The Public Health Approach to the Worsening Opioid Crisis in the United States Calls for Harm Reduction Strategies to Mitigate the Harm From Opioid Addiction and Overdose Deaths

Developing predictive models for µ opioid receptor binding using machine learning and deep learning techniques

Opioids exert their analgesic effect by binding to the µ opioid receptor (MOR), which initiates a downstream signaling pathway, eventually inhibiting pain transmission in the spinal cord. However, current opioids are addictive, often leading to overdose contributing to the opioid crisis in the United States. Therefore, understanding the structure-activity relationship between MOR and its ligands is essential for predicting MOR binding of chemicals, which could assist in the development of non-addictive or less-addictive opioid analgesics. This study aimed to develop machine learning and deep learning models for predicting MOR binding activity of chemicals. Chemicals with MOR binding activity data were first curated from public databases and the literature. Molecular descriptors of the curated chemicals were calculated using software Mold2. The chemicals were then split into training and external validation datasets. Random forest, k-nearest neighbors, support vector machine, multi-layer perceptron, and long short-term memory models were developed and evaluated using 5-fold cross-validations and external validations, resulting in Matthews correlation coefficients of 0.528-0.654 and 0.408, respectively. Furthermore, prediction confidence and applicability domain analyses highlighted their importance to the models' applicability. Our results suggest that the developed models could be useful for identifying MOR binders, potentially aiding in the development of non-addictive or less-addictive drugs targeting MOR.

Sur la route des surdoses: un portrait canadien

OBJECTIVES

The overdose crisis continues to grow in Canada, and those involved in intervention must innovate to propose solutions. This exploratory research aims to paint a portrait of the situation, understand prevention efforts, and hear the experiences of people who have lived an overdose and those who intervene in this context.

METHODS

A qualitative, descriptive-interpretive approach was adopted. Data collection took place in 2021 and 2022 in four Canadian provinces and 11 cities. A variety of data collection methods were used, including a logbook, periods of participant observation, and semi-structured interviews with 39 caregivers, 10 peer caregivers, and 11 service users. A thematic analysis of the material was carried out.

RESULTS

Mobilizing Nancy Fraser's critical theory, our results present an inequitable distribution of resources, the exclusion of representation mechanisms, and institutionalized denials of recognition. Several interventions implemented in response to overdoses or transformed to better address the crisis are identified. We situate them according to the recognition and redistribution of solutions, whether more corrective or more radical.

CONCLUSION

Structural reforms aimed at improving the recognition and redistribution of resources are essential if interventions are to retain their innovative potential in the context of the overdose crisis, while being part of a longer-term aim of social transformation.

The resurgence of synthetic cannabinoid receptor agonists as adulterants in the Era of Cannabis legalization: Lessons from prior epidemics and clinical implications

Momentum towards legalization of medical and recreational cannabis drives a convergence between natural cannabinoids and their synthetic counterparts, creating new clinical challenges in a second wave of exposures. This review critically examines the emerging challenges posed by synthetic cannabinoid receptor agonists (SCRAs) and semi-synthetic cannabinoids, emphasizing their clinical implications. SCRAs are potent full agonist activity that have been identified as adulterants in several recreational substances, including cannabis and opioids. Adulteration often leads to unpredictable clinical outcomes and exacerbates the potential for drug interactions. Drawing parallels with other drug epidemics, this paper highlights the urgent need for clinical preparedness to address the nuanced presentations of cannabinoid toxicity, stressing the importance of patient history, physical examination, and judicious use of supportive laboratory tests. This review serves as a cautionary tale and call to action for researchers and policymakers. There is a clear need for robust quality control measures, enhanced public awareness campaigns, and development of evidence-based clinical guidelines to mitigate the health risks associated with intentional and unintentional use of synthetic cannabinoids.

A systematic review of macro-, meso, and micro-level harm reduction interventions addressing the U.S. opioid overdose epidemic

Background

This systematic review aimed to 1) identify the range of opioid harm reduction interventions implemented at macro-, meso-, and micro-levels in the United States, and 2) summarize the outcomes of these interventions.

Methods

We conducted a systematic review of academic literature published between 2011-2023 following PRISMA guidelines. Articles were excluded if they reported on research that was not specific to opioids, did not report the effects of an intervention, or focused on a medical treatment for opioid use disorder. Two coders independently extracted data and reconciled discrepancies prior to narrative synthesis.

Results

Of 6,198 articles initially identified, 36 met inclusion criteria across macro (n=7), meso (n=8), and micro (n=21) domains. Positive evidence for micro- and meso-level interventions is largely consistent, whereas evidence for macro-level interventions is mixed. Among micro- and meso-level interventions, supply distribution interventions were most effective in increasing safe use knowledge and behaviors among people who use drugs.

Discussion

Most harm reduction interventions demonstrate moderate to strong evidence of effectiveness for addressing the opioid overdose epidemic across domains. Findings revealed a lack of multi-level interventions and a lack of culturally relevant interventions that prioritize Black and Brown communities disproportionately impacted during the opioid overdose epidemic's latter phases.

Network Analysis of Medical Claims Data Suggests Network-Based, Regional Targeting and Intervention Delivery Strategies to Increase Access to Office Based Opioid Treatment (OBOT) for Opioid Use Disorder (OUD)

Opioid overdose and Opioid Use Disorder (OUD) statistics underscore an urgent need to significantly expand access to evidence-based OUD treatment. Office Based Opioid Treatment (OBOT) has proven effective for treating OUD. However, limited access to these treatments persists. Recognizing the need for significant investment in clinical, behavioral, and translational research, the Indiana State Department of Health and Indiana University embarked on a research initiative supported by the "Responding to the Addictions Crisis" Grand Challenge Program. This brief presents recommendations based on existing research and our own analyses of medical claims data in Indiana, where opioid misuse is high and treatment access is limited. The recommendations cover target providers, intervention focus, priority regions, and delivery methods.

Medication overdose data analysis: a review of medication error reports in the FDA adverse event reporting system (FAERS)

BACKGROUND

drug overdose is a common type of medication error, which caused significant patient injuries and economic losses. To determine which drugs are reported most frequently in association with drug overdose, a comprehensive search was conducted in the FDA Adverse Event Reporting System (FAERS) database. The study also sought to determine the top 10 drugs reported with drug overdose.

METHODS

FAERS database was searched for drug overdose records submitted from the first quarter of 2017 to the fourth quarter of 2021. Descriptive analyses were conducted based on the total counts and percentages of reports associated with the drug. Subgroup analyses were performed on drugs of different pharmacological classifications.

RESULTS

A total of 170,424 drug overdose reports were retrieved. The results revealed that antipyretics and analgesics took the highest risk for overdose, with 63,143 (37.05%) cases reported. Among them, opioids were associated with the most drug overdose events. The top 10 drug classes relating to drug overdose in FAERS were opioid analgesic, anilide antipyretic analgesic, 5-HT reuptake inhibitors, bronchodilators, monoclonal antibodies and antibody-drug conjugates, benzodiazepines, antipsychotics, GABA derivatives, antimanic agents, and propionic acid derivatives.

CONCLUSION

to reduce the occurrence of drug overdose events, some methods could be considered including applying a pre-prescription review system, drug safety education, developing warning lists, etc.

What is a public health approach to substance use? A qualitative systematic review and thematic synthesis

BACKGROUND

Psychoactive substance use and the regulations that govern it both have the potential to lead to harm. A 'public health approach' (PHA) is frequently invoked as a means of addressing these harms, but the term is used in inconsistent and contradictory ways. This study systematically reviewed the English-language academic literature to understand how a public health approach to substance use is defined and described.

METHODS

This review employed thematic synthesis, a methodology designed to rigorously synthesize qualitative evidence. Eligible articles were published in peer-reviewed journals, in the English language, with full text available, and focused primarily on substance use. There were no limits on year of publication. Original research, opinion/commentary, and reviews were included. The searches were conducted in October 2021 in CINAHL, Embase, Medline, PAIS Index, PsycINFO, Scopus, Sociological Abstracts, and Web of Science.

RESULTS

272 articles from 25 countries, published between 1950 and 2021, were synthesized. Definitions of a PHA have changed over time and differ by substance. The most commonly cited characteristics of a PHA were: for alcohol, regulation, e.g. of price and availability (54% of articles); for cannabis: regulation (68%); for illicit drugs: that a PHA is distinct from a criminal justice approach (63%); for opioids: substance use disorder treatment (55%); and for tobacco: regulation (62%).

CONCLUSION

There is no consensus on the definition of a public health approach to substance use, but there is substantial agreement when it comes to PHAs to specific substances. There are also similarities in how they are described for legal substances versus illicit ones. This review found areas of disagreement regarding the extent to which PHAs should focus on individual-level factors. Policymakers, academics, and others developing or implementing PHAs to substance use should be explicit about their aims and objectives - as well as the premises and assumptions underlying them.

The antidepressant agomelatine attenuates morphine-induced reinstatement but not self-administration or precipitated withdrawal

BACKGROUND

Exogenous melatonin appears to have anti-addictive properties and was recently shown to improve mental health and metabolic measures in patients receiving chronic opioid maintenance therapy. Agomelatine is a marketed antidepressant which acts as a melatonin agonist. We evaluated its effects using a rat model of morphine-reinforced behavior.

METHODS

After pretreatment with noncontingent morphine, male Wistar rats were trained to self-administer intravenous morphine (1.0 mg/kg-injection) under a progressive-ratio schedule. Rats were pretreated with vehicle or agomelatine during extinction, reinstatement, and reacquisition of morphine-reinforced behavior.

RESULTS

Daily treatment with 10 mg/kg-day of agomelatine decreased the number of ratios completed and prolonged latency during morphine-induced reinstatement. There were no significant effects on cue-induced reinstatement, morphine self-administration, or naloxone-precipitated withdrawal. Treatment with 32 mg/kg-day of agomelatine caused postural changes. That dose prolonged withdrawal-induced loss of body weight and caused delayed reductions in food reinforcement.

SUMMARY

In addition to postural effects, high-dose agomelatine worsened the course of spontaneous withdrawal and produced nonspecific effects on food-reinforced behavior. When administered at a selective dose, agomelatine did not modify morphine self-administration or precipitated withdrawal, but decreased morphine-induced reinstatement. Our findings show potential detrimental effects of high-dose agomelatine, with reductions in opioid-seeking behavior after a lower, more selective dose.

A National Study of Homelessness, Social Determinants of Health, and Treatment Engagement Among Outpatient Medication for Opioid Use Disorder-Seeking Individuals in the United States

BACKGROUND

Homelessness is an important social determinant of health (SDOH), impacting health outcomes for many medical conditions. Although homelessness is common among people with opioid use disorder (OUD), few studies systematically evaluate homelessness and other SDOH among people enrolled in standard of care treatment for OUD, medication for opioid use disorder (MOUD), or examine whether homelessness affects treatment engagement.

METHODS

Using data from the 2016 to 2018 U.S. Treatment Episode Dataset Discharges (TEDS-D), patient demographic, social, and clinical characteristics were compared between episodes of outpatient MOUD where homelessness was reported at treatment enrollment versus independent housing using pairwise tests adjusted for multiple testing. A logistic regression model examined the relationship between homelessness and treatment length and treatment completion while accounting for covariates.

RESULTS

There were 188 238 eligible treatment episodes. Homelessness was reported in 17 158 episodes (8.7%). In pairwise analysis, episodes involving homelessness were significantly different from those involving independent living on most demographic, social, and clinical characteristics, with significantly greater social vulnerability in most SDOH variables (P's < .05). Homelessness was significantly and negatively associated with treatment completion (coefficient = -0.0853, P < 0.001, 95% CI = [-0.114, -0.056], OR = 0.918) and remaining in treatment for greater than 180 days (coefficient = -0.3435, P < 0.001, 95% CI = [-0.371, -0.316], OR = 0.709) after accounting for covariates.

CONCLUSIONS

Patients reporting homelessness at treatment entry in outpatient MOUD in the U.S. represent a clinically distinct and socially vulnerable population from those not reporting homelessness. Homelessness independently predicts poorer engagement in MOUD confirming that homelessness may be an independent predictor for MOUD treatment discontinuation nationally.

Fentanyl Induces Novel Conditioned Place Preference in Adult Zebrafish, Disrupts Neurotransmitter Homeostasis, and Triggers Behavioral Changes

Abuse of new psychoactive substances increases risk of addiction, which can lead to serious brain disorders. Fentanyl is a synthetic opioid commonly used in clinical practice, and behavioral changes resulting from fentanyl addiction have rarely been studied with zebrafish models. In this study, we evaluated the rewarding effects of intraperitoneal injections of fentanyl at concentrations of 10, 100, and 1000 mg/L on the group shoaling behavior in adult zebrafish. Additional behavioral tests on individual zebrafish, including novel tank, novel object exploration, mirror attack, social preference, and T-maze memory, were utilized to evaluate fentanyl-induced neuro-behavioral toxicity. The high doses of 1000 mg/L fentanyl produced significant reward effects in zebrafish and altered the neuro-behavioral profiles: reduced cohesion in shoaling behavior, decreased anxiety levels, reduced exploratory behavior, increased aggression behavior, affected social preference, and suppressed memory in an appetitive associative learning task. Behavioral changes in zebrafish were shown to be associated with altered neurotransmitters, such as elevated glutamine (Gln), gamma-aminobutyric acid (GABA), dopamine hydrochloride (DA), and 5-hydroxytryptamine (5-HT). This study identified potential fentanyl-induced neurotoxicity through multiple neurobehavioral assessments, which provided a method for assessing risk of addiction to new psychoactive substances.