cerebral Imaging, J. Talairach, P. Tournoux. Georg Thieme Verlag, New York (1988), 122 pp., 130 figs. DM 268

Importance Primary care clinicians find managing chronic pain challenging. Evidence of long-term efficacy of opioids for chronic pain is limited. Opioid use is associated with serious risks, including opioid use disorder and overdose. Objective To provide recommendations about opioid prescribing for primary care clinicians treating adult patients with chronic pain outside of active cancer treatment, palliative care, and end-of-life care. Process The Centers for Disease Control and Prevention (CDC) updated a 2014 systematic review on effectiveness and risks of opioids and conducted a supplemental review on benefits and harms, values and preferences, and costs. CDC used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) framework to assess evidence type and determine the recommendation category. Evidence Synthesis Evidence consisted of observational studies or randomized clinical trials with notable limitations, characterized as low quality using GRADE methodology. Meta-analysis was not attempted due to the limited number of studies, variability in study designs and clinical heterogeneity, and methodological shortcomings of studies. No study evaluated long-term (≥1 year) benefit of opioids for chronic pain. Opioids were associated with increased risks, including opioid use disorder, overdose, and death, with dose-dependent effects. Recommendations There are 12 recommendations. Of primary importance, nonopioid therapy is preferred for treatment of chronic pain. Opioids should be used only when benefits for pain and function are expected to outweigh risks. Before starting opioids, clinicians should establish treatment goals with patients and consider how opioids will be discontinued if benefits do not outweigh risks. When opioids are used, clinicians should prescribe the lowest effective dosage, carefully reassess benefits and risks when considering increasing dosage to 50 morphine milligram equivalents or more per day, and avoid concurrent opioids and benzodiazepines whenever possible. Clinicians should evaluate benefits and harms of continued opioid therapy with patients every 3 months or more frequently and review prescription drug monitoring program data, when available, for high-risk combinations or dosages. For patients with opioid use disorder, clinicians should offer or arrange evidence-based treatment, such as medication-assisted treatment with buprenorphine or methadone. Conclusions and Relevance The guideline is intended to improve communication about benefits and risks of opioids for chronic pain, improve safety and effectiveness of pain treatment, and reduce risks associated with long-term opioid therapy.

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CDC Guideline for Prescribing Opioids for Chronic Pain—United States, 2016

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CDC guideline for prescribing opioids for chronic pain

The mammalian ionotropic glutamate receptor family encodes 18 gene products that coassemble to form ligand-gated ion channels containing an agonist recognition site, a transmembrane ion permeation pathway, and gating elements that couple agonist-induced conformational changes to the opening or closing of the permeation pore. Glutamate receptors mediate fast excitatory synaptic transmission in the central nervous system and are localized on neuronal and non-neuronal cells. These receptors regulate a broad spectrum of processes in the brain, spinal cord, retina, and peripheral nervous system. Glutamate receptors are postulated to play important roles in numerous neurological diseases and have attracted intense scrutiny. The description of glutamate receptor structure, including its transmembrane elements, reveals a complex assembly of multiple semiautonomous extracellular domains linked to a pore-forming element with striking resemblance to an inverted potassium channel. In this review we discuss International Union of Basic and Clinical Pharmacology glutamate receptor nomenclature, structure, assembly, accessory subunits, interacting proteins, gene expression and translation, post-translational modifications, agonist and antagonist pharmacology, allosteric modulation, mechanisms of gating and permeation, roles in normal physiological function, as well as the potential therapeutic use of pharmacological agents acting at glutamate receptors.

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Glutamate Receptor Ion Channels: Structure, Regulation, and Function

https://onlinelibrary.wiley.com/doi/epdf/10.1002/acr.20543

Measures of Adult Pain: Visual Analog Scale for Pain (VAS Pain), Numeric Rating Scale for Pain (NRS Pain), McGill Pain Questionnaire (MPQ), Short-Form McGill Pain Questionnaire (SF-MPQ), Chronic Pain Grade Scale (CPGS), Short Form-36 Bodily Pain Scale (SF-36 BPS), and Measure of Intermittent and Constant Osteoarthritis Pain (ICOAP)

Drug Discovery for Neuropathic Pain

Purpose We conducted a feasibility 2×2 factorial trial comparing N-methyl-D-aspartate (NMDA) antagonists (intravenous ketamine and oral memantine) versus placebo and intravenous steroids versus placebo, in patients having elective video-assisted thoracic surgery lobectomies, at St. Joseph's Hamilton, Canada, and Cleveland Clinic, Cleveland, USA. Our feasibility objectives were: 1) recruitment rate/week; 2) recruitment of ≥90% of eligible patients; and 3) >90% follow-up. Secondary objectives were incidence and intensity of persistent post-surgical pain (PPSP) and other clinical and safety outcomes. Methods Using computerized randomization, patients were allocated to one of four groups: NMDA active with steroid placebo; NMDA placebo with steroid active; both NMDA and steroid active; both NMDA and steroid placebo. Patients, health providers, and data analysts were blinded to allocation. Patients were followed for 3 months after randomization. Results The trial was initiated in May 2017 at Hamilton and, after subsequent regulatory and ethics approval, in April 2018 at Cleveland. The trial had to be stopped after only 1 month of recruitment in Cleveland because the packaged study medications (memantine) expired and we were unable to procure the dosage required. Among 41 eligible patients, 27 (66%) were randomized. The recruitment rate/week was 0.63, 95% confidence interval (CI): 0.47-0.79 in Hamilton; and 1, 95% CI: 0.83-1.17 in Cleveland. Follow-up was complete for all 24 patients (100%) in Hamilton, and 3 of 4 patients in Cleveland. In total, only 4 patients (15%), and 2 patients (7%) had persistent pain at rest and with movement, respectively. There were no significant differences between groups for other outcomes. Conclusion The trial had to be stopped prematurely due to non-availability of study medications. Trial feasibility objectives of recruiting 90% of eligible patients and recruiting at least one patient/week per site were not met. Consideration for protocol changes will be necessary for the full trial. Trial registration NCT02950233.

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N-Methyl-D-Aspartate Antagonists and Steroids for the Prevention of Persisting Post-Surgical Pain After Thoracoscopic Surgeries: A Randomized Controlled, Factorial Design, International, Multicenter Pilot Trial.

The Emergency Drug Release Program: regulatory aspects of new drug access in Canada

Background: Pain is one of the most common, feared, and unpleasant symptoms associated with surgery. However, there is a clear gap in patient care after surgical patients are discharged from hospital, resulting in poorly controlled postoperative pain. Inadequate pain management after discharge can have detrimental effects on quality of life and lead to the development of chronic postsurgical pain. The severity of postoperative pain before discharge is well described, but less emphasis has been placed on assessing pain at home after hospital discharge.
Objective: The objective of this review is to summarize the prevalence of moderate-to-severe postoperative pain within the first 1 to 14 days after hospital discharge.
Methods: A detailed search of epidemiological studies investigating postoperative pain will be conducted on MEDLINE and EMBASE from their inception until the date the searches are run. The primary outcome will be the proportion of patients reporting moderate-to-severe postoperative pain at rest and with movement within the first 1 to 14 days after hospital discharge. The secondary outcomes will include a comparison of postoperative pain after discharge between patients who underwent ambulatory and inpatient surgery, and adverse outcomes attributable to poor pain control after hospital discharge (eg, readmission to hospital, emergency room or other unplanned medical visits, or a decrease in quality of life).
Results: The protocol has been registered in PROSPERO (registration number CRD42020194346). The search strategies for MEDLINE and EMBASE have been completed. The final results are expected to be published in May 2021.
Conclusions: This systematic review is expected to synthesize evidence describing the prevalence of postoperative pain after hospital discharge. Available epidemiological evidence may help inform the magnitude of the problem of postoperative pain at home after hospital discharge.
Trial Registration: PROSPERO International Prospective Register of Systematic Reviews CRD42020194346; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=194346

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Ian Gilron

Papers

Drug Discovery for Neuropathic Pain

N-Methyl-D-Aspartate Antagonists and Steroids for the Prevention of Persisting Post-Surgical Pain After Thoracoscopic Surgeries: A Randomized Controlled, Factorial Design, International, Multicenter Pilot Trial.

The Emergency Drug Release Program: regulatory aspects of new drug access in Canada

Prevalence of Postoperative Pain Following Hospital Discharge: Protocol for a Systematic Review.

Interventions for the prevention of acute postoperative pain in adults following brain surgery