Opioids for the Treatment of Chronic Pain

Sex Differences in Pain Sensitivity in a Dutch Cohort: Cross-Sectional and Web-Based Multidimensional Study

BACKGROUND

Sex is an important factor influencing the development and treatment of chronic pain, but the extent of its influence is still unclear. Other demographic factors as well as nonpharmacological interventions might influence pain sensitivity differently in men and women.

OBJECTIVE

In this study, we aimed to investigate the influence of sex and other demographic, lifestyle, behavioral, clinical, and environmental factors on pain sensitivity in the Dutch population. Different films were used to investigate how they would impact pain sensitivity and what influence sex and other variables have on the effect of this simple intervention.

METHODS

We performed a study consisting of 2 parts: (1) a cross-sectional research to investigate pain sensitivity differences between men and women and the influence of other demographic variables on the pain sensitivity in a Dutch cohort and (2) an internet intervention study to determine whether a short film could skew pain sensitivity.

RESULTS

All respondents filled in a web-based demographic questionnaire and were randomized into 4 groups. The control group filled in the Pain Sensitivity Questionnaire without watching a preliminary film. A cross-sectional analysis was performed in the control group (n=1746). The other 3 groups watched short films: one group watched a film with scenes of nature (n=2650), another group watched a film on laughing people (n=2735), and the last group watched a film on physically painful events (n=2708). Immediately after the film viewing, participants were directed to the Pain Sensitivity Questionnaire to measure their pain sensitivity. The Pain Sensitivity Questionnaire score was stated as a mean per question on the numeric rating scale from 0-1. The cross-sectional study revealed no significant differences between men and women but showed male-female differences in the Pain Sensitivity Questionnaire when specific background factors were present. Watching a short film had a positive impact on the pain sensitivity of the respondents who had chronic pain, with a higher effect observed in female respondents.

CONCLUSIONS

Scientists performing pain research need to account for factors that can influence the outcome of their study and be aware that these factors can be sex-dependent, and pain sensitivity should be analyzed accordingly. Even relatively small interventions such as watching a film can impact pain sensitivity, especially in respondents with current chronic pain. This effect can vary as well when different background factors are present. Our findings warrant further explorations of the possibilities that simple interventions bring for patients in personalized medicine.

TRIAL REGISTRATION

Landelijk Trial Register NTR-new NL8182; https://onderzoekmetmensen.nl/en/trial/29537.

Pains Revisited

OBJECTIVES

The management of pain patients has not evolved as rapidly as envisioned when IASP was founded almost 50 years ago. We sought to identify factors that could contribute to this situation, with a focus on concepts of pain and the education of pain physicians.

METHODS

Relevant literature describing new strategies for diagnosing and managing patients with high-impact chronic pain was reviewed.

RESULTS

It appears that the acute-chronic dichotomy has outlived its usefulness and pains should be identified as of peripheral origin or due to central processing errors. Pains of peripheral origin and those of central processing errors require different diagnostic and therapeutic strategies.

DISCUSSION

Peripheral treatments and opioids are not effective for central pains. When the cause of the pain lies in the central nervous system, a more centrally focused approach is needed to minimize wasteful pursuit of peripheral causes. The education and training of pain physicians should reflect the skills needed to address these 2 very different clinical problems.

Neuropathic pain has sex-specific effects on oxycodone-seeking and non-drug-seeking ensemble neurons in the dorsomedial prefrontal cortex of mice

Approximately 50 million Americans suffer from chronic pain, and nearly a quarter of chronic pain patients have reported misusing opioid prescriptions. Repeated drug seeking is associated with reactivation of an ensemble of neurons sparsely scattered throughout the dorsomedial prefrontal cortex (dmPFC). Prior research has demonstrated that chronic pain increases intrinsic excitability of dmPFC neurons, which may increase the likelihood of reactivation during drug seeking. We tested the hypothesis that chronic pain would increase oxycodone-seeking behaviour and that the pain state would differentially increase intrinsic excitability in dmPFC drug-seeking ensemble neurons. TetTag mice self-administered intravenous oxycodone. After 7 days of forced abstinence, a drug-seeking session was performed, and the ensemble was tagged. Mice received spared nerve injury (SNI) to induce chronic pain during the period between the first and second seeking session. Following the second seeking session, we performed electrophysiology on individual neurons within the dmPFC to assess intrinsic excitability of the drug-seeking ensemble and non-ensemble neurons. SNI had no impact on sucrose seeking or intrinsic excitability of dmPFC neurons from these mice. In females, SNI increased oxycodone seeking and intrinsic excitability of non-ensemble neurons. In males, SNI had no impact on oxycodone seeking or neuron excitability. Data from females are consistent with clinical reports that chronic pain can promote drug craving and relapse and support the hypothesis that chronic pain itself may lead to neuroadaptations which promote opioid seeking.

Assessing Risk Factors and Comorbidities in the Treatment of Chronic Pain: A Narrative Review

PURPOSE OF REVIEW

Chronic pain affects a significant portion of the population globally, making it a leading cause of disability. Understanding the multifaceted nature of chronic pain, its various types, and the intricate relationship it shares with risk factors, comorbidities, and mental health issues like depression and anxiety is critical for comprehensive patient care. Factors such as socioeconomic status (SES), age, gender, and obesity collectively add layers of complexity to chronic pain experiences and pose management challenges.

RECENT FINDINGS

Low SES presents barriers to effective pain care, while gender differences and the prevalence of chronic pain in aging adults emphasize the need for tailored approaches. The association between chronic pain and physical comorbidities like cardiovascular disease, chronic obstructive pulmonary disease (COPD), and diabetes mellitus reveals shared risk factors and further highlights the importance of integrated treatment strategies. Chronic pain and mental health are intricately linked through biochemical mechanisms, profoundly affecting overall quality of life. This review explores pharmacologic treatment for chronic pain, particularly opioid analgesia, with attention to the risk of substance misuse and the ongoing opioid epidemic. We discuss the potential role of medical cannabis as an alternative treatment with a nuanced perspective on its impact on opioid use. Addressing the totality and complexity of pain states is crucial to individualizing chronic pain management. With different types of pain having different underlying mechanisms, considerations should be made when approaching their treatment. Moreover, the synergistic relationship that pain states can have with other comorbidities further complicates chronic pain conditions.

Inflammation, lipid dysregulation, and transient receptor potential cation channel subfamily V member 4 signaling perpetuate chronic vulvar pain

ABSTRACT

Localized provoked vulvodynia is characterized by chronic vulvar pain that disrupts every aspect of the patient's life. Pain is localized to the vulvar vestibule, a specialized ring of tissue immediately surrounding the vaginal opening involved in immune defense. In this article, we show inflammation is the critical first step necessary for the generation of pain signals in the vulva. Inflammatory stimuli alone or combined with the transient receptor potential cation channel subfamily V member 4 (TRPV4) agonist 4α-phorbol 12,13-didecanoate stimulate calcium flux into vulvar fibroblast cells. Activity is blocked by the TRPV4 antagonist HC067047, denoting specificity to TRPV4. Using lipidomics, we found pro-resolving lipids in the vulvar vestibule were dysregulated, characterized by a reduction in pro-resolving mediators and heightened production of inflammatory mediators. We demonstrate specialized pro-resolving mediators represent a potential new therapy for vulvar pain, acting on 2 key parts of the disease mechanism by limiting inflammation and acutely inhibiting TRPV4 signaling.

Development and validation of a predictive model for persistent opioid use in new opioid analgesic users via a nationwide claims database

BACKGROUND

Chronic opioid use is associated with problematic opioid use, such as opioid abuse. It is important to develop a prediction model for safe opioid use. In this study, we aimed to develop and validate a risk score model for chronic opioid use in opioid-naïve, noncancer patients, using data from a nationwide database.

METHODS

Data from the National Health Insurance Claims Database in the Republic of Korea from 2016 to 2018 were used, and adult, noncancer patients who were started on non-injectable opioid analgesics (NIOAs) were included. The risk score model was developed using the β coefficient of each variable in the multivariable logistic regression analysis.

RESULTS

Overall, 676,676 noncancer patients were started on NIOAs, of which 65,877 (9.7%) were prescribed NIOAs chronically. Age, baseline healthcare utilization, comorbidities, co-medications, and pattern of first NIOA prescription were identified as risk factors for chronic opioid use. The c-static for the performance of our risk score model was 0.754 (95% confidence interval, 0.750-0.758).

CONCLUSION

To our knowledge, this is the first tool that can predict chronic opioid use in the Korean population. The model can help physicians examine the risk of chronic opioid use by patients who are started on NIOA.

A novel theta-controlled vibrotactile brain-computer interface to treat chronic pain: a pilot study

Limitations in chronic pain therapies necessitate novel interventions that are effective, accessible, and safe. Brain-computer interfaces (BCIs) provide a promising modality for targeting neuropathology underlying chronic pain by converting recorded neural activity into perceivable outputs. Recent evidence suggests that increased frontal theta power (4-7 Hz) reflects pain relief from chronic and acute pain. Further studies have suggested that vibrotactile stimulation decreases pain intensity in experimental and clinical models. This longitudinal, non-randomized, open-label pilot study's objective was to reinforce frontal theta activity in six patients with chronic upper extremity pain using a novel vibrotactile neurofeedback BCI system. Patients increased their BCI performance, reflecting thought-driven control of neurofeedback, and showed a significant decrease in pain severity (1.29 ± 0.25 MAD, p = 0.03, q = 0.05) and pain interference (1.79 ± 1.10 MAD p = 0.03, q = 0.05) scores without any adverse events. Pain relief significantly correlated with frontal theta modulation. These findings highlight the potential of BCI-mediated cortico-sensory coupling of frontal theta with vibrotactile stimulation for alleviating chronic pain.

How do opioids control pain circuits in the brainstem during opioid-induced disorders and in chronic pain? Implications for the treatment of chronic pain

ABSTRACT

Brainstem areas involved in descending pain modulation are crucial for the analgesic actions of opioids. However, the role of opioids in these areas during tolerance, opioid-induced hyperalgesia (OIH), and in chronic pain settings remains underappreciated. We conducted a revision of the recent studies performed in the main brainstem areas devoted to descending pain modulation with a special focus on the medullary dorsal reticular nucleus (DRt), as a distinctive pain facilitatory area and a key player in the diffuse noxious inhibitory control paradigm. We show that maladaptive processes within the signaling of the µ-opioid receptor (MOR), which entail desensitization and a switch to excitatory signaling, occur in the brainstem, contributing to tolerance and OIH. In the context of chronic pain, the alterations found are complex and depend on the area and model of chronic pain. For example, the downregulation of MOR and δ-opioid receptor (DOR) in some areas, including the DRt, during neuropathic pain likely contributes to the inefficacy of opioids. However, the upregulation of MOR and DOR, at the rostral ventromedial medulla, in inflammatory pain models, suggests therapeutic avenues to explore. Mechanistically, the rationale for the diversity and complexity of alterations in the brainstem is likely provided by the alternative splicing of opioid receptors and the heteromerization of MOR. In conclusion, this review emphasizes how important it is to consider the effects of opioids at these circuits when using opioids for the treatment of chronic pain and for the development of safer and effective opioids.

Can cannabidiol have an analgesic effect?

BACKGROUND

Cannabis, more commonly known as marijuana or hemp, has been used for centuries to treat various conditions. Cannabis contains two main components cannabidiol (CBD) and tetrahydrocannabinol (THC). CBD, unlike THC, is devoid of psychoactive effects and is well tolerated by the human body but has no direct effect on the receptors of the endocannabid system, despite the lack of action on the receptors of the endocannabid system.

OBJECTIVES AND METHODS

We have prepared a literature review based on the latest available literature regarding the analgesic effects of CBD. CBD has a wide range of effects on the human body. In this study, we will present the potential mechanisms responsible for the analgesic effect of CBD. To the best of our knowledge, this is the first review to explore the analgesic mechanisms of CBD.

RESULTS AND CONCLUSION

The analgesic effect of CBD is complex and still being researched. CBD models the perception of pain by acting on G protein-coupled receptors. Another group of receptors that CBD acts on are serotonergic receptors. The effect of CBD on an enzyme of potential importance in the production of inflammatory factors such as cyclooxygenases and lipoxygenases has also been confirmed. The presented potential mechanisms of CBD's analgesic effect are currently being extensively studied.

Complementary and alternative medicine carts in the inpatient rehabilitation unit: Access and nurses' use

PURPOSE

To determine if increased accessibility to complementary and alternative medicine (CAM) increases the usage of CAM interventions.

METHODS

A prospective pre-post study with a "run-in" design in a hospital with two inpatient rehabilitation floors was used. Data were analyzed with SAS v9.4.

RESULTS

CAM use before implementation was 2.8 (1.0); after implementation, 3.1 (0.56).

CONCLUSION

Greater access to CAM materials did not significantly increase their use (P = .233). Aromatherapy was used more after increased availability, but heat and cold application decreased. Nurses valued CAM even though independent practice was not fully supported.

Anti-inflammatory and antinociceptive effects, and safety toxicological profile of a new paracetamol analog, LQFM291

In the scope of a research program with the goal of developing treatments for inflammatory diseases, the pharmacological evaluation of LQFM291, designed by molecular hybridization from butylated hydroxytoluene and paracetamol, was described. The antioxidant profile of LQFM291 was evaluated by electrochemical measurement. Also, acute or repeated treatments with equimolar doses to paracetamol were used to evaluate the antinociceptive and/or anti-inflammatory activities of LQFM291 in animal models. The toxicologic potential of LQFM291 was also evaluated and compared to paracetamol through biochemical and histopathological analysis after the repeated treatment schedule. As a result of the acute treatment, paracetamol showed a similar antinociceptive effect in formalin test compared to LQFM291. Whereas, after the repeated treatment, when carrageenan-induced hyperalgesia and edema tests were performed, paracetamol showed a delayed antinociceptive and anti-inflammatory effect compared to LQFM291. Furthermore, as other advantages the LQFM291 showed a high redox capacity, a gastroprotective activity and a safety pharmacological profile without any liver or kidney damage. These effects can be related to the prevention of oxidative stress by reduction of protein and lipid peroxidation in gastric tissue, maintenance of glutathione levels in hepatic homogenate, and a systemic reduction of pro-inflammatory cytokine levels, which may characterize the LQFM291 as a more viable and effective alternative to relief pain and inflammatory signs in patients with chronic disorders.

Questioning the Right to Pain Relief and Its Role in the Opioid Epidemic

The new discipline of palliative care helped to establish the right to pain relief at the end of life and the necessity of using opioids to achieve that goal. Professional pain organizations followed the United Nations' model for universal human rights in their declaration of a universal right to pain management. Both palliative care and pain medicine specialties worked to establish pain as a legitimate focus of medical treatment separate from its association with disease. Pain intensity became the metric used to determine the need for treatment and the success of that treatment. Opioids were favored as the most reliable and feasible means to reduced pain intensity. The Harrison Act of 1914 restricted legitimate opioid use to that prescribed by medical professionals as analgesics. This legislation helped establish opioids as specific painkillers that had a distinct capacity to induce addiction. This understanding of opioids as having distinct and separable analgesic and addictive potential was challenged by the 1970s discovery of an endogenous opioid system, which integrates pain and reward functions to support survival. Our modern pain neurophysiology places the patient with pain in a passive position from which it makes sense to assert a right to pain relief. To prevent future opioid epidemics we need to abandon clinical outpatient use of pain intensity scores and redefine the medical necessity of pain treatment as less about the reduction of pain intensity and more about the capacity to pursue personally valued activities.

Nitro-benzylideneoxymorphone, a bifunctional mu and delta opioid receptor ligand with high mu opioid receptor efficacy

Introduction: There is a major societal need for analgesics with less tolerance, dependence, and abuse liability. Preclinical rodent studies suggest that bifunctional ligands with both mu (MOPr) and delta (DOPr) opioid peptide receptor activity may produce analgesia with reduced tolerance and other side effects. This study explores the structure-activity relationships (SAR) of our previously reported MOPr/DOPr lead, benzylideneoxymorphone (BOM) with C7-methylene-substituted analogs. Methods: Analogs were synthesized and tested in vitro for opioid receptor binding and efficacy. One compound, nitro-BOM (NBOM, 12) was evaluated for antinociceptive effects in the warm water tail withdrawal assay in C57BL/6 mice. Acute and chronic antinociception was determined, as was toxicologic effects on chronic administration. Molecular modeling experiments were performed using the Site Identification by Ligand Competitive Saturation (SILCS) method. Results: NBOM was found to be a potent MOPr agonist/DOPr partial agonist that produces high-efficacy antinociception. Antinociceptive tolerance was observed, as was weight loss; this toxicity was only observed with NBOM and not with BOM. Modeling supports the hypothesis that the increased MOPr efficacy of NBOM is due to the substituted benzylidene ring occupying a nonpolar region within the MOPr agonist state. Discussion: Though antinociceptive tolerance and non-specific toxicity was observed on repeated administration, NBOM provides an important new tool for understanding MOPr/DOPr pharmacology.

Opioid Agents and Cardiac Arrhythmia: A Literature Review

Opioids are compounds that cause similar effects to morphine by binding to its receptors. Opioids can be synthetic, semi-synthetic, or natural and can easily bind to the receptors of opioids in order to depict their effects, which may vary depending upon the exposure of the drug and its dose. However, several side effects of opioids can also be observed, with the most crucial being their impact on the heart's electrical activity. This review majorly focuses on opioids' impact on the prolongation of the QT curve and their arrhythmogenic susceptibility. Articles published up to the year 2022 in various databases were identified and searched with the use of keywords. Search terms included "cardiac arrhythmias," "QT interval," "opioids," "opioid dependence," and "torsade de pointes (TdP)". These terms highlight the impact of each opioid agent on the activity of the heart on an electrocardiogram. The results of the available data depict that opioids, such as methadone, pose higher risks, even when taken in smaller amounts, and have the capability for QT interval prolongation and TdP development. A variety of opioids, i.e., oxycodone and tramadol, are considered as intermediary risk drugs and can build long QT intervals and TdP in large doses. Several other opioids are considered low-risk drugs, including buprenorphine and morphine, which lead to no production of TdP and QT interval prolongation in daily routine doses. Evidence indicates a high risk of sinus bradycardia, atrial fibrillation, cardiac block, and supra-ventricular arrhythmias in opium consumers. This literature review will play a key role in determining the association between the use of opioids and cardiac arrhythmias. It will further highlight the practical implications of opioids for the management of cardiac issues based on their dose, frequency, and intensity. Moreover, it will also depict the adverse effects of opioids along with their dose-specific relationship. Opioids display disparate cardiac arrhythmogenicity, and methadone contains a greater ability to induce long QT intervals and hazardous arrhythmias at conventional doses. In order to reduce arrhythmogenic risk, opioids taken in large amounts should be monitored with a regular electrocardiogram in high-risk consumers, i.e., patients on opioid maintenance.

Assessing Opioid Abuse in Chronic Pain Patients: Further Validation of the Prescription Opioid Misuse Index (POMI) Using Item Response Theory

Due the limitations of the previous validations, the purpose of this study was to further validate the Prescription Opioid Misuse Index (POMI) in a larger sample of chronic non-cancer pain (CNCP) patients and to examine differential item functioning (DIF) across sex. Participants (n=225 CNCP patients under long-term opioid therapy) completed patient characteristics, self-reported POMI and DSM-5 prescription opioid use disorder measurements. Reliability and factor structure were assessed using both item response theory and classical test theory. ROC curve analysis was used to establish the optimum cut-off score for detecting the presence of DSM-5 prescription opioid-use disorder. Concurrent validity was also tested. The POMI showed a unidimensional factor structure and acceptable internal consistency (ωcat =0.62). DIF analysis showed that males and females respond similarly to each item of the POMI, supporting unbiased measurement of the latent trait across both groups. A cut-off point of 2 is suggested in order to maximize the accuracy of the instrument as a first-screening tool for opioid misuse (AUC=0.78; p<0.001; CI 95%: 0.72–0.85). Concurrent validity of the POMI was high with DSM-5 moderate to severe opioid-use disorder criteria (OR=7.824, p<0.001). These results indicate that the POMI is a valid and clinically feasible screening instrument for detecting CNCP patients who misuse opioid medications. The short length of the scale could meet the needs of clinical practice as it allows clinicians to precisely identify and monitor prescription opioid misuse in both male and female patients.

Sequential and Comparative Evaluation of Pain Treatment Effectiveness Response (SCEPTER), a pragmatic trial for conservative chronic low back pain treatment

BACKGROUND

Chronic low back pain (cLBP) is a common and highly disabling problem world-wide. Although many treatment options exist, it is unclear how to best sequence the multitude of care options to provide the greatest benefit to patients.

METHODS

The Sequential and Comparative Evaluation of Pain Treatment Effectiveness Response (SCEPTER) trial uses a pragmatic, randomized, stepped design. Enrollment targets 2529 participants from 20 Veterans Affairs (VA) medical centers. Participants with chronic low back pain will first be randomized to one of three options: 1) an internet-based self-management program (Pain EASE); 2) a tailored physical therapy program (Enhanced PT); or 3) continued care with active monitoring (CCAM), a form of usual care. Participants not achieving a 30% or 2-point reduction on the study's primary outcome (Brief Pain Inventory Pain Interference (BPI-PI) subscale), 3 months after beginning treatment may undergo re-randomization in a second step to cognitive behavioral therapy for chronic pain, spinal manipulation therapy, or yoga. Secondary outcomes include pain intensity, back pain-related disability, depression, and others. Participants will be assessed every three months until 12 months after initiating their final trial therapy. Companion economic and implementation analyses are also planned.

RESULTS

The SCEPTER trial is currently recruiting and enrolling participants.

CONCLUSIONS

Trial results will inform treatment decisions for the stepped management of chronic low back pain - a common and disabling condition. Additional analyses will help tailor treatment selection to individual patient characteristics, promote efficient resource use, and identify implementation barriers of interventions.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT04142177.

Optimizing and Accelerating the Development of Precision Pain Treatments for Chronic Pain: IMMPACT Review and Recommendations

Large variability in the individual response to even the most-efficacious pain treatments is observed clinically, which has led to calls for a more personalized, tailored approach to treating patients with pain (ie, "precision pain medicine"). Precision pain medicine, currently an aspirational goal, would consist of empirically based algorithms that determine the optimal treatments, or treatment combinations, for specific patients (ie, targeting the right treatment, in the right dose, to the right patient, at the right time). Answering this question of "what works for whom" will certainly improve the clinical care of patients with pain. It may also support the success of novel drug development in pain, making it easier to identify novel treatments that work for certain patients and more accurately identify the magnitude of the treatment effect for those subgroups. Significant preliminary work has been done in this area, and analgesic trials are beginning to utilize precision pain medicine approaches such as stratified allocation on the basis of prespecified patient phenotypes using assessment methodologies such as quantitative sensory testing. Current major challenges within the field include: 1) identifying optimal measurement approaches to assessing patient characteristics that are most robustly and consistently predictive of inter-patient variation in specific analgesic treatment outcomes, 2) designing clinical trials that can identify treatment-by-phenotype interactions, and 3) selecting the most promising therapeutics to be tested in this way. This review surveys the current state of precision pain medicine, with a focus on drug treatments (which have been most-studied in a precision pain medicine context). It further presents a set of evidence-based recommendations for accelerating the application of precision pain methods in chronic pain research. PERSPECTIVE: Given the considerable variability in treatment outcomes for chronic pain, progress in precision pain treatment is critical for the field. An array of phenotypes and mechanisms contribute to chronic pain; this review summarizes current knowledge regarding which treatments are most effective for patients with specific biopsychosocial characteristics.

Stability of Abuse-deterrent properties of PEO-based Abuse-deterrent formulation

Abuse of opioid drug products is a national health crisis in the US. To deter abuse, a number of drug products with abuse-deterrent (AD) properties have been approved by the US Food and Drug Administration (FDA). For abuse deterrence, it is critical to maintain the AD properties during the product shelf life. However, no information on the stability of AD properties during product shelf life is publicly available. In this study, stability of AD properties of surrogate AD formulation (ADF) of opioid active pharmaceutical ingredients (APIs) were studied. Surrogate extended release (ER) AD tablets were prepared by direct compression using Diltiazem HCl (model drug), polyethylene oxide (PEO WSR 301) polymer and magnesium stearate followed by curing at 70 °C for 30 mins. The stability studies were conducted at 25 °C/60 % RH and 40 °C/75 % RH storage conditions for 12 months (M) and 6 months (M), respectively. In vitro characterization and evaluation of AD properties of tablets were performed. As anticipated, the curing process increased the crushing strength of the tablets. However, the tablets could still be manipulated and compromised leading to an enhancement in the amount of drug extracted in solvents (e.g., water, alcohol), regardless of extraction temperature as well as tablet storage condition and time. Furthermore, the granule particle size as well as viscosity in water of manipulated samples were found to be lower for tablets stored at 25 °C/60 % RH or 40 °C/75 % RH for 12 M or 3 M/6M, respectively. The changes in AD properties eased the syringeability of hydrated samples and ultimately led to the withdrawal of higher amounts of drug into the syringe, thereby, impacting the abuse deterrence potential of the formulation by an IV route. These data demonstrated that the stability of AD properties (i.e., granule particle size, viscosity and syringeability-injectability) of PEO-based tablets was dependent on the storage condition. In conclusion, the design of AD formulation and setting of product quality profile should take into consideration the stability of AD properties during the product shelf life.

Tapentadol: A Review of Experimental Pharmacology Studies, Clinical Trials, and Recent Findings

Tapentadol is an analgesic compound that acts centrally to attenuate pain. Previous studies have shown that tapentadol has dual mechanisms of action as a mu-opioid receptor agonist and noradrenaline re-uptake inhibition. Therefore, tapentadol provides a great advantage over classic opioids in pain management from nociceptive to neuropathic. Cumulative evidence from in vitro data suggests that tapentadol effect of norepinephrine re-uptake could be a new target that overcomes other classic opioids in chronic neuropathic pain. Compared to tramadol and other opioids, tapentadol is associated with fewer adverse effects than tramadol. Tapentadol is a new alternative to treat acute, chronic, and neuropathic pain. Thus, this review article was focused on understanding the studies that led to the development of tapentadol as a novel analgesic drug and its advantages over conventional opioids. Thus, tapentadol is a good alternative with fewer adverse effects and is available for human use.

Breathing Exercises for Pain Management in Cancer Survivors: A Systematic Review

OBJECTIVES

Unmanaged pain significantly affects cancer survivors' quality of life. Nurses should play a significant role in pain management through non-pharmacological interventions. This review aims to explore the efficacy and safety of breathing exercises for pain management in all cancer survivors.

DESIGN

A systematic review.

DATA SOURCES

Thirteen databases, including PubMed, EMBase, CENTRAL, MEDLINE, CINAHL, JBI, Science Direct, Scopus, SocINDEX, Web of Science, PsycINFO, CNKI, and Wan Fang, were searched from inception to May, 2021.

REVIEW/ANALYSIS METHODS

Studies that focused on the efficacy of breathing exercises for pain management, regardless of the age of the cancer survivors, were included. Cochrane tools were used for the quality appraisal of the included studies. Because of the limited number of studies, descriptive data analysis was used to summarize the results.

RESULTS

Ten studies were included. Slow pursed lip breathing showed benefits for post-surgical pain. Contradictory findings were identified in the Enhanced Recovery After Surgery for post-surgical pain. Slow deep breathing and Hey-Hu regular breathing techniques were effective for pain management in pediatric cancer patients. The Active Cycle of Breathing Technique and five-minute mindful breathing did not have any statistically significant effects on pain relief. Quality of life was measured in three studies, with some improvement. Only one study addressed adverse events and reported that no adverse events occurred.

CONCLUSIONS

Breathing exercises may be a promising approach to pain relief in cancer survivors. However, more rigorously designed studies are required to establish the evidence.

COVID-19 infection and pain in adolescents with sickle cell disease: A case series

Adolescents with sickle cell disease (SCD) have been shown to have pain-related sequelae following COVID-19 infection. In this case series, we discuss five adolescents with SCD and SARS-CoV-2 infection who subsequently developed complex pain circumstances manifested as: (1) increased frequency of acute care visits or admissions for pain; (2) new onset chronic pain; (3) new onset neuropathic pain; (4) escalation in the complexity of pharmacologic therapies; (5) increased use of nonpharmacologic interventions. While more research is needed to fully understand the implications of COVID-19 infection on pain in adolescents with SCD, these cases suggest the presence of a complex relationship.

Knowing the Enemy Is Halfway towards Victory: A Scoping Review on Opioid-Induced Hyperalgesia

Opioid-induced hyperalgesia (OIH) is a paradoxical effect of opioids that is not consensually recognized in clinical settings. We conducted a revision of clinical and preclinical studies and discuss them side by side to provide an updated and renewed view on OIH. We critically analyze data on the human manifestations of OIH in the context of chronic and post-operative pain. We also discuss how, in the context of cancer pain, though there are no direct evidence of OIH, several inherent conditions to the tumor and chemotherapy provide a substrate for the development of OIH. The review of the clinical data, namely in what concerns the strategies to counter OIH, emphasizes how much OIH rely mechanistically on the existence of µ-opioid receptor (MOR) signaling through opposite, inhibitory/antinociceptive and excitatory/pronociceptive, pathways. The rationale for the maladaptive excitatory signaling of opioids is provided by the emerging growing information on the functional role of alternative splicing and heteromerization of MOR. The crossroads between opioids and neuroinflammation also play a major role in OIH. The latest pre-clinical data in this field brings new insights to new and promising therapeutic targets to address OIH. In conclusion, although OIH remains insufficiently recognized in clinical practice, the appropriate diagnosis can turn it into a treatable pain disorder. Therefore, in times of scarce alternatives to opioids to treat pain, mainly unmanageable chronic pain, increased knowledge and recognition of OIH, likely represent the first steps towards safer and efficient use of opioids as analgesics.

Buprenorphine/naloxone versus methadone opioid rotation in patients with prescription opioid use disorder and chronic pain: study protocol for a randomized controlled trial

Background

Opioids are effective in pain-management, but long-term opioid users can develop prescription opioid use disorder (OUD). One treatment strategy in patients with OUD is rotating from a short-acting opioid to a long-acting opioid (buprenorphine/naloxone (BuNa) or methadone). Both BuNa and methadone have been shown to be effective strategies in patients with OUD reducing opioid misuse, however data on head-to-head comparison in patients with chronic non-malignant pain and prescription OUD are limited.

Methods

This two-armed open-label, randomized controlled trial aims to compare effectiveness between BuNa and methadone in patients with chronic non-malignant with prescription OUD (n = 100). Participants receive inpatient rotation to either BuNa or methadone with a flexible dosing regimen. The primary outcome is opioid misuse 2 months after rotation. Secondary outcomes include treatment compliance, side effects, analgesia, opioid craving, quality of life, mood symptoms, cognitive and physical functioning over 2- and 6 months follow-up. Linear mixed model analysis will be used to evaluate change in outcome parameters over time between the treatment arms.

Discussion

This is one of the first studies comparing buprenorphine/naloxone and methadone for treating prescription OUD in a broad patient group with chronic non-malignant pain. Results may guide future treatment for patients with chronic pain and prescription OUD.

Trial registrationhttps://www.trialregister.nl/, NL9781

Case Report: De Novo and Persistent Psychosis After Withdrawal From Chronic Opioid Therapy

Psychiatric illness is associated with both chronic pain syndromes and opioid use disorder, further complicating how we care for patients with psychiatric issues. We report a unique case of a de novo and persistent psychotic disorder after complicated opioid withdrawal in a patient without any psychiatric history. The patient developed persistent auditory hallucinations after discontinuation of chronic opioid therapy that responded only to atypical antipsychotic (olanzapine) treatment. This case illustrates the neuropsychiatric effects of chronic opioid exposure, as well as layered clinical management dimensions related to opioid detoxification and psychosis treatment. Long-term opioid therapy may have lasting neuropsychiatric effects, including playing a role in the development and/or expression of psychotic disorders. Here we review the limited literature on the effects of opioids on psychosis. This complex case also demonstrates a clinical approach for effectively co-managing psychiatric symptoms in the context of chronic pain and chronic opioid therapy.

Midazolam, methamphetamine, morphine and nicotine intake in high‐drinking‐in‐the‐dark mice

The high-drinking-in-the-dark (HDID) lines of mice were selectively bred for achieving high blood alcohol levels in the drinking-in-the-dark (DID) task and have served as a unique genetic risk model for binge-like alcohol intake. However, little is known about their willingness to consume other addictive drugs. Here, we examined (a) whether the HDID-1 and HDID-2 lines of mice would voluntarily consume midazolam, methamphetamine, morphine and nicotine in a DID test and (b) whether the HDID lines differ from their founders, heterogeneous stock/Northport (HS/NPT), in consumption levels of these drugs at the concentrations tested. Separate groups of HDID-1, HDID-2 and HS/NPT mice were given 4 days of access to each drug, using the single-bottle, limited-access DID paradigm. Male and female mice of both HDID lines consumed all four offered drugs. We observed no genotype differences in 40 μg/ml methamphetamine intake, but significant differences in nicotine, midazolam and morphine intake. Both HDID lines drank significantly more (150 μg/ml) midazolam than their founders, providing strong support for a shared genetic contribution to binge ethanol and midazolam intake. HDID-2 mice, but not HDID-1 mice, consumed more morphine (700 μg/ml) and more nicotine across a range of concentrations than HS/NPT mice. These results demonstrate that the HDID mice can be utilized for tests of voluntary drug consumption other than ethanol and highlight potentially important differences between HDID lines in risk for elevated drug intake.

Chronic Opioid Use and Sleep Disorders

Opioid medications are considered a significant component in the multidisciplinary management of chronic pain. In the past two decades, the use of opioid medications has dramatically risen in part because of an increased awareness by health care providers to treat chronic pain more effectively. In addition, patients are encouraged to seek treatment. The release of a sentinel joint statement in 1997 by the American Academy of Pain Medicine and the American Pain Society in a national effort to increase awareness and support the treatment of chronic pain has undoubtedly contributed to the opioid crisis.

Pain patterns in chronic pancreatitis and chronic primary pain

BACKGROUND

Abdominal pain is the most distressing symptom of chronic pancreatitis (CP), and current treatments show limited benefit. Pain phenotypes may be more useful than diagnostic categories when planning treatments, and the presence or absence of constant pain in CP may be a useful prognostic indicator.

AIMS

This cross-sectional study examined dimensions of pain in CP, compared pain in CP with chronic primary pain (CPP), and assessed whether constant pain in CP is associated with poorer outcomes.

METHODS

Patients with CP (N = 91) and CPP (N = 127) completed the Comprehensive Pancreatitis Assessment Tool. Differences in clinical characteristics and pain dimensions were assessed between a) CP and CPP and b) CP patients with constant versus intermittent pain. Latent class regression analysis was performed (N = 192) to group participants based on pain dimensions and clinical characteristics.

RESULTS

Compared to CPP, CP patients had higher quality of life (p < 0.001), lower pain severity (p < 0.001), and were more likely to use strong opioids (p < 0.001). Within CP, constant pain was associated with a stronger response to pain triggers (p < 0.05), greater pain spread (p < 0.01), greater pain severity, more features of central sensitization, greater pain catastrophising, and lower quality of life compared to intermittent pain (all p values ≤ 0.001). Latent class regression analysis identified three groups, that mapped onto the following patient groups 1) combined CPP and CP-constant, 2) majority CPP, and 3) majority CP-intermittent.

CONCLUSIONS

Within CP, constant pain may represent a pain phenotype that corresponds with poorer outcomes. CP patients with constant pain show similarities to some patients with CPP, potentially indicating shared mechanisms.

The Role of Resilience, Happiness, and Social Support in the Psychological Function during the Late Stages of the Lockdown in Individuals with and without Chronic Pain

There is mounting evidence to suggest that individuals with chronic pain adjusted poorly to and were impacted negatively by social distancing measures during the lockdown. However, there is limited data on the factors that might protect against the negative effects associated with social distancing measures, as most research has been conducted in the general population and in the initial stages of the lockdown. The aim of this study was to improve the understanding of the role that resilience, happiness, and social support, all factors that are thought to have a protective role, played in the psychological function (measured as anxiety, depression, and stress) to the social distancing measures during the late stages of the lockdown in a sample of adults with and without chronic pain living in Spain. A group of 434 adults responded to an online survey and provided information on sociodemographic issues, which included measures of pain, perceived health and quality of life, depression, anxiety, stress, resilience, happiness, and social support. The data showed that individuals with chronic pain (N = 200; 46%) reported statistically significant worst psychological function, that is to say, they reported higher levels of anxiety, depression, and stress (all ps < 0.001). Resilience, social support, and happiness proved to be significant predictors of anxiety, depression, and stress, after controlling for the effects of age, gender, and chronic pain. Although the effect sizes were small to medium, they are consistent with the findings of other studies. The findings from this study provide important additional new information regarding the associations between resilience, happiness, and social support and the adjustment to the social distancing measures during the late stages of the lockdown. These findings can be used to develop programs to improve adjustment to and coping with the demands of social distancing measures.

Structural Investigation of the Interaction Mechanism between Chlorogenic Acid and AMPA Receptor via In Silico Approaches

Chlorogenic acid (CGA), an important metabolite in natural plant medicines such as honeysuckle and eucommia, has been shown to have potent antinociceptive effects. Nevertheless, the mechanism by which CGA relieves chronic pain remains unclear. α-amino-3-hydroxy-5-methyl-4-isooxazolpropionic acid receptor (AMPAR) is a major ionotropic glutamate receptor that mediates rapid excitatory synaptic transmission and its glutamate ionotropic receptor AMPA type subunit 1 (GluA1) plays a key role in nociceptive transmission. In this study, we used Western blot, surface plasmon resonance (SPR) assay, and the molecular simulation technologies to investigate the mechanism of interaction between CGA and AMPAR to relieve chronic pain. Our results indicate that the protein expression level of GluA1 showed a dependent decrease as the concentration of CGA increased (0, 50, 100, and 200 μM). The SPR assay demonstrates that CGA can directly bind to GluA1 (K_D = 496 μM). Furthermore, CGA forms a stable binding interaction with GluA1, which is validated by molecular dynamics (MD) simulation. The binding free energy between CGA and GluA1 is -39.803 ± 14.772 kJ/mol, where van der Waals interaction and electrostatic interaction are the major contributors to the GluA1-CGA binding, and the key residues are identified (Val-32, Glu-33, Ala-36, Glu-37, Leu-48), which play a crucial role in the binding interaction. This study first reveals the structural basis of the stable interaction between CGA and GluA1 to form a binding complex for the relief of chronic pain. The research provides the structural basis to understand the treatment of chronic pain and is valuable to the design of novel drug molecules in the future.

Digital Analgesic Comprising a Second-Generation Digital Health System: Increasing Effectiveness by Optimizing the Dosing and Minimizing Side Effects

Opioids remain an essential part of the treatment of chronic pain. However, their use and increasing rates of misuse are associated with high morbidity and mortality. The development of tolerance to opioids and analgesics further complicates dosing and the need to reduce side effects. First-generation digital systems were developed to improve analgesics but are not always capable of making clinically relevant associations and do not necessarily lead to better clinical efficacy. A lack of improved clinical outcomes makes these systems less applicable for adoption by clinicians and patients. There is a need to enhance the therapeutic regimens of opioids. In the present paper, we present the use of a digital analgesic that consists of an analgesic administered under the control of a second-generation artificial intelligence system. Second-generation systems focus on improved patient outcomes measured based on clinical response and reduced side effects in a single subject. The algorithm regulates the administration of analgesics in a personalized manner. The digital analgesic provides advantages for both users and providers. The system enables dose optimization, improving effectiveness, and minimizing side effects while increasing adherence to beneficial therapeutic regimens. The algorithm improves the clinicians’ experience and assists them in managing chronic pain. The system reduces the financial burden on healthcare providers by lowering opioid-related morbidity and provides a market disruptor for pharma companies.

Goofballing of Opioid and Methamphetamine: The Science Behind the Deadly Cocktail

Globally, millions of people suffer from various substance use disorders (SUD), including mono-and polydrug use of opioids and methamphetamine. Brain regions such as the cingulate cortex, infralimbic cortex, dorsal striatum, nucleus accumbens, basolateral and central amygdala have been shown to play important roles in addiction-related behavioral changes. Clinical and pre-clinical studies have characterized these brain regions and their corresponding neurochemical changes in numerous phases of drug dependence such as acute drug use, intoxication, craving, withdrawal, and relapse. At present, many studies have reported the individual effects of opioids and methamphetamine. However, little is known about their combined effects. Co-use of these drugs produces effects greater than either drug alone, where one decreases the side effects of the other, and the combination produces a prolonged intoxication period or a more desirable intoxication effect. An increasing number of studies have associated polydrug abuse with poorer treatment outcomes, drug-related deaths, and more severe psychopathologies. To date, the pharmacological treatment efficacy for polydrug abuse is vague, and still at the experimental stage. This present review discusses the human and animal behavioral, neuroanatomical, and neurochemical changes underlying both morphine and methamphetamine dependence separately, as well as its combination. This narrative review also delineates the recent advances in the pharmacotherapy of mono- and poly drug-use of opioids and methamphetamine at clinical and preclinical stages.

Opioid prescribing in out-of-hours primary care in Flanders and the Netherlands: A retrospective cross-sectional study

Background

Increased opioid prescribing has raised concern, as the benefits of pain relief not always outweigh the risks. Acute and chronic pain is often treated in a primary care out-of-hours (OOH) setting. This setting may be a driver of opioid use but the extent to which opioids are prescribed OOH is unknown. We aimed to investigate weak and strong opioid prescribing at OOH primary care services (PCS) in Flanders (Northern, Dutch-speaking part of Belgium) and the Netherlands between 2015 and 2019.

Methods

We performed a retrospective cross sectional study using data from routine electronic health records of OOH-PCSs in Flanders and the Netherlands (2015–2019). Our primary outcome was the opioid prescribing rate per 1000 OOH-contacts per year, in total and for strong (morphine, hydromorphone, oxycodone, oxycodone and naloxone, fentanyl, tapentadol, and buprenorphine and weak opioids (codeine combinations and tramadol and combinations) and type of opioids separately.

Results

Opioids were prescriped in approximately 2.5% of OOH-contacts in both Flanders and the Netherlands. In Flanders, OOH opioid prescribing went from 2.4% in 2015 to 2.1% in 2017 and then increased to 2.3% in 2019. In the Netherlands, opioid prescribing increased from 1.9% of OOH-contacts in 2015 to 2.4% in 2017 and slightly decreased thereafter to 2.1% of OOH-contacts. In 2019, in Flanders, strong opioids were prescribed in 8% of the OOH-contacts with an opioid prescription. In the Netherlands a strong opioid was prescribed in 57% of these OOH-contacts. Two thirds of strong opioids prescriptions in Flanders OOH were issued for patients over 75, in the Netherlands one third was prescribed to this age group.

Conclusion

We observed large differences in strong opioid prescribing at OOH-PCSs between Flanders and the Netherlands that are likely to be caused by differences in accessibility of secondary care, and possibly existing opioid prescribing habits. Measures to ensure judicious and evidence-based opioid prescribing need to be tailored to the organisation of the healthcare system.

Non-Peptide Opioids Differ in Effects on Mu-Opioid (MOP) and Serotonin 1A (5-HT1A) Receptors Heterodimerization and Cellular Effectors (Ca2+, ERK1/2 and p38) Activation

The importance of the dynamic interplay between the opioid and the serotonin neuromodulatory systems in chronic pain is well recognized. In this study, we investigated whether these two signalling pathways can be integrated at the single-cell level via direct interactions between the mu-opioid (MOP) and the serotonin 1A (5-HT1A) receptors. Using fluorescence cross-correlation spectroscopy (FCCS), a quantitative method with single-molecule sensitivity, we characterized in live cells MOP and 5-HT1A interactions and the effects of prolonged (18 h) exposure to selected non-peptide opioids: morphine, codeine, oxycodone and fentanyl, on the extent of these interactions. The results indicate that in the plasma membrane, MOP and 5-HT1A receptors form heterodimers that are characterized with an apparent dissociation constant Kdapp = (440 ± 70) nM). Prolonged exposure to all non-peptide opioids tested facilitated MOP and 5-HT1A heterodimerization and stabilized the heterodimer complexes, albeit to a different extent: Kd, Fentanylapp = (80 ± 70) nM), Kd,Morphineapp = (200 ± 70) nM, Kd, Codeineapp = (100 ± 70) nM and Kd, Oxycodoneapp = (200 ± 70) nM. The non-peptide opioids differed also in the extent to which they affected the mitogen-activated protein kinases (MAPKs) p38 and the extracellular signal-regulated kinase (Erk1/2), with morphine, codeine and fentanyl activating both pathways, whereas oxycodone activated p38 but not ERK1/2. Acute stimulation with different non-peptide opioids differently affected the intracellular Ca2+ levels and signalling dynamics. Hypothetically, targeting MOP−5-HT1A heterodimer formation could become a new strategy to counteract opioid induced hyperalgesia and help to preserve the analgesic effects of opioids in chronic pain.

Acupuncture therapy as an Evidence-Based Nonpharmacologic Strategy for Comprehensive Acute Pain Care: the Academic Consortium Pain Task Force White Paper Update

Background

A crisis in pain management persists, as does the epidemic of opioid overdose deaths, addiction, and diversion. Pain medicine is meeting these challenges by returning to its origins: the Bonica model of multidisciplinary pain care. The 2018 Academic Consortium White Paper detailed the historical context and magnitude of the pain crisis and the evidence base for nonpharmacologic strategies. More than 50% of chronic opioid use begins in the acute pain care setting. Acupuncture may be able to reduce this risk.

Objective

This article updates the evidence base for acupuncture therapy for acute pain with a review of systematic reviews and meta-analyses on postsurgical/perioperative pain with opioid sparing and acute nonsurgical/trauma pain, including acute pain in the emergency department.

Methods

To update reviews cited in the 2018 White Paper, electronic searches were conducted in PubMed, MEDLINE, CINAHL, and the Cochrane Central Register of Controlled Trials for “acupuncture” and “acupuncture therapy” and “acute pain,” “surgery,” “peri-operative,” “trauma,” “emergency department,” “urgent care,” “review(s) ,” “systematic review,” “meta-analysis,” with additional manual review of titles, links, and reference lists.

Results

There are 22 systematic reviews, 17 with meta-analyses of acupuncture in acute pain settings, and a review for acute pain in the intensive care unit. There are additional studies of acupuncture in acute pain settings.

Conclusion

The majority of reviews found acupuncture therapy to be an efficacious strategy for acute pain, with potential to avoid or reduce opioid reliance. Future multicenter trials are needed to clarify the dosage and generalizability of acupuncture for acute pain in the emergency department. With an extremely low risk profile, acupuncture therapy is an important strategy in comprehensive acute pain care.

Music-Induced Analgesia in Healthy Participants Is Associated With Expected Pain Levels but Not Opioid or Dopamine-Dependent Mechanisms

Music interventions accommodate the profound need for non-pharmacological pain treatment. The analgesic effect of listening to music has been widely demonstrated across studies. Yet, the specific mechanisms of action have still to be elucidated. Although the endogenous opioid and dopamine systems have been suggested to play an important role, a direct link has not been established. In addition, the involvement of placebo mechanisms is likely while largely unexplored. We examined the analgesic effect of music in healthy participants (n = 48) using a 3 × 3 within-subjects design with pharmacological manipulations and a matched, auditory control for music. Participants were exposed to thermal pain stimuli while listening to three auditory excerpts: music (active condition), nature sound (matched, auditory contextual condition), and noise (neutral control condition). The participants rated their expected and perceived pain levels in relation to each of the auditory excerpts. To investigate the involvement of the endogenous opioid and dopamine systems, the test session was performed three times on separate days featuring a double-blind randomized oral administration of naltrexone (opioid antagonist), haloperidol (dopamine antagonist), and an inactive agent (control). Our results support an analgesic effect of music. Contrary to current hypotheses, neither of the antagonists attenuated the effect of music. Yet, the participants' expectations for pain relief predicted their perceived pain levels during the auditory excerpts—even when controlling for a gradual learning effect. In conclusion, we demonstrate that the analgesic effect of music is at least partially mediated by expectations of an analgesic effect—a core mechanism in placebo effects—but not by opioid and dopamine-dependent mechanisms.

Lack of Neuromodulation Knowledge Among Rural Family Medicine Residents: A Call for Implementation Research

Objective

Spinal cord stimulation is a proven, evidence-based therapy for persistent spinal pain syndrome. While some patients with this disease are managed by chronic pain physicians, many are managed in primary care offices. Despite mounting evidence, dissemination of this research outside of neuromodulation related fields and implementation of this treatment in common practice has not yet occurred. We hypothesize that family medicine residents in rural training programs will have little knowledge of neuromodulation despite it being an evidence-based and common treatment of post-laminectomy syndrome.

Materials and Methods

Online surveys were sent to family medicine residents in six rural family medicine training programs at the University of Arkansas for Medical Sciences Regional Programs to characterize knowledge of neuromodulation as a treatment for post-laminectomy syndrome.

Results

Forty-one percent of responding rural, Arkansas family medicine residents reported treating post-laminectomy syndrome during their training, yet only 10% have referred a patient for neuromodulation consultation. Residents rated their knowledge of neuromodulation/spinal cord stimulation at 19 on a scale of 0 (no knowledge) to 100 (extensive knowledge).

Conclusion

Despite proof that neuromodulation is an evidence-based treatment for post-laminectomy/failed back syndrome, rural family medicine residents have limited knowledge about the therapy and many do not consider a referral for neuromodulation. Further research to ascertain effective implementation strategies to increase the uptake of neuromodulation for patients with post-laminectomy syndrome is desperately needed.

Classification of Patients for Whom Benefit of Long-term Opioid Therapy No Longer Outweighs Harm: Protocol for a Delphi Study

Background

Patients with chronic pain prescribed long-term opioid therapy may come to a point where the benefits of the therapy are outweighed by the risks and tapering is indicated. At the 2019 Veterans Health Administration State of the Art Conference, there was an acknowledgment of a lack of clinical guidance with regard to treating this subset of patients. Some of the participants believed clinicians and patients would both benefit from a new diagnostic entity describing this situation.

Objective

The aim of this study was to determine if a new diagnostic entity was needed and what the criteria of the diagnostic entity would be. Given the ability of the Delphi method to synthesize input from a broad range of experts, we felt this technique was the most appropriate for this study.

Methods

We designed a modified Delphi technique involving 3 rounds. The first round is a series of open-ended questions asking about the necessity of this diagnostic entity, how this condition is different from opioid use disorder, and what its possible diagnostic criteria would be. After synthesizing the responses collected, a second round will be conducted to ask participants to rate the different responses offered by their peers. These ratings will be collected and analyzed, and will generate a preliminary definition for this clinical phenomena. In the third round, we will circulate this definition with the aim of achieving consensus.

Results

The modified Delphi study was initiated in July of 2020 and analysis is currently underway.

Conclusions

This protocol has been approved by the Internal Review Board at the Connecticut Veterans Affairs and the study is in process. This protocol may assist other researchers conducting similar studies.

International Registered Report Identifier (IRRID)

DERR1-10.2196/33310

Clinical implications of opioid-induced ventilatory impairment

Opioid-induced ventilatory impairment is the primary mechanism of harm from opioid use. Opioids suppress the activity of the central respiratory centres and are sedating, leading to impairment of alveolar ventilation.Respiratory physiological changes induced with acute opioid use include depression of the hypercapnic ventilatory response and hypoxic ventilatory response. In chronic opioid use a compensatory increase in hypoxic ventilatory response maintains ventilation and contributes to the onset of sleep-disordered breathing patterns of central sleep apnoea and ataxic breathing. Supplemental oxygen use in those at risk of opioid-induced ventilatory impairment requires careful consideration by the clinician to prevent failure to detect hypoventilation, if oximetry is being relied on, and the overriding of hypoxic ventilatory drive. Obstructive sleep apnoea and opioid-induced ventilatory impairment are frequently associated, with this interrelationship being complex and often unpredictable. Monitoring the patient for opioid-induced ventilatory impairment poses challenges in the areas of reliability, avoidance of alarm fatigue, cost, and personnel demands. Many situations remain in which patients cannot be provided effective analgesia without opioids, and for these the clinician requires a comprehensive knowledge of opioid-induced ventilatory impairment.

Opioids in acute pain: Towards getting the right balance

Misuse of prescription opioids forced an inevitable response from authorities to intervene with consequences felt by all.In the Australian community one person will die for approximately every 3600 adults prescribed opioids, while in the hospital setting a postoperative patient managed primarily with opioids, as opposed to epidural analgesia, has an additional risk of death as high as between one in 56 to 477.Opioids maintain a valid role in acute pain management when use is reasoned and with full awareness of the harms and how they are to be avoided, such as in those at risk of ongoing use, the opioid naïve, and when opioid-induced ventilatory impairment may occur.Clinicians managing acute pain can focus on assessing pain versus nociception, strategically apply antinociceptive medications and neural blockade when indicated, assess pain with an emphasis on the degree of bothersomeness and functional impairment and, finally, optimise the use of framing and placebo-enhancing communication to minimise reliance on medications.

Melatonin attenuates morphine-induced conditioned place preference in Wistar rats

PURPOSE

Morphine is the predominantly used drug for postoperative and cancer pain management. However, the abuse potential of morphine is the primary disadvantage of using opioids in pain management. Melatonin is a neurohormone synthesized in the pineal gland and is involved in circadian rhythms in mammals, as well as other physiological functions. Melatonin provenly attenuates alcohol-seeking and relapse behaviors in rats. Therefore, we aimed to investigate the involvement of the melatonergic system in attenuating morphine dependence.

MATERIALS AND METHODS

Male Wistar rats were divided into three groups: control, morphine, and morphine + melatonin. Animals were habituated for 3 days, and the initial preference was evaluated. Following the initial preference, the control group received the vehicle and was placed for a 45-min session in the assigned chamber every day, alternating between the two chambers, for 8 days. The morphine group received a morphine injection (5 mg/kg, IP) and was placed for a 45-min session in the white chamber, for a total of four sessions. The morphine + melatonin group received the morphine injection (5 mg/kg, IP) for a total of four sessions over an 8-day period. In the posttest session, the control and morphine groups received a vehicle injection 30 min before placement in the conditioned place preference (CPP). The morphine + melatonin group received a single injection of melatonin (50 mg/kg, IP) 30 min before the preference test.

RESULTS

Statistical analysis revealed that repeated administration of morphine for four sessions produced a significant increase in the CPP score in the morphine group compared to the control group. However, a single melatonin injection administered 30 min before the posttest attenuated morphine-seeking behavior and reduced morphine-induced place preference.

CONCLUSION

These findings provide novel evidence for the role of the melatonergic system as a potential target in modulating morphine-seeking behavior.

Recommendations for Preventing Medication Diversion and Misuse in Hospice Care: A Modified Delphi Study

CONTEXT

Recommendations are needed to help minimize the risks of medication diversion and misuse in the hospice setting.

OBJECTIVE

To identify recommendations that could help prevent medication diversion and misuse in hospice care.

METHODS

A modified Delphi method was utilized. An interdisciplinary panel of ten experts engaged in three phases of online and in-person voting regarding recommendations. Consensus for recommendations required a minimum of 80% endorsement by the panel experts. After two rounds of voting and several rounds of informal voting, 15 total recommendations were endorsed.

RESULTS

Fifteen recommendations achieved at least 80% endorsement during the final round of voting. Each of the following recommendation topics received ≥ 80% endorsement, the need to balance prevention efforts with quality care, screening clinical job candidates, family education and screening, medication monitoring, responding to missing/diverted medications, and medication disposal. Panelists rated the Patient & Family Education recommendation as most important (M = 9.7; SD = 0.7) followed closely by Responding to Medication Diversion or Misuse (M = 9.5; SD = 1.1).

CONCLUSION

These recommendations were created by experts in the field to reduce the risk of medication diversion and misuse. Further steps towards implementation may appropriately reduce these risks.

Older, Male Orthopaedic Surgeons From Southern Geographies Prescribe Higher Doses of Post-Operative Narcotics Than do their Counterparts: A Medicare Population Study

Purpose

Methods

Results

Conclusion

Level of Evidence

Physical work conditions and disparities in later life functioning: Potential pathways

Research in the US on the social determinants of reduced physical functioning at older ages has typically not considered physical work conditions as contributors to disparities. We briefly describe a model of occupational stratification and segregation, review and synthesize the occupational health literature, and outline the physiological pathways through which physical work exposures may be tied to long-term declines in physical functioning. The literature suggests that posture, force, vibration, and repetition are the primary occupational risk factors implicated in the development of musculoskeletal disorders, through either acute injuries or longer-term wear and tear. Personal risk factors and environmental and structural work characteristics can modify this association. In the long-term, these musculoskeletal disorders can become chronic and ultimately lead to functional limitations and disabilities that interfere with one's quality of life and ability to remain independent. We then use data on occupational characteristics from the Occupational Information Network (O*NET) linked to the 2019 American Community Survey (ACS) to examine disparities among sociodemographic groups in exposure to these risk factors. Occupations with high levels of these physical demands are not limited to those traditionally thought of as manual or blue-collar jobs and include many positions in the service sector. We document a steep education gradient with less educated workers experiencing far greater physical demands at work than more educated workers. There are pronounced racial and ethnic differences in these exposures with Hispanic, Black, and Native American workers experiencing higher risks than White and Asian workers. Occupations with high exposures to these physical risk factors provide lower compensation and are less likely to provide employer-sponsored health insurance, making it more difficult for workers to address injuries or conditions that arise from their jobs. In sum, we argue that physical work exposures are likely an important pathway through which disparities in physical functioning arise.

Effects of COVID-19 Social Distancing Measures in Individuals with Chronic Pain Living in Spain in the Late Stages of the Lockdown

Social distancing measures during the lockdown have had a negative impact on chronic pain patients' function. Research, however, has only focused on the early stages of the first lockdowns. The aim of this study was to improve the understanding of the effects of COVID-19 social distancing measures on individuals with chronic pain living in Spain during the late stages of the lockdown. A group of 361 adults with pain participated in this study. They responded to an online survey and provided information on sociodemographic issues, pain, fatigue, perceived health, and quality of life. The data showed that most participants suffered moderate to severe pain and interferences with pain treatment and an increase in pain intensity during the lockdown. Most participants also informed us that fatigue had worsened during the lockdown (62%). Importantly, females with lower monthly family income and lower education have been found to be associated with greater levels of pain and fatigue. Despite this, participants perceived themselves as having good health and good quality of life. The findings from this study can be used to inform policy and specific responses for future COVID-19 waves and future pandemics where social distancing measures must be implemented.

Comprehensive pain management as a frontline treatment to address the opioid crisis

BACKGROUND

The opioid crisis continues to devastate individuals and communities in the United States and abroad. While there have been several measures to address the over-prescription of opioid analgesics, the number of overdose deaths related to prescription opioids has not changed appreciably in the last 10 years. Comprehensive (or multidisciplinary) pain recovery programs consist of providers from multiple backgrounds that treat pain on an individual level through a combination of approaches including physical therapy, emotional and spiritual support, cognitive behavioral therapy, and non-opioid pharmacotherapies. Because there is a dynamic interplay between a given chronic pain patient and multiple providers, comprehensive pain programs are not as "standardized" as other medical treatments because they are meant to meet the individual needs of each patient and their specific pain diagnoses Methods: Review of the literature.

RESULTS

There is evidence that comprehensive pain treatment can reduce pain severity and improve functioning; comprehensive pain treatment can be used to treat those with post-surgical pain, thus preventing the onset of non-medical opioid use and opioid use disorder, and in persons with chronic pain who are on long-term opioid therapy, as a method to reduce or eliminate opioid medication use. Comprehensive pain recovery programs were abundant for a period from the 1960s through the 1980s, but for a variety of reasons, they became financially unsustainable as the national reimbursement environment evolved.

CONCLUSIONS

In the context of the protracted and deadly opioid crisis, revitalizing and expanding comprehensive pain treatment should be considered as a frontline approach to treat chronic pain.

An Audio-Recorded Hypnosis Intervention for Chronic Pain Management in Cancer Survivors: A Randomized Controlled Pilot Study

This pilot study evaluated the feasibility, acceptability, and potential efficacy of a 4-week hypnosis audio-recording intervention in cancer survivors with chronic pain. Forty participants were randomly assigned to treatment (n = 21) or wait-list (n = 19) conditions. Pain intensity ratings were lower at Week 4 for both groups. The effect size for pain reduction in the treatment group was d = 0.25 from baseline to 4 weeks, and the interaction effect (Time x Group) was F = .024; η²_p = .001. The small interaction effect may be due to the availability of only one recording and large variability in dose. Qualitative data indicated that the intervention's benefits included participation in self-care, improved relaxation, and an opportunity to focus on oneself in a positive way. Further efficacy testing of an audio-recording intervention in a fully powered clinical trial is warranted.

A Clinical Description of Chronic Pain in a General Population Using ICD-10 and ICD-11 (The HUNT Pain Examination Study)

The purpose was to present a total description, distribution, and ranking of chronic pain conditions in the general population. This was based on structured clinical examinations of a random sample from a population-based survey (HUNT3) with a calculated oversampling of participants with chronic pain. Supplemented with access to hospital reports, the examination was performed by experienced physicians and psychologists using a consistent definition of chronic pain as well as ICD-10- and the new ICD-11-classification. The main findings were that a higher proportion of the 551 participants had chronic pain assessed by clinical examination (399) than by self-report in a survey the same day (337). Among those with examination-verified chronic pain estimated from HUNT3 to represent 27.9% of the general population, 63% had chronic primary pain, 81% musculoskeletal pain, and 77% more than one chronic pain condition. When separating chronic primary from chronic secondary pain according to ICD-11, the weighted prevalence was 17.7% for chronic pain conditions of unknown and 10.2% of known cause. When all the participants' conditions were accounted for, the most prevalent was nonspecific low back (10.8%) and neck pain (7.6%). Participants with chronic primary pain did not have significantly more psychopathology than those with chronic secondary pain: 14.5% versus 12.5%. Perspective: Since this study confirms the high prevalence in self-report surveys and indicates that two thirds of chronic pain conditions cannot be explained by underlying diseases, this huge health and societal problem should be solved primarily on a public health level directed toward prevention and rehabilitation.

Patterns, trends and determinants of medical opioid utilization in Canada 2005-2020: characterizing an era of intensive rise and fall

BACKGROUND

Into the 21st century, the conflation of high rates of chronic pain, systemic gaps in treatment availability and access, and the arrival of potent new opioid medications (e.g., slow-release oxycodone) facilitated strong increases in medical opioid dispensing in Canada. These persisted until post-2010 alongside rising opioid-related adverse (e.g., morbidity/mortality) outcomes. We examine patterns, trends and determinants of opioid dispensing in Canada, and specifically its 10 provinces, for the years 2005-2020.

METHODS

Raw data on prescription opioid dispensing were obtained from a large national community-based pharmacy database (IQVIA/Compuscript), converted into Defined-Daily-Doses/1,000 population/day for 'strong' and 'weak' opioid categories per standard methods. Dispensing by opioid category and formulations by province/year was assessed descriptively; regression analysis was applied to examine possible segmentation of over-time strong opioid dispensing.

RESULTS

All provinces reported starkly increasing strong opioid dispensing peaking 2011-2016, and subsequent marked declines. About half reported lower strong opioid dispensing in 2020 compared to 2005, with continuous inter-provincial differences of > 100 %; weak opioids also declined post-2011/12. Segmented regression suggests breakpoints for strong opioids in 2011/12 and 2015/16, coinciding with main interventions (e.g., selective opioid delisting, new prescribing guidelines) towards more restrictive opioid utilization control.

CONCLUSIONS

We characterized an era of marked rise and fall, while featuring stark inter-provincial heterogeneity in opioid dispensing in Canada. While little evidence for improvements in pain care outcomes exists, the starkly inverting opioid utilization have been associated with extensive population-level harms (e.g., misuse, morbidity, mortality) over-time. This national case study raises fundamental questions for opioid-related health policy and practice.