Opioids and Chronic Pain: An Analytic Review of the Clinical Evidence

Transforming Growth Factor-β-Activated Kinase 1 (TAK1) Alleviates Inflammatory Joint Pain in Osteoarthritis and Gouty Arthritis Preclinical Models

Purpose

Joint pain is one of the most commonly reported pain types in the United States. In the case of patients suffering from inflammatory diseases such as osteoarthritis (OA) and gout, persistent inflammation due to long-term overexpression of several key cytokines has been linked to neuronal hypersensitivity and damage within the joints. Ultimately, a subset of patients develop chronic pain. Pharmacologic treatment of joint pain involves the use of analgesics such as acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs), opioids, antidepressants, as well as intra-articular injections of corticosteroids and hyaluronic acid. However, NSAIDs are short-acting and fail to alleviate severe pain, opioids are generally ineffective at managing chronic pain, and all therapeutic options involve increased risks of serious side effects.

Methods

We explored the therapeutic and analgesic effects of transforming growth factor-β-activated kinase 1 (TAK1) inhibition in both the monoiodoacetate (MIA) and monosodium urate (MSU) models of joint pain as an innovative strategy for alleviating chronic inflammatory pain. Mechanical allodynia (Von Frey), weight-bearing and histological changes were measured in separate groups of rats receiving either the selective TAK1 inhibitor, HS-276, gabapentin or vehicle.

Results

Our data support that TAK1 inhibition effectively prevented the development of mechanical allodynia and differential weight-bearing in the MIA model. In the MSU model of gouty arthritis, treatment with HS-276 significantly reduced mechanical allodynia and knee edema in female rats, but not male rats. Histological evaluation of effected joints in both models showed that HS-276 treatment significantly reduced disease-induced degradation of the joint.

Conclusion

Our results support that TAK1 is a critical signaling node in inflammatory joint diseases such as OA and gouty arthritis. Selective pharmacological inhibition significantly attenuated several aspects of the disease, including joint degeneration and mechanical pain. Thus, TAK1 is a novel therapeutic target for the treatment of painful inflammatory joint diseases.

Perspective

This article reports on the therapeutic potential of TAK1 in the treatment of chronic inflammatory joint diseases such as OA and gout. Using the selective TAK1 inhibitor, HS-276, we show the therapeutic and analgesic effects of TAK1 inhibition in two preclinical murine models of inflammatory joint pain.

Posttraumatic Stress and Opioid Use and Pain among Individuals with Probable Posttraumatic Stress Disorder and Self-Reported Chronic Pain: The Role of Health Literacy

BACKGROUND

Chronic pain and opioid misuse are a prevalent comorbidity with deleterious health outcomes. Growing work indicates that posttraumatic stress disorder (PTSD) can increase the risk for chronic pain and opioid misuse and dependence. However, there is little understanding of social determinants of health (SDoH) that may account for interrelations of PTSD with chronic pain and opioid misuse and dependence. Health literacy is one relevant SDoH construct, reflecting the ability to gather, process, and comprehend health-related information required to engage in a healthcare setting.

OBJECTIVE

The purpose of the present cross-sectional study was to examine the indirect effect of health literacy in the association between PTSD and opioid misuse, opioid dependence, pain intensity, and pain disability.

METHOD

The sample included 142 adults (Mage = 35.2, SD = 9.9; 67.4% female; 70.1% White/Caucasian) with self-reported chronic pain and probable PTSD who were using opioid medication.

RESULTS

Results demonstrated that PTSD symptom severity had a small indirect effect on opioid misuse and opioid dependence via health literacy; no indirect effects were evident for pain intensity and disability.

CONCLUSION

The present investigation provides evidence that health literacy may serve as an important explanatory factor in associations between PTSD symptom severity and opioid misuse and dependence among adults with co-occurring probable PTSD and chronic pain.

The Role and Applications of Artificial Intelligence in the Treatment of Chronic Pain

PURPOSE OF REVIEW

This review aims to explore the interface between artificial intelligence (AI) and chronic pain, seeking to identify areas of focus for enhancing current treatments and yielding novel therapies.

RECENT FINDINGS

In the United States, the prevalence of chronic pain is estimated to be upwards of 40%. Its impact extends to increased healthcare costs, reduced economic productivity, and strain on healthcare resources. Addressing this condition is particularly challenging due to its complexity and the significant variability in how patients respond to treatment. Current options often struggle to provide long-term relief, with their benefits rarely outweighing the risks, such as dependency or other side effects. Currently, AI has impacted four key areas of chronic pain treatment and research: (1) predicting outcomes based on clinical information; (2) extracting features from text, specifically clinical notes; (3) modeling 'omic data to identify meaningful patient subgroups with potential for personalized treatments and improved understanding of disease processes; and (4) disentangling complex neuronal signals responsible for pain, which current therapies attempt to modulate. As AI advances, leveraging state-of-the-art architectures will be essential for improving chronic pain treatment. Current efforts aim to extract meaningful representations from complex data, paving the way for personalized medicine. The identification of unique patient subgroups should reveal targets for tailored chronic pain treatments. Moreover, enhancing current treatment approaches is achievable by gaining a more profound understanding of patient physiology and responses. This can be realized by leveraging AI on the increasing volume of data linked to chronic pain.

Ethical considerations and decision making in opioid prescribing for chronic pain: A case study in rheumatology practice

ABSTRACT

Dilemmas regarding opioid prescribing for chronic pain frequently occur within health care settings. The ethical principles of autonomy, beneficence, nonmaleficence, and justice, as well as the principles of care ethics, can assist in addressing these opioid-related dilemmas. The purpose of this clinical case study is to provide a case study highlighting an opioid prescribing dilemma and then identify opioid-related transition considerations; address ethical questions that nurse practitioners (NPs) may encounter in clinical practice when providing care for individuals living with chronic pain who may need or use a prescribed opioid medication; and draw on the ethical principles and care ethics to provide guidance for NPs who face these challenging issues.

Preoperative opioid use is associated with worse preoperative patient-reported outcomes in hip arthroscopy patients

OBJECTIVES

The purpose of this study was to define the rate of preoperative opioid use among patients undergoing hip arthroscopy, ascertain which clinical factors are associated with opioid use, and assess the effect of preoperative opioid usage on preoperative patient-reported outcome (PRO) measures.

METHODS

A single institution orthopedic registry was retrospectively analyzed for patients undergoing hip arthroscopy for femoroacetabular impingement (FAI) syndrome with or without labral tear between 2015 and 2022. Patients completed Patient-Reported Outcomes Measurement Information System (PROMIS) in six domains, Numeric Pain Scores (NPS), and Musculoskeletal Outcomes Data Evaluation and Management System expectations domain preoperatively. Patients' charts were reviewed to determine demographic factors and identify any active opioid prescription within 6 weeks before surgery. Bivariate analysis was used to determine associations between preoperative opioid use and baseline PROs. Statistically significant bivariate associations were further tested by multivariate analysis to determine independent predictors.

RESULTS

A total of 123 patients were included (age 39.7 ​± ​12.0 years; 87 females; body mass index 27.4 ​± ​5.7 kg/m2). There were 21 patients (17%) using opioids preoperatively. Prior orthopedic or other surgery and lower education level were associated with preoperative opioid use. Patients with preoperative opioid use scored statistically significantly worse compared with those without preoperative opioid use on baseline PROMIS Physical Function (38.6 vs 40.5, p ​= ​0.01), Pain Interference (65.9 vs 60.2, p ​= ​0.001), Fatigue (60.7 vs 51.6, p ​= ​0.005), Social Satisfaction (38.2 vs 43.2, p ​= ​0.007), and Depression (54.2 vs 48.8, p ​= ​0.01). Preoperative opioid use was also associated with statistically significantly worse preoperative NPS for both the operative hip (6.3 vs 4.6, p ​= ​0.003) and whole body (3.0 vs 1.4, p ​= ​0.008). Preoperative opioid use was an independent predictor of worse baseline PROMIS Pain Interference, Fatigue, Social Satisfaction, and NPS for the operative hip.

CONCLUSION

Patients using opioids preoperatively had worse baseline PROs for physical function, pain, social satisfaction, and depression than those not using opioids preoperatively. When controlling for confounding variables, preoperative opioid use was independently predictive of worse baseline pain, fatigue, and social satisfaction.

LEVEL OF EVIDENCE

Level III, prognostic study.

Gut dysbiosis was inevitable, but tolerance was not: temporal responses of the murine microbiota that maintain its capacity for butyrate production correlate with sustained antinociception to chronic voluntary morphine

The therapeutic benefits of opioids are compromised by the development of analgesic tolerance, which necessitates higher dosing for pain management thereby increasing the liability for dependence and addiction. Rodent models indicate opposing roles of the gut microbiota in tolerance: morphine-induced gut dysbiosis exacerbates tolerance, whereas probiotics ameliorate tolerance. Not all individuals develop tolerance which could be influenced by differences in microbiota, and yet no study has capitalized upon this natural variation to identify specific features linked to tolerance. We leveraged this natural variation in a murine model of voluntary oral morphine self-administration to elucidate the mechanisms by which microbiota influences tolerance. Although all mice shared similar and predictive morphine-driven microbiota changes that largely masked informative associations with variability in tolerance, our high-resolution temporal analyses revealed a divergence in the progression of dysbiosis that best explained differences in the development in tolerance. Mice that did not develop tolerance also maintained a higher abundance of taxa capable of producing the short-chain fatty acid (SCFA) butyrate, known to bolster intestinal barriers, suppress inflammation, and promote neuronal homeostasis. Furthermore, dietary butyrate supplementation significantly reduced the development of tolerance. These findings could inform immediate therapies to extend the analgesic efficacy of opioids.

Telling the story of the opioid crisis: A narrative analysis of the TV series Dopesick

Dopesick (2021) is the first TV series whose plot deals exclusively with the opioid crisis in the United States. The current study uses narrative analysis and framing theory to explore this series, discussing its portrayal of the people and themes involved in the opioid crisis. Our analysis found that although Dopesick attempts to portray multiple dimensions of the opioid crisis, its narrative oversimplifies the story in attributing the cause of the problem almost exclusively to Purdue Pharma and its director Richard Sackler, while downplaying other factors that contributed to the opioid crisis. Thus, the narrative in this TV series tends to offer simple explanations to a complex problem for which simple solutions are likely to be inadequate.

Association of chronic pain with suicide attempt and death by suicide: a two-sample Mendelian randomization

Prior studies have suggested an association between chronic pain and suicidal behavior. However, evidence supporting the causal nature of this association, and the role played by depression, remain difficult to establish due to confounding. We investigated associations of chronic pain with suicide attempt and death by suicide as well as the mediating role of depression in this association using a genetically informed method strengthening causal inference. We conducted a two-sample Mendelian randomization. Independent SNPs (N = 97) from the multisite chronic pain GWAS (NGWAS = 387,649) were used as instrumental variables to test associations of chronic pain with suicide attempt (measured from hospital records; NGWAS = 50,264) and death by suicide (measured from official death causes; NGWAS = 18,085). Indirect associations of chronic pain with suicide attempt and death by suicide via major depressive disorder (NGWAS = 173,005) were estimated. Primary analyses were supported by a range of sensitivity and outlier analyses. We found evidence supporting the contribution of chronic pain to increasing the risk of suicide attempt (OR = 1.67, CI = 1.21-2.35) and death by suicide (OR = 2.00, CI = 1.10-3.62). Associations were consistent across sensitivity analysis methods, and no evidence for outliers driving these associations was found. Through mediation analyses, we found that major depressive disorder explained a substantial proportion of the association between chronic pain and suicide attempt (proportion mediated = 39%; ORindirect association = 1.32, CI = 1.09-1.61) and death by suicide (proportion mediated = 34%; ORindirect association = 1.40, CI = 1.13-1.73). Our findings suggest that both pain management interventions and prevention of depression are likely to be effective strategies to reduce suicide risk in individuals with chronic pain.

Efficacy of virtual reality for pain relief in medical procedures: a systematic review and meta-analysis

BACKGROUND

Effective pain control is crucial to optimise the success of medical procedures. Immersive virtual reality (VR) technology could offer an effective non-invasive, non-pharmacological option to distract patients and reduce their experience of pain. We aimed to evaluate the efficacy of Immersive virtual reality (VR) technology in reducing patient's pain perception during various medical procedures by conducting a systematic review and meta-analysis.

METHODS

We searched MEDLINE, EMBASE, CENTRAL, CINAHL, and SIGLE until December 2022 for all randomised clinical trials (RCT) evaluating any type of VR in patients undergoing any medical procedure. We conducted a random effect meta-analysis summarising standardised mean differences (SMD) with 95% confidence intervals (CI). We evaluated heterogeneity using I 2 and explored it using subgroup and meta-regression analyses.

RESULTS

In total, we included 92 RCTs (n = 7133 participants). There was a significant reduction in pain scores with VR across all medical procedures (n = 83, SMD - 0.78, 95% CI - 1.00 to - 0.57, I 2 = 93%, p = < 0.01). Subgroup analysis showed varied reduction in pain scores across trial designs [crossover (n = 13, SMD - 0.86, 95% CI - 1.23 to - 0.49, I 2 = 72%, p = < 0.01) vs parallel RCTs (n = 70, SMD - 0.77, 95% CI - 1.01 to - 0.52, I 2 = 90%, p = < 0.01)]; participant age groups [paediatric (n = 43, SMD - 0.91, 95% CI - 1.26 to - 0.56, I 2 = 87%, p = < 0.01) vs adults (n = 40, SMD - 0.66, 95% CI - 0.94 to - 0.39, I 2 = 89%, p = < 0.01)] or procedures [venepuncture (n = 32, SMD - 0.99, 95% CI - 1.52 to - 0.46, I 2 = 90%, p = < 0.01) vs childbirth (n = 7, SMD - 0.99, 95% CI - 1.59 to - 0.38, I 2 = 88%, p = < 0.01) vs minimally invasive medical procedures (n = 25, SMD - 0.51, 95% CI - 0.79 to - 0.23, I 2 = 85%, p = < 0.01) vs dressing changes in burn patients (n = 19, SMD - 0.8, 95% CI - 1.16 to - 0.45, I 2 = 87%, p = < 0.01)]. We explored heterogeneity using meta-regression which showed no significant impact of different covariates including crossover trials (p = 0.53), minimally invasive procedures (p = 0.37), and among paediatric participants (p = 0.27). Cumulative meta-analysis showed no change in overall effect estimates with the additional RCTs since 2018.

CONCLUSIONS

Immersive VR technology offers effective pain control across various medical procedures, albeit statistical heterogeneity. Further research is needed to inform the safe adoption of this technology across different medical disciplines.

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.

Developing mathematical models to compare and analyse the pharmacokinetics of morphine and fentanyl

Background and Aims

The two-compartment model is generally used in pharmacokinetics to illustrate the distribution and excretion of drugs. In this study, we evaluated the distribution patterns of morphine and fentanyl by using a two-compartment model.

Methods

Using numeric analysis techniques, non-linear ordinary differential equations were used to mathematically analyse drug distribution, transition, and concentration in the body compartments. Math Works, Inc., MATLAB, version 2023a, a programming tool, was used to characterise the impact of initial concentration and rate constants on the kinetics of the drug. For a definite therapeutic concentration of morphine and fentanyl in blood, pharmacokinetic characteristics were plotted.

Results

The study results showed the time taken by morphine and fentanyl to reach a target concentration in the blood that is sufficient to generate the preferred therapeutic effects. The mathematical models comparing morphine and fentanyl pharmacokinetics showed that fentanyl reached the target therapeutic concentration 125 minutes earlier than morphine and was metabolised and removed from the body more rapidly (44 minutes earlier than morphine).

Conclusion

These comparative mathematical models on morphine and fentanyl enable the determination of drug dosages and understanding of drug efficacy that facilitates optimising dosing regimens. The right choice between them can be made based on the time to reach the target therapeutic concentration in the blood, elimination time, severity of pain, and patient characteristics.

Predictors and Consequences of Cancer and Non-Cancer-Related Pain in Those Diagnosed with Primary and Metastatic Cancers

OBJECTIVES

The aims of the study were to (1) describe types of pain in cancer patients, (2) examine the predictors and consequences of pain, (3) investigate the association between type of pain and survival, and (4) examine potential biological mediators of pain and survival.

METHODS

This was a secondary analysis of baseline data from patients diagnosed with cancer. Patients answered questionnaires that assessed sociodemographic characteristics, pain, depression, sleep, and fatigue. Blood was collected and cytokine assays were performed. Analysis of variance, Kaplan-Meier, and Cox regression survival analyses were used to test the aims.

RESULTS

Of the 779 patients diagnosed with cancer, the mean age was 63.5 years, 57.8% male, and 90.6% White. Of those who reported pain (total 70.3%), 46.5% stated their pain was cancer-related while 53.5% stated their pain was non-cancer-related. While both cancer and non-cancer-related pain was associated with depressive symptoms, fatigue, and sleep duration, those with cancer-related pain had significantly higher rates of depressive symptoms (F(1,516) = 21.217, p < 0.001) and fatigue (F(1,516) = 30.973, p < 0.001) but not poorer sleep (F(1,497) = 0.597, p = 0.440). After adjusting for sociodemographic, disease-related characteristics, depression, sleep duration, and morphine milligram equivalent, patient reports of cancer-related pain were significantly associated with poorer survival (HR = 0.646, 95% CI = 0.459-0.910, p = 0.012) compared to those with non-cancer-related pain, which was not associated with survival (HR = 1.022, 95% CI = 0.737-1.418, p = 0.896). Cytokines did not significantly mediate the link between pain and survival.

CONCLUSION

While nearly half of the pain reported was cancer-related, both types of pain resulted in greater symptom burden, but only cancer-related pain was associated with survival.

Sensory stimulations potentializing digital therapeutics pain control

For the past two decades, using Digital Therapeutics (DTx) to counter painful symptoms has emerged as a novel pain relief strategy. Several studies report that DTx significantly diminish pain while compensating for the limitations of pharmacological analgesics (e.g., addiction, side effects). Virtual reality (VR) is a major component of the most effective DTx for pain reduction. Notably, various stimuli (e.g., auditory, visual) appear to be frequently associated with VR in DTx. This review aims to compare the hypoalgesic power of specific stimuli with or without a VR environment. First, this review will briefly describe VR technology and known elements related to its hypoalgesic effect. Second, it will non-exhaustively list various stimuli known to have a hypoalgesic effect on pain independent of the immersive environment. Finally, this review will focus on studies that investigate a possible potentialized effect on pain reduction of these stimuli in a VR environment.

Answering Big Questions in Pain Medicine

The future of pain medicine is marked by many questions. What can other nations around the world learn from the opioid crisis that is still affecting the United States? The American opioid experience was mischaracterized and wrongly described, and its causes were misdiagnosed from the outset, leading to its mismanagement and the abandonment of many chronic pain patients to their suffering. There are a few new drugs in the analgesic armamentarium. What new targets do we have in pain medicine? There are many breakthroughs, discoveries, and potential new targets that could add to our analgesic prescribing choices. These include sigma receptors, d-amino acid oxidase, endoplasmic reticulum stress receptors, histone deacetylase, and others. Neuromodulation had been used with varying degrees of success for years, but with a simplistic approach based on the gate theory of pain. Despite our familiarity with neuromodulation and spinal cord stimulators, neuromodulation research indicates that the activation of glial cells may activate the immune system and enhance analgesia. Neuromodulation studies have concentrated on how electricity affects neuronal activity rather than how electrical activity could reduce pain. There are still more frontiers in our battle against pain and some promising avenues for treatments. This narrative review will try to summarize what can be done from the perspective of recent technological and pharmacological developments.

Arnold-Chiari Malformations in Pregnancy and Labor: Challenges and Management Strategies

Arnold-Chiari malformations (ACMs) present unique challenges in pregnancy and labor, requiring a comprehensive understanding and multidisciplinary approach to care. This review article provides an overview of ACMs, including their definition, classification, and prevalence. The challenges in diagnosing ACMs during pregnancy, the available imaging modalities, and screening recommendations are discussed. The impact of ACMs on maternal health, fetal development, and the management strategies employed during pregnancy and labor are explored. Emphasis is placed on the importance of a multidisciplinary approach involving neurologists, obstetricians, and other specialists. Medical management options for symptom relief, surgical interventions, and anesthetic considerations during labor and delivery are also addressed. The importance of postpartum care, breastfeeding considerations, and long-term follow-up for women with ACMs who desire future pregnancies are highlighted. Finally, areas for further research and advancements in ACM management are identified. By improving our understanding and management of ACMs in pregnancy and labor, healthcare professionals can optimize care and improve outcomes for mothers and babies affected by this condition.

I Feel! Therefore, I Am from Pain to Consciousness in DOC Patients

Pain assessment and management in patients with disorders of consciousness (DOC) is a challenging and important aspect of care, with implications for detecting consciousness and promoting recovery. This narrative review explores the role of pain in consciousness, the challenges of pain assessment, pharmacological treatment in DOC, and the implications of pain assessment when detecting changes in consciousness. The review discusses the Nociception Coma Scale and its revised version, which are behavioral scales used to assess pain in DOC patients, and the challenges and controversies surrounding the appropriate pharmacological treatment of pain in these patients. Moreover, we highlight recent evidence suggesting that an accurate pain assessment may predict changes in the level of consciousness in unresponsive wakefulness syndrome/vegetative state patients, underscoring the importance of ongoing pain management in these patients.

Alleviation of Pain, PAIN Interference, and Oxidative Stress by a Novel Combination of Hemp Oil, Calamari Oil, and Broccoli: A Randomized, Double-Blind, Placebo-Controlled Trial

Chronic pain is a critical health issue in the US that is routinely managed pharmacologically with diminishing results. The widespread misuse and abuse of prescription opioid pain medications have caused both healthcare providers and patients to seek alternative therapeutic options. Several dietary ingredients have been traditionally used for pain relief and are known to have potential analgesic properties. This double-blind, placebo-controlled randomized clinical trial aimed to test whether a novel combination of full spectrum hemp oil (phytocannabinoids), calamari oil (omega-3 fatty acids), and broccoli (glucosinolates) could reduce chronic pain and attenuate damage from oxidative stress in adults seeking chiropractic care. Participants (average age = 54.8 ± 13.6 years old) were randomly assigned to consume a whole-food, multi-ingredient supplement (n = 12, intervention and standard chiropractic care) or placebo (n = 13, mineral oil and standard chiropractic care) daily for 12 weeks. The subjects' self-reported perceived pain, pain interference, and reactive oxygen species (ROS) status in the peripheral blood mononuclear cells (PBMC) were quantified at baseline, mid-checkpoint, and postintervention. The intervention was positively associated with a 52% decrease in pain intensity and several parameters of pain interference, including quality of sleep. Decreases in the markers of oxidative stress were also observed in the participants from the intervention group (29.4% decrease in PMBC ROS). Our findings indicated that supplementation with a novel combination of hemp oil, calamari oil, and broccoli has the potential to manage chronic pain when combined with standard chiropractic care, as suggested by its effects on pain intensity and oxidative stress.

Kynurenine Pathway Metabolites as Potential Biomarkers in Chronic Pain

Chronic pain is a pressing medical and socioeconomic issue worldwide. It is debilitating for individual patients and places a major burden on society in the forms of direct medical costs and lost work productivity. Various biochemical pathways have been explored to explain the pathophysiology of chronic pain in order to identify biomarkers that can potentially serve as both evaluators of and guides for therapeutic effectiveness. The kynurenine pathway has recently been a source of interest due to its suspected role in the development and sustainment of chronic pain conditions. The kynurenine pathway is the primary pathway responsible for the metabolization of tryptophan and generates nicotinamide adenine dinucleotide (NAD⁺), in addition to the metabolites kynurenine (KYN), kynurenic acid (KA), and quinolinic acid (QA). Dysregulation of this pathway and changes in the ratios of these metabolites have been associated with numerous neurotoxic and inflammatory states, many of which present simultaneously with chronic pain symptoms. While further studies utilizing biomarkers to elucidate the kynurenine pathway's role in chronic pain are needed, the metabolites and receptors involved in its processes nevertheless present researchers with promising sources of novel and personalized disease-modifying treatments.

Acute Pain Management in Traumatically Injured Patients With Outpatient Buprenorphine Therapy

INTRODUCTION

Acute pain management is challenging in trauma patients undergoing outpatient buprenorphine therapy at the time of injury due to the high binding affinity of this partial agonist. The purpose of this study was to evaluate acute pain management in admitted trauma patients with discontinued versus continued outpatient buprenorphine therapy.

MATERIALS AND METHODS

This retrospective study included adult trauma patients admitted to a level-1 trauma center between January 2017 and August 2020 who were receiving buprenorphine prior to admission. Groups were defined as buprenorphine discontinued (BD) or continued (BC) during hospitalization. The primary outcome compared median daily morphine milligram equivalents between groups. Secondary outcomes utilized patient-reported numeric rating scale (NRS) scores to compare incidences of no pain (NRS 0), mild (NRS 1-3), moderate (NRS 4-6), and severe (NRS 7-10) pain.

RESULTS

A total of 57 patients were included (BD 37 [64.9%] and BC 20 [35.1%]). The median (interquartile range) outpatient daily buprenorphine dose was similar between groups (8 [8-16] mg versus 16 [8-16], P = 0.25). Median daily morphine milligram equivalents was significantly higher during admission in the BD group (103.7 [80.7-166] versus 67 [30.8-97.4], P = 0.002). Incidence of no pain (7.1% versus 5.7%, P = 0.283), mild (5.5% versus 4.3%, P = 0.295), moderate (20.2%, 19.8%, P = 0.855), or severe (67.2% versus 70.2%, P = 0.185) pain was similar between BD and BC groups, respectively.

CONCLUSIONS

Continuation of outpatient buprenorphine therapy in acute trauma patients is associated with decreased daily opioid requirements and similar analgesic efficacy compared to patients with BD. Based on our findings, trauma patients receiving outpatient buprenorphine and not requiring ventilator support may benefit from buprenorphine continuation within 48 h of initial presentation.

Prevalence and correlates of prescription opioid use among US adults, 2019-2020

This study estimates the prevalence of prescription opioid use (POU) in the United States (US) in 2019-2020, both in the general population and specifically among adults with pain. It also identifies key geographic, demographic, and socioeconomic correlates of POU. Data were from the nationally-representative National Health Interview Survey 2019 and 2020 (N = 52,617). We estimated POU prevalence in the prior 12 months among all adults (18+), adults with chronic pain (CP), and adults with high-impact chronic pain (HICP). Modified Poisson regression models estimated POU patterns across covariates. We found POU prevalence of 11.9% (95% CI 11.5, 12.3) in the general population, 29.3% (95% CI 28.2, 30.4) among those with CP, and 41.2% (95% CI 39.2, 43.2) among those with HICP. Findings from fully-adjusted models include the following: In the general population, POU prevalence declined about 9% from 2019 to 2020 (PR = 0.91, 95% CI 0.85, 0.96). POU varied substantially across US geographic regions: It was significantly more common in the Midwest, West, and especially the South, where adults had 40% higher POU (PR = 1.40, 95% CI 1.26, 1.55) than in the Northeast. In contrast, there were no differences by rural/urban residence. In terms of individual characteristics, POU was lowest among immigrants and among the uninsured, and was highest among adults who were food insecure and/or not employed. These findings suggest that prescription opioid use remains high among American adults, especially those with pain. Geographic patterns suggest systemic differences in therapeutic regimes across regions but not rurality, while patterns across social characteristics highlight the complex, opposing effects of limited access to care and socioeconomic precarity. Against the backdrop of continuing debates about benefits and risks of opioid analgesics, this study identifies and invites further research about geographic regions and social groups with particularly high or low prescription opioid use.

Factors associated with frequent or daily use of prescription opioids among adults with chronic pain in the United States

OBJECTIVES

We aimed to estimate utilization rates of prescription opioids among adults with chronic pain in the United States (US) and identify factors associated with the frequent or daily use of prescription opioids.

METHODS

This was a case-control analysis of the 2019 National Health Interview Survey of adults.

RESULTS

Over 50.2 million adults in the US reported chronic pain in the past 3 months, but only 10.5% of this group said they used prescription opioids frequently or daily to manage their pain. Adults with chronic pain were significantly more likely to use opioids if they had incomes below the federal poverty level (15.7%), relied on public health insurance (14.8%), had been hospitalized in the past year (17.8%), or rated their health as fair or poor (18.4%). The highest rates of opioid use were reported among adults with severe (24.4%) or moderate disability (18.9%).

CONCLUSIONS

Approximately 5.3 million adults use prescription opioids frequently or daily to manage chronic pain. These individuals should receive regular clinical assistance to manage their pain, including medication management and, when appropriate, referral to evidence-based treatment programs for opioid use disorder.

Impact of COVID-19 pandemic on chronic pain and opioid use in marginalized populations: A scoping review

Introduction

The COVID-19 pandemic has had a variable effect on vulnerable populations, including patients with chronic pain who rely on opioid treatment or have comorbid opioid use disorder. Limited access to care due to isolation measures may lead to increased pain severity, worse mental health symptoms, and adverse opioid-related outcomes. This scoping review aimed to understand the impact of the COVID-19 pandemic on the dual epidemics of chronic pain and opioids in marginalized communities worldwide.

Methods

Searches of primary databases including PubMed, Web of Science, Scopus, and PsycINFO were performed in March 2022, restricting the publication date to December 1, 2019. The search yielded 685 articles. After title and abstract screening, 526 records were screened by title and abstract, 87 through full-text review, of which 25 articles were included in the final analysis.

Results

Our findings illuminate the differential distribution of pain burden across marginalized groups and how it serves to heighten existing disparities. Service disruptions due to social distancing orders and infrastructural limitations prevented patients from receiving the care they needed, resulting in adverse psychological and physical health outcomes. Efforts to adapt to COVID-19 circumstances included modifications to opioid prescribing regulations and workflows and expanded telemedicine services.

Conclusion

Results have implications for the prevention and management of chronic pain and opioid use disorder, such as challenges in adopting telemedicine in low-resource settings and opportunities to strengthen public health and social care systems with a multidisciplinary and multidimensional approach.

Current and emerging pharmacotherapies for opioid dependence treatments in adults: a comprehensive update

INTRODUCTION

Opioid use disorder (OUD) is characterized by compulsive opioid seeking and taking, intense drug craving, and intake of opioids despite negative consequences. The prevalence of OUDs has now reached an all-time high, in parallel with peak rates of fatal opioid-related overdoses, where 15 million individuals worldwide meet the criteria for OUD. Further, in 2020, 120,000 opioid-related deaths were reported worldwide with over 75,000 of those deaths occurring within the United States.

AREAS COVERED

In this review, we highlight pharmacotherapies utilized in patients with OUDs, including opioid replacement therapies, and opioid antagonists utilized for opioid overdoses and deterrent of opioid use. We also highlight newer treatments, such as those targeting the neuroimmune system, which are potential new directions for research given the recently established role of opioids in activating neuroinflammatory pathways, as well as over the counter remedies, including kratom, that may mitigate withdrawal.

EXPERT OPINION

To effectively treat OUDs, a deeper understanding of the current therapeutics being utilized, their additive effects, and the added involvement of the neuroimmune system are essential. Additionally, a complete understanding of opioid-induced neuronal alterations and therapeutics that target these abnormalities - including the neuroimmune system - is required to develop effective treatments for OUDs.

Endogenous opioid systems alterations in pain and opioid use disorder

Decades of research advances have established a central role for endogenous opioid systems in regulating reward processing, mood, motivation, learning and memory, gastrointestinal function, and pain relief. Endogenous opioid systems are present ubiquitously throughout the central and peripheral nervous system. They are composed of four families, namely the μ (MOPR), κ (KOPR), δ (DOPR), and nociceptin/orphanin FQ (NOPR) opioid receptors systems. These receptors signal through the action of their endogenous opioid peptides β-endorphins, dynorphins, enkephalins, and nociceptins, respectfully, to maintain homeostasis under normal physiological states. Due to their prominent role in pain regulation, exogenous opioids-primarily targeting the MOPR, have been historically used in medicine as analgesics, but their ability to produce euphoric effects also present high risks for abuse. The ability of pain and opioid use to perturb endogenous opioid system function, particularly within the central nervous system, may increase the likelihood of developing opioid use disorder (OUD). Today, the opioid crisis represents a major social, economic, and public health concern. In this review, we summarize the current state of the literature on the function, expression, pharmacology, and regulation of endogenous opioid systems in pain. Additionally, we discuss the adaptations in the endogenous opioid systems upon use of exogenous opioids which contribute to the development of OUD. Finally, we describe the intricate relationship between pain, endogenous opioid systems, and the proclivity for opioid misuse, as well as potential advances in generating safer and more efficient pain therapies.

Shared Genetic Regulatory Networks Contribute to Neuropathic and Inflammatory Pain: Multi-Omics Systems Analysis

The mechanisms of chronic pain are complex, and genetic factors play an essential role in the development of chronic pain. Neuropathic pain (NP) and inflammatory pain (IP) are two primary components of chronic pain. Previous studies have uncovered some common biological processes in NP and IP. However, the shared genetic mechanisms remained poorly studied. We utilized multi-omics systematic analyses to investigate the shared genetic mechanisms of NP and IP. First, by integrating several genome-wide association studies (GWASs) with multi-omics data, we revealed the significant overlap of the gene co-expression modules in NP and IP. Further, we uncovered the shared biological pathways, including the previously reported mitochondrial electron transport and ATP metabolism, and stressed the role of genetic factors in chronic pain with neurodegenerative diseases. Second, we identified 24 conservative key drivers (KDs) contributing to NP and IP, containing two well-established pain genes, IL1B and OPRM1, and some novel potential pain genes, such as C5AR1 and SERPINE1. The subnetwork of those KDs highlighted the processes involving the immune system. Finally, gene expression analysis of the KDs in mouse models underlined two of the KDs, SLC6A15 and KCNQ5, with unidirectional regulatory functions in NP and IP. Our study provides strong evidence to support the current understanding of the shared genetic regulatory networks underlying NP and IP and potentially benefit the future common therapeutic avenues for chronic pain.

Machine learning and deep learning frameworks for the automated analysis of pain and opioid withdrawal behaviors

The automation of behavioral tracking and analysis in preclinical research can serve to advance the rate of research outcomes, increase experimental scalability, and challenge the scientific reproducibility crisis. Recent advances in the efficiency, accuracy, and accessibility of deep learning (DL) and machine learning (ML) frameworks are enabling this automation. As the ongoing opioid epidemic continues to worsen alongside increasing rates of chronic pain, there are ever-growing needs to understand opioid use disorders (OUDs) and identify non-opioid therapeutic options for pain. In this review, we examine how these related needs can be advanced by the development and validation of DL and ML resources for automated pain and withdrawal behavioral tracking. We aim to emphasize the utility of these tools for automated behavioral analysis, and we argue that currently developed models should be deployed to address novel questions in the fields of pain and OUD research.

Overdose, opioid treatment admissions and prescription opioid pain reliever relationships: United States, 2010-2019

Background

"As part of the U.S. government's urgent response to the epidemic of overdose deaths (1)" the United States Centers for Disease Control and Prevention (CDC) issued the "CDC Guideline for Prescribing Opioids for Chronic Pain-United States, 2016 (2)" (guideline) followed by the "CDC Clinical Practice Guideline for Prescribing Opioids-United States, 2022 (3) (guideline update). " The guideline and guideline update cite a direct correlation between prescription opioids sales (POS) and opioid treatment admissions (OTA) and prescription opioid deaths (POD), which was based on data from 1999 to 2010. This paper updates those relationships and includes the correlations between prescription opioid sales (POS) and any opioid deaths (AOD) and total overdose deaths (TOD) from 2010 to 2019.

Methods

Linear regression models were fit to each response separately. Opioid sales (measured as MME (morphine milligram equivalent) per capita) was the independent variable. Total overdose deaths (TOD), any opioid overdose deaths (AOD), prescription opioid overdose deaths (POD) and opioid treatment admissions (OTA) were the dependent, response variables. The models were assessed using three criteria: the statistical significance of the model (Overall P-Value), the quality of the fit (R ²), and the sign of the slope coefficient (positive or negative).

Results

The analyses revealed that the direct correlations (i.e., significant, positive slopes) reported by the CDC based on data from 1999 to 2010 no longer exist. Based on data from 2010 to 2019, the relationships either have reversed (i.e., significant, negative slopes) or are non-existent (i.e., no significant model).

Conclusions

The guideline, guideline update, CDC's public, medical profession, and intergovernmental communications should be corrected/updated to state no direct correlation has existed between POS to OTA, POD, AOD, and TOD since 2010. Individualized patient care and public health policy should be amended accordingly.

Management of chronic non-cancer pain: a framework

Aim: Since publication of the CDC 2016 Guideline, opioid-related mortality in the USA has doubled and a crisis has developed among the 15-20 million Americans with chronic, moderate-to-severe, noncancer pain. Our aim was to develop a comprehensive alternative approach to management of chronic pain. Methods: Analytic review of the clinical literature. Results: Published science provides a solid framework for the management of chronic non-cancer pain, detailed here, even as it leaves many knowledge gaps, which we fill with insights from clinical experience. Conclusion: There is a sufficient basis in science and in clinical experience to achieve adequate control of chronic pain in nearly all patients in a way that adequately balances benefits and potential harms.

Virtual Reality Assisted Non-Pharmacological Treatments in Chronic Pain Management: A Systematic Review and Quantitative Meta-Analysis

Virtual reality (VR) is a developing technology that has recently attracted the attention of healthcare practitioners. Recently, VR systems have been used to treat pain symptoms. The present study aims to evaluate the VR effectiveness on chronic pain management. A systematic literature search was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Keywords were used to discover the potentially eligible studies. The primary focus of the present investigation was to evaluate the possible effect of VR-assisted treatments on chronic pain, especially in the commonly occurring low back and neck pain. Nine studies reporting randomized controlled trials were included in the present study. VR-mediated interventions demonstrated significant improvement for pain symptoms in patients experiencing chronic pain. In addition, VR-mediated therapy decreased pain intensity and disability in the case of chronic neck pain compared to control conditions. However, the VR interventions showed a statistically non-significant improvement in chronic low back pain when experimental groups were compared with controls. VR therapy positive effect on chronic pain did not differ from the one reported for other types of interventions for pain management, as physical exercise and laser therapy. Taken together, these findings showed that currently available lines of evidence on the effect of VR-mediated therapy in chronic pain management, despite pointing towards possible therapeutical benefits of the VR-based intervention, are overall inconclusive and that more research on VR-assisted therapy for chronic pain is needed.

Physician Liability for Suicide after Negligent Tapering of Opioids

The precipitous and medically contraindicated reduction or "tapering" of opioids for patients with chronic pain due to serious medical conditions has caused needless suffering and, increasingly, suicide. Physicians could be liable for wrongful death based on negligent tapering of opioids.

Utilizing Primary Care to Engage Patients on Opioids in a Psychological Intervention for Chronic Pain

INTRODUCTION

Given the risks of opioids for pain management, we need nonpharmacological interventions that patients will engage in and that can reduce opioid use. The purpose was to examine whether offering a psychological intervention in primary care can engage patients receiving opioids for pain management and to explore whether the intervention influences opioid use.

METHODS

This was a secondary analysis of a pilot randomized controlled trial (RCT) of a 5-session psychological intervention in primary care for chronic pain. Patients with chronic pain (N = 220) were approached to enroll in the RCT. Electronic health records were reviewed to determine whether patients were prescribed opioids or pain medications at the time they were approached about the RCT and the 6-months following the intervention.

RESULTS

Enrollees and non-enrollees had similar rates of opioid prescriptions, morphine milligram equivalent dose of opioids, and rates of other pain medication prescriptions (p> .05). However, no males with an opioid prescription enrolled. Though not significant, those in the intervention had lower odds of having an opioid prescription 6 months following the intervention (p= .09, OR= .32). Those randomized to the intervention had lower odds of having a non-opioid pain medication prescription (p= .01, OR= .17).

CONCLUSIONS

Having an opioid prescription did not interfere with enrollment, suggesting that primary care may be useful for engaging patients on opioids in a psychological treatment for chronic pain. However, this may be true for women, and not men. This intervention also showed promise for decreasing opioid use and warrants further study.