The life and times of endogenous opioid peptides: Updated understanding of synthesis, spatiotemporal dynamics, and the clinical impact in alcohol use disorder

The opioid G-protein coupled receptors (GPCRs) strongly modulate many of the central nervous system structures that contribute to neurological and psychiatric disorders including pain, major depressive disorder, and substance use disorders. To better treat these and related diseases, it is essential to understand the signaling of their endogenous ligands. In this review, we focus on what is known and unknown about the regulation of the over two dozen endogenous peptides with high affinity for one or more of the opioid receptors. We briefly describe which peptides are produced, with a particular focus on the recently proposed possible synthesis pathways for the endomorphins. Next, we describe examples of endogenous opioid peptide expression organization in several neural circuits and how they appear to be released from specific neural compartments that vary across brain regions. We discuss current knowledge regarding the strength of neural activity required to drive endogenous opioid peptide release, clues about how far peptides diffuse from release sites, and their extracellular lifetime after release. Finally, as a translational example, we discuss the mechanisms of action of naltrexone (NTX), which is used clinically to treat alcohol use disorder. NTX is a synthetic morphine analog that non-specifically antagonizes the action of most endogenous opioid peptides developed in the 1960s and FDA approved in the 1980s. We review recent studies clarifying the precise endogenous activity that NTX prevents. Together, the works described here highlight the challenges and opportunities the complex opioid system presents as a therapeutic target.

Estimating the impact of stimulant use on initiation of buprenorphine and extended-release naltrexone in two clinical trials and real-world populations

BACKGROUND

Co-use of stimulants and opioids is rapidly increasing. Randomized clinical trials (RCTs) have established the efficacy of medications for opioid use disorder (MOUD), but stimulant use may decrease the likelihood of initiating MOUD treatment. Furthermore, trial participants may not represent "real-world" populations who would benefit from treatment.

METHODS

We conducted a two-stage analysis. First, associations between stimulant use (time-varying urine drug screens for cocaine, methamphetamine, or amphetamines) and initiation of buprenorphine or extended-release naltrexone (XR-NTX) were estimated across two RCTs (CTN-0051 X:BOT and CTN-0067 CHOICES) using adjusted Cox regression models. Second, results were generalized to three target populations who would benefit from MOUD: Housed adults identifying the need for OUD treatment, as characterized by the National Survey on Drug Use and Health (NSDUH); adults entering OUD treatment, as characterized by Treatment Episodes Dataset (TEDS); and adults living in rural regions of the U.S. with high rates of injection drug use, as characterized by the Rural Opioids Initiative (ROI). Generalizability analyses adjusted for differences in demographic characteristics, substance use, housing status, and depression between RCT and target populations using inverse probability of selection weighting.

RESULTS

Analyses included 673 clinical trial participants, 139 NSDUH respondents (weighted to represent 661,650 people), 71,751 TEDS treatment episodes, and 1,933 ROI participants. The majority were aged 30-49 years, male, and non-Hispanic White. In RCTs, stimulant use reduced the likelihood of MOUD initiation by 32% (adjusted HR [aHR] = 0.68, 95% CI 0.49-0.94, p = 0.019). Stimulant use associations were slightly attenuated and non-significant among housed adults needing treatment (25% reduction, aHR = 0.75, 0.48-1.18, p = 0.215) and adults entering OUD treatment (28% reduction, aHR = 0.72, 0.51-1.01, p = 0.061). The association was more pronounced, but still non-significant among rural people injecting drugs (39% reduction, aHR = 0.61, 0.35-1.06, p = 0.081). Stimulant use had a larger negative impact on XR-NTX initiation compared to buprenorphine, especially in the rural population (76% reduction, aHR = 0.24, 0.08-0.69, p = 0.008).

CONCLUSIONS

Stimulant use is a barrier to buprenorphine or XR-NTX initiation in clinical trials and real-world populations that would benefit from OUD treatment. Interventions to address stimulant use among patients with OUD are urgently needed, especially among rural people injecting drugs, who already suffer from limited access to MOUD.

Emergency Department-Initiated Buprenorphine Treatment in a Population with a High Rate of Homelessness: An Observational Study

BACKGROUND

Buprenorphine is an effective treatment for opioid use disorders. A previous randomized trial comparing emergency department (ED)-initiated buprenorphine to standard care showed dramatic improvement in follow-up. This is encouraging, but must be replicated to understand the generalizability of buprenorphine treatment.

OBJECTIVES

Evaluate the efficacy of an ED-initiated buprenorphine protocol similar to a previous randomized trial in a different population.

METHODS

This ED-based descriptive study described the results of a project implementing an opioid use disorder treatment protocol that included buprenorphine. Patients with opioid use disorder were offered treatment with buprenorphine, a buprenorphine prescription whenever possible, and a follow-up visit to a clinic providing addiction treatment. The primary outcome was engagement in formal addiction treatment 30 days after the index visit.

RESULTS

Of the 210 patients who accepted referral for outpatient medication-assisted treatment, 95 (45.2%) achieved the primary outcome. Two-thirds of these patients received a buprenorphine prescription at discharge; 40% were homeless. A regression analysis revealed one statistically significant predictor of the primary outcome: patients who were housed were 2.49 times more likely to engage in opioid use disorder treatment than patients who were homeless (p = 0.02).

CONCLUSIONS

In this descriptive study of an ED-initiated buprenorphine protocol, follow-up was less than that reported in a previous randomized controlled trial. Two important differences between our study and the randomized trial are the high rate of homelessness and the fact that not every patient received a prescription for buprenorphine. The efficacy of ED-initiated treatment may depend on certain population characteristics.

"Helping the Helpers"-Making Access to Buprenorphine the New Standard of Care for Physicians in State Monitoring Programs

This commentary argues that the Federation of State Medical Board's (FSMB) recommendations concerning the use of buprenorphine for physicians in their state-affiliated monitoring programs falls short of effectively permitting an evidence-based treatment for opioid use disorder. Although the FSMB acknowledges the benefits of medications for opioid use disorder and recommends that physicians who elect to start on buprenorphine receive treatment safely and privately, the FSMB is opposed to health care professionals practicing while on buprenorphine. Their rationale is based on the notion that physicians are exceptional in their ability to remain in recovery without medications for opioid use disorder and the unsupported assumption that buprenorphine causes significant cognitive impairment. This commentary contends that FSMB policy recommendations should work to destigmatize and indeed support evidence-based treatments for physicians with substance use disorders.

Pilot implementation of the PharmNet naloxone program in an independent pharmacy

BACKGROUND

The U.S. overdose epidemic has continued to escalate with more than 100,000 deaths per year in the past several years, most of which involve opioids. Widespread availability of naloxone is part of a national solution to the crisis, and community pharmacies are well-poised to facilitate such distribution and provide additional harm reduction services.

OBJECTIVES

The primary objectives of this study were to (a) examine the usability of each of the separate intervention components prepared for PharmNet, (b) observe intervention fidelity through regularly scheduled site visits, and (c) explore the association between PharmNet implementation and the volume of naloxone sales and distribution in the pilot site.

PRACTICE DESCRIPTION

Here, we describe a carefully designed and tailored pharmacy harm reduction intervention called PharmNet that is designed to maximize harm reduction impact while minimizing utilization of pharmacist resources. It is a pragmatic awareness, service provision, and referral program that was developed through careful, iterative feasibility studies with pharmacists.

PRACTICE INNOVATION

PharmNet procedures include tools and steps to create awareness (e.g., yard signs and messaging for patients, reminder tools for pharmacists), facilitation of naloxone delivery from nonprofits, and provision of referral cards featuring local resources.

EVALUATION METHODS

Evaluation included direct data collection and randomly scheduled fidelity site visits.

RESULTS

The intervention was associated with an increase of 3.33 naloxone doses/mo being dispensed at cost (34.4% relative increase) and an overall increase of 9.33 naloxone doses/mo being dispensed via any mechanism (96.48% relative increase). Around 2.85 referral cards were issued to patients daily. Intervention fidelity was moderate, and the study provides valuable information for how to modify the study prior to a randomized trial.

CONCLUSION

With modifications informed by this pilot study, the PharmNet intervention merits a randomized trial to determine whether it causes increased naloxone dispensing in independent community pharmacies.

Support, don't punish: Drug decriminalization is harm reduction

Despite large investments in and policy support for harm reduction including naloxone, syringes, and medications for opioid use disorder, people who use drugs continue to experience unprecedented rates of mortality from overdose and morbidity from infectious diseases. The criminalization of drug use has disproportionately exacerbated these drug-related harms and imposed short- and long-term burdens on already marginalized and vulnerable populations. Pharmacy professionals and students are not immune to the effects of drug criminalization, where one conviction can lead to the loss of their license, employment, or educational progress. Communities become less healthy and stagnate in punitive criminalization systems, further reducing opportunities for growth. Decriminalization of drug use and possession is an urgently needed and effective approach to drug use that shifts resources from punishment to public health, thereby reducing the negative impacts of drug use and keeping communities safe and healthy. Pharmacists play essential roles in the prevention and management of drug misuse and use disorders. As policy makers consider and implement drug decriminalization, pharmacists must actively advocate for these policies and educate community and organizational partners on the individual, professional, and community benefits of this harm reduction strategy.

Patient Satisfaction With Standard Methadone and Flexible Buprenorphine/Naloxone Models of Care: Results From a Pragmatic Randomized Controlled Clinical Trial

INTRODUCTION

Patient satisfaction is a critical measure of quality of care across health disciplines because it may affect clinical outcomes.

OBJECTIVES

This study aimed to examine longitudinal patient satisfaction in individuals with opioid use disorder (OUD) randomized to receive either standard methadone or flexible buprenorphine/naloxone models of care, its predictors, and association with dropout/illicit drug use.

METHODS

This study assessed patient satisfaction, using the 8-item version of the Client Satisfaction Questionnaire (CSQ), as a secondary outcome of a large phase IV pragmatic randomized controlled trial (OPTIMA). The effectiveness of standard methadone model of care was compared with flexible take-home buprenorphine/naloxone dispensation model of care in patients with prescription-type OUD. Of 272 participants recruited and followed up for 24 weeks, 183 were eligible for this study.

RESULTS

Throughout the study, patients were "satisfied" with their treatment. The average CSQ score was not significantly different between weeks 4, 12, and 24 in the total sample (χ 2 = 0.35; P = 0.84). There was no significant difference in CSQ based on treatment assignment (methadone vs flexible buprenorphine/naloxone) either overall ( z = 0.87; P = 0.38) or over time (χ 2 = 0.65; P = 0.72). High levels of depression at baseline and decreased depressive symptoms over the follow-up period predicted positive changes in patient satisfaction ( P = 0.03 and P = <0.01, respectively). Satisfaction was significantly associated with treatment retention but not illicit drug use.

CONCLUSIONS

This study demonstrates that patients with OUD on either standard methadone or flexible buprenorphine were generally satisfied with their treatment, with no difference in patient satisfaction based on treatment allocation. Given the ongoing opioid crisis, strategies to improve patient satisfaction should be further explored.

Expanding the accessibility of harm reduction services in the United States: Measuring the impact of an automated harm reduction dispensing machine

BACKGROUND

In 2021, approximately 107,622 Americans died from drug overdose in the United States. With overdose deaths rising rapidly, it is imperative that prevention efforts focus on expanding proven, evidence-based strategies to curb overdose death rates such as targeted naloxone distribution and syringe service programs (SSPs). The COVID-19 pandemic placed additional strain on SSPs, increasing the need for programs that minimize direct contact and potential COVID-19 exposure. The purpose of this study is to evaluate the impact of an automated harm reduction dispensing machine on the local accessibility of harm reduction services.

OBJECTIVES

The primary outcome of the study is the number of harm reduction supplies distributed to the community by the dispensing machine in its first year compared to the number of supplies distributed by the same organization in the previous year. Secondary outcomes include the countywide incidence of fatal drug overdose and human immunodeficiency virus (HIV) compared to previous years.

METHODS

The machine is located outside, in the same location as a once weekly, in-person SSP. Clients register with the program over the phone with a harm reduction coordinator. Each client is connected to products and services such as naloxone, sharps containers, safer injection/smoking kits, pregnancy tests, HIV tests, substance use disorder treatment, and more.

RESULTS

Since installation, 637 individuals registered with the program, 12% of whom had never reportedly used harm reduction services before. Within its first year of use, the machine dispensed 3360 naloxone doses and 10,155 fentanyl test strips, more than any other SSP in the county.

CONCLUSION

The implementation of an automated harm reduction dispensing machine led to an increased accessibility of harm reduction products and services and was associated with a lower countywide incidence of unintentional overdose death and HIV. The association with decreased overdose death and HIV incidence should be further investigated to assess causality.

"I've been to more of my friends' funerals than I've been to my friends' weddings": Witnessing and responding to overdose in rural Northern New England

PURPOSE

Overdose is a leading cause of death among people who use drugs (PWUDs), but policies to reduce fatal overdose have had mixed results. Summaries of naloxone access and Good Samaritan Laws (GSLs) in prior studies provide limited information about local context. Witnessing overdoses may also be an important consideration in providing services to PWUDs, as it contributes to post traumatic stress disorder (PTSD) symptoms, which complicate substance use disorder treatment.

METHODS

We aim to estimate the prevalence and correlates of witnessing and responding to an overdose, while exploring overdose context among rural PWUD. The Drug Injection Surveillance and Care Enhancement for Rural Northern New England (DISCERNNE) mixed-methods study characterized substance use and risk behaviors in 11 rural Massachusetts, Vermont, and New Hampshire counties between 2018 and 2019. PWUD completed surveys (n = 589) and in-depth interviews (n = 22).

FINDINGS

Among the survey participants, 84% had ever witnessed an overdose, which was associated with probable PTSD symptoms. Overall, 51% had ever called 911 for an overdose, though some experienced criminal legal system consequences despite GSL. Although naloxone access varied, 43% had ever used naloxone to reverse an overdose.

CONCLUSIONS

PWUD in Northern New England commonly witnessed an overdose, which they experienced as traumatic. Participants were willing to respond to overdoses, but faced barriers to effective overdose response, including limited naloxone access and criminal legal system consequences. Equipping PWUDs with effective overdose response tools (education and naloxone) and enacting policies that further protect PWUDs from criminal legal system consequences could reduce overdose mortality.

NMDA Receptors in the Rat Paraventricular Thalamic Nucleus Reduce the Naloxone-induced Morphine Withdrawal

BACKGROUND

NMDA receptors have a significant role in the development of opioid physical dependence. Evidence demonstrated that a drug of abuse enhances neuronal excitability in the Paraventricular Nucleus (PVT). The current research studied whether blocking NMDA receptors through the administration of MK801 in the PVT nucleus could affect the development of Morphine (Mor) dependence and hence the behavioral indices induced by morphine withdrawal in rats.

METHODS

Male Wistar rats weighing 250-300 g were used. For induction of drug dependence, we injected Mor subcutaneously (s.c.) (6, 16, 26, 36, 46, 56, and 66 mg/kg, 2 ml/kg) at an interval of 24 hours for 7 days. Animals were divided into two groups in which the NMDA receptor antagonist, MK801 (20 mM in 0.1 ml), or its vehicle were applied into the PVT nucleus for 7 days before each Mor administration. On day 8, after injection of naloxone (Nal, 2.5 mg/kg, i.p.), withdrawal behaviors were checked for 25 min.

RESULTS

The current results demonstrated that the blockade of the NMDA receptor in the PVT nucleus significantly increased withdrawal behaviors provoked by the application of Nal in morphinedependent (Mor-d) rats.

CONCLUSION

We concluded that the NMDA receptor in the PVT nucleus changes the development of Mor dependence.

Lowering barriers to naloxone access through a student-led harm reduction program

BACKGROUND

In recent years, the opioid crisis has had devastating effects on communities across the country. In the wake of 4 University of Southern California (USC) student overdose deaths in 2019, USC pharmacy students initiated a naloxone distribution program called NaloxoneSC. This program has distributed free naloxone kits, fentanyl test strips, and overdose prevention training to hundreds of students thus far. This report aims to provide a framework for the implementation of similar harm reduction programs at other universities.

OBJECTIVES

NaloxoneSC partnered with USC Student Health to implement a naloxone distribution program that expands access to naloxone and increases opioid overdose education within the USC community.

SETTING

USC undergraduate campus and Health Sciences Campus.

METHODS

Students can follow the steps for obtaining a naloxone kit listed on the NaloxoneSC website. Watching a 10-minute training video or attending a naloxone training workshop completes the opioid overdose education. The kit is picked up by the student from 1 of 2 USC Student Health Center locations, Engemann or Eric Cohen. Each kit is packaged with Narcan nasal spray and fentanyl test strips.

RESULTS

In 1 year, the program received at least 320 naloxone kit requests. Demand for naloxone kits increased over time, and roughly 4 times as many students requested kits from Engemann than from Eric Cohen. Approximately 600 students have received opioid overdose education through NaloxoneSC.

CONCLUSIONS

In 1 year, more than 300 USC students voluntarily requested naloxone kits from NaloxoneSC. These findings suggest a need for increased access to this resource on college campuses. Peer-to-peer education and naloxone kit distribution are feasible and effective strategies that help address public health concerns and reduce harm among university students. NaloxoneSC can serve as an example for other college campuses or entities to newly implement or expand their own harm reduction measures.

Association Between Sublingual Buprenorphine-Naloxone Exposure and Dental Disease

This study examines the association of sublingual buprenorphine/naloxone and dental adverse events using the IQVIA health claims database.

Naloxone Prescribing Associated With Reduced Emergency Department Visits in the Military Health System

PURPOSE

The aim was to determine the association between the receipt of naloxone and emergency department (ED) visits within 60 days after the receipt of an opioid.

METHODS

A retrospective cohort of individuals 18 years of age or above, enrolled in TRICARE, and were dispensed an opioid at any time from January 1, 2019, through September 30, 2020 was identified within the United States Military Health System. Individuals receiving naloxone within 5 days of the opioid dispensing date were propensity score matched with individuals receiving opioids only. A logistic regression was used to estimate the odds of an ED visit in the 60-day follow-up period after the index opioid dispense event among those co-dispensed naloxone and those receiving opioids only.

RESULTS

Of the 2,136,717 individuals who received an opioid prescription during the study period, 800,071 (10.1%) met study inclusion criteria. Overall, 5096 (0.24%) of individuals who received an opioid prescription were co-dispensed naloxone. Following propensity score matching, those who received naloxone had a significantly lower odds of ED utilization in the 60 days after receiving an opioid prescription (odds ratio: 0.74, 95% CI: 0.68-0.80, P<0.001).

CONCLUSION

This study highlights the importance of expanding access to naloxone in order to reduce ED utilization. Future research is needed to examine additional outcomes related to naloxone receipt and develop programs that make naloxone prescribing a routine practice.

Polysubstance use before and during treatment with medication for opioid use disorder: Prevalence and association with treatment outcomes

OBJECTIVE

Polysubstance use may complicate treatment outcomes for individuals who use opioids. This research aimed to examine the prevalence of polysubstance use in an opioid use disorder treatment trial population and polysubstance use's association with opioid relapse and craving.

METHODS

This study is a secondary data analysis of individuals with opioid use disorder who received at least one dose of medication (n = 474) as part of a 24-week, multi-site, open label, randomized Clinical Trials Network study (CTN0051, X:BOT) comparing the effectiveness of extended-release naltrexone versus buprenorphine. Models examined pretreatment polysubstance use and polysubstance use during the initial 4 weeks of treatment on outcomes of relapse by week 24 of the treatment trial and opioid craving.

RESULTS

Polysubstance use was generally not associated with treatment outcomes of opioid relapse and craving. Proportion of days of pretreatment sedative use was associated with increased likelihood of opioid relapse (OR: 1.01, 95 % CI: 1.00-1.02). Proportion of days of cocaine use during the initial 4 weeks of treatment was associated with increased likelihood of opioid relapse (OR: 1.05, 95 % CI: 1.01-1.09) but this effect was no longer significant once the potential of confounding by opioid use was considered. Sedative use during initial 4 weeks of treatment was associated with increased opioid craving (b: 0.77, 95 % CI: 0.01-1.52). The study found no other significant relationships.

CONCLUSIONS

In the current study population, polysubstance use was only marginally associated with 24-week treatment outcomes.

Use of long-acting injectable buprenorphine in the correctional setting

BACKGROUND

As overdoses due to opioids rise, medications for opioid use disorder (MOUD) continue to be underemployed, resulting in limited access to potentially life-saving treatment. Substance use disorders are prevalent in individuals who are incarcerated, and these individuals are at increased risk for death postrelease due to overdose. Few jails and prisons offer MOUD and most limit access. Extended-release buprenorphine (XR-BUP), a novel monthly injectable MOUD formulation, could be uniquely poised to address treatment access in correctional settings.

METHODS

This study linked a retrospective cohort design of statewide datasets to evaluate the real-world use of XR-BUP. The study included individuals (N = 54) who received XR-BUP while incarcerated from January 2019 through February 2022. The study was conducted at the Rhode Island Department of Corrections, with the nation's first comprehensive statewide correctional MOUD program.

RESULTS

Fifty-four individuals received a combined total of 162 injections during the study period. The study found no evidence of tampering with the injection site, indicating no attempts by participants to remove, hoard, or divert the medication. Sixty-one percent reported at least one adverse effect after injections were received, with an average of 2.8 side effects. Sixty-one percent of those released on XR-BUP engaged in MOUD after release, 30 % continued with XR-BUP.

CONCLUSIONS

XR-BUP is feasible and acceptable in correctional settings. XR-BUP addresses administrative concerns of diversion that obstruct lifesaving MOUD and offers another safe and effective treatment option. Further studies and trials should continue to assess this novel medication's ability to treat opioid addiction in the correctional setting and upon release to the community.

Models for Implementing Emergency Department-Initiated Buprenorphine With Referral for Ongoing Medication Treatment at Emergency Department Discharge in Diverse Academic Centers

There has been a substantial rise in the number of publications and training opportunities on the care and treatment of emergency department (ED) patients with opioid use disorder over the past several years. The American College of Emergency Physicians recently published recommendations for providing buprenorphine to patients with opioid use disorder, but barriers to implementing this clinical practice remain. We describe the models for implementing ED-initiated buprenorphine at 4 diverse urban, academic medical centers across the country as part of a federally funded effort termed "Project ED Health." These 4 sites successfully implemented unique ED-initiated buprenorphine programs as part of a comparison of implementation facilitation to traditional educational dissemination on the uptake of ED-initiated buprenorphine. Each site describes the elements central to the ED process, including screening, treatment initiation, referral, and follow-up, while harnessing organizational characteristics, including ED culture. Finally, we discuss common facilitators to program success, including information technology and electronic medical record integration, hospital-level support, strong connections with outpatient partners, and quality improvement processes.

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.

Supraspinal melatonin MT2 receptor agonism alleviates pain via a neural circuit that recruits mu opioid receptors

Melatonin, through its G protein-coupled receptor (GPCR) (MTNR1B gene) MT₂ , is implicated in analgesia, but the relationship between MT₂ receptors and the opioid system remains elusive. In a model of rodent neuropathic pain (spared nerve injured [SNI]), the selective melatonin MT₂ agonist UCM924 reversed the allodynia (a pain response to a non-noxious stimulus), and this effect was nullified by the pharmacological blockade or genetic inactivation of the mu opioid receptor (MOR), but not the delta opioid receptor (DOR). Indeed, SNI MOR, but not DOR knockout mice, did not respond to the antiallodynic effects of the UCM924. Similarly, the nonselective opioid antagonist naloxone and the selective MOR antagonist D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP) blocked the effects of UCM924 in SNI rats, but not the DOR antagonist naltrindole (NTI). Electrophysiological recordings in the rostral-ventromedial medulla (RVM) revealed that the typical reduction of the firing activity of pronociceptive ON-cells, and the enhancement of the firing of the antinociceptive OFF-cells, induced by the microinjection of the MT₂ agonist UCM924 into the ventrolateral periaqueductal gray (vlPAG) were blocked by MOR, but not DOR, antagonism. Immunohistochemistry studies showed that MT₂ receptors are expressed in both excitatory (CaMKIIα⁺ ) and inhibitory (GAD65⁺ ) neuronal cell bodies in the vlPAG (~2.16% total), but not RVM. Only 0.20% of vlPAG neurons coexpressed MOR and MT₂ receptors. Finally, UCM924 treatment induced an increase in the enkephalin precursor gene (PENK) in the PAG of SNI mice. Collectively, the melatonin MT₂ receptor agonism requires MORs to exert its antiallodynic effects, mostly through an interneuronal circuit involving MOR and MT₂ receptors.

Maintenance on extended-release naltrexone is associated with reduced injection opioid use among justice-involved persons with opioid use disorder

INTRODUCTION

Opioid use disorder (OUD) and injection drug use (IDU) place justice-involved individuals at increased risk for acquiring or transmitting HIV or hepatitis C virus (HCV). Methadone and buprenorphine have been associated with reduced opioid IDU; however, the effect of extended-release naltrexone (XR-NTX) on this behavior is incompletely studied.

METHODS

This study examined injection opioid use and shared injection equipment behavior from a completed double-blind placebo-controlled trial of XR-NTX among 88 justice-involved participants with HIV and OUD. Changes in participants' self-reported daily injection opioid use and shared injection equipment was evaluated pre-incarceration, during incarceration, and monthly post-release for 6 months. The study also assessed differences in time to first opioid injection post-release. The research team performed intention to treat and "as treated" (high treatment versus low treatment) analyses.

RESULTS

Fifty-eight of 88 participants (69.5 %) endorsed IDU and 26 (29.5 %) reported sharing injection equipment in the 30 days pre-incarceration; 2 participants (2.2 %) reported IDU during incarceration; 19 (21.6 %) reported IDU one month post-release from prison or jail. Fifty-four (61.4 %) participants had an HIV RNA below 200 copies/mL and 62 (70.5 %) were baseline HCV antibody positive. The 6-month follow-up rate was 49.5 % and 50.5 % for those who received XR-NTX and placebo, respectively, which was not significantly different (p = 0.822). Participants in the XR-NTX and placebo groups had similar low mean opioid injection use post-release and time to first injection opioid use in the Intention-to-treat analysis. In the as-treated analysis, participants in the high treatment group had significantly lower mean proportion of days injecting opioids (13.8 % high treatment versus 22.8 % low treatment, p = 0.02) by month 1, which persisted up to 5 months post-release (0 % high treatment vs 24.3 % low treatment, p < 0.001) and experienced a longer time to first opioid injection post-release (143.8 days high treatment vs 67.4 days low treatment, p < 0.001).

CONCLUSIONS

Injection opioid use was low during incarceration and remained low post-release in this justice-involved population. Retention on XR-NTX was associated with reduced intravenous opioid use, which has important implications for reducing transmission of HIV and HCV.

Identification of Non-Fatal Opioid Overdose Cases Using 9-1-1 Computer Assisted Dispatch and Prehospital Patient Clinical Record Variables

Background: The current epidemic of opioid overdoses in the United States necessitates a robust public health and clinical response. We described patterns of non-fatal opioid overdoses (NFOODs) in a small western region using data from the 9-1-1 Computer Assisted Dispatch (CAD) record and electronic Patient Clinical Records (ePCR) completed by EMS responders. We determined whether CAD and ePCR variables could identify NFOOD cases in 9-1-1 data for intervention and surveillance efforts. Methods: We conducted a retrospective analysis of 1 year of 9-1-1 emergency medical CAD and ePCR (including naloxone administration) data from the sole EMS provider in the response area. Cases were identified based on clinician review of the ePCR, and categorized as definitive NFOOD, probable NFOOD, or non-OOD. Sensitivity, specificity, positive and negative predictive values (PPV and NPV) of the most prevalent CAD and ePCR variables were calculated. We used a machine learning technique-Random-Forests (RF) modeling-to optimize our ability to accurately predict NFOOD cases within census blocks. Results: Of 37,960 9-1-1 calls, clinical review identified 158 NFOOD cases (0.4%), of which 123 (77.8%) were definitive and 35 (22.2%) were probable cases. Overall, 106 (67.1%) received naloxone from the EMS responder at the scene. As a predictor of NFOOD, naloxone administration by paramedics had 67.1% sensitivity, 99.6% specificity, 44% PPV, and 99.9% NPV. Using CAD variables alone achieved a sensitivity of 36.7% and specificity of 99.7%. Combining ePCR variables with CAD variables increased the diagnostic accuracy with the best RF model yielding 75.9% sensitivity, 99.9% specificity, 71.4% PPV, and 99.9% NPV. Conclusion: CAD problem type variables and naloxone administration, used alone or in combination, had sub-optimal predictive accuracy. However, a Random Forests modeling approach improved accuracy of identification, which could foster improved surveillance and intervention efforts. We identified the set of NFOODs that EMS encountered in a year and may be useful for future surveillance efforts.

Experience and response to a randomised controlled trial of extended-release injectable buprenorphine versus sublingual tablet buprenorphine and oral liquid methadone for opioid use disorder: protocol for a mixed-methods evaluation

INTRODUCTION

Opioid use disorder (OUD) is a debilitating and persistent disorder. The standard-of-care treatment is daily maintenance dosing of sublingual buprenorphine (BUP-SL) or oral methadone (MET). Monthly, extended-release, subcutaneous injectable buprenorphine (BUP-XR) has been developed to enhance treatment effectiveness. This study aims to investigate the experiences of participants who have been offered BUP-XR (evaluation 1), health-related quality-of-life among participants who have opted to receive BUP-XR longer term (evaluation 2) and the experiences of participants allocated to receive BUP-XR or BUP-SL or MET with the offer of adjunctive personalised psychosocial intervention (evaluation 3).

METHODS AND ANALYSIS

Three qualitative-quantitative (mixed-methods) evaluations embedded in a five-centre, head-to-head, randomised controlled trial of BUP-XR versus BUP-SL and MET in the UK. Evaluation 1 is a four-centre interview anchored on an OUD-related topic guide and conducted after the 24-week trial endpoint. Evaluation 2 is a two-centre interview anchored on medications for opioid use disorder-specific quality-of-life topic guide conducted among participants after 12-24 months. Evaluation 3: single-centre interview after the 24-week trial endpoint. All evaluations include selected trial clinical measures, with evaluation 2 incorporating additional questionnaires. Target participant recruitment for evaluations 1 and 2 is 15 participants per centre (n=60 and n=30, respectively). Recruitment for evaluation 3 is 15 participants per treatment arm (n=30). Each evaluation will be underpinned by theory, drawing on constructs from the behavioural model for health service use or the health-related quality-of-life model. Qualitative data analysis will be by iterative categorisation.

ETHICS AND DISSEMINATION

Study protocol, consent materials and questionnaires were approved by the London-Brighton and Sussex research ethics committee (reference: 19/LO/0483) and the Health Research Authority (IRAS project number 255522). Participants will be provided with information sheets and informed written consent will be obtained for each evaluation. Study findings will be disseminated through peer-reviewed scientific journals.

TRIAL REGISTRATION NUMBER

2018-004460-63.

Effectiveness of two extended-release buprenorphine formulations during postoperative period in neonatal rats

Information on the effectiveness of a new long-lasting buprenorphine formulation, extended-release buprenorphine, in the neonatal rat is very limited. This study compares whether a high dose of extended-release buprenorphine (XR-Hi) attenuates thermal hypersensitivity for a longer period than a low dose of extended-release buprenorphine (XR-Lo) in a neonatal rat incisional pain model. Two experiments were performed. Experiment one: Male and female postnatal day-5 rat pups (n = 38) were randomly assigned to 1 of 4 treatment groups and received a subcutaneous administration of one of the following: 1) 0.9%NaCl (Saline), 0.1 mL; 2) sustained release buprenorphine (Bup-SR), 1 mg/kg; 3) XR-Lo, 0.65 mg/kg; and 4) XR-Hi, 1.3 mg/kg. Pups were anesthetized with sevoflurane in 100% O₂ and a 5 mm long skin incision was made over the left lateral thigh and underlying muscle dissected. The skin was closed with surgical tissue glue. Thermal hypersensitivity testing (using a laser diode) and clinical observations were conducted 1 hour (h) prior to surgery and subsequently after 1, 4, 8, 24, 48, 72 h of treatment. Experiment two: The plasma buprenorphine concentration level was evaluated at 1, 4, 8, 24, 48, 72 h on five-day-old rat pups. Plasma buprenorphine concentration for all treatment groups remained above the clinically effective concentration of 1 ng/mL for at least 4 h in the Bup-SR group, 8 h in XR-Lo and 24 h in XR-Hi group with no abnormal clinical observations. This study demonstrates that XR-Hi did not attenuate postoperative thermal hypersensitivity for a longer period than XR-Lo in 5-day-old rats; XR-Hi attenuated postoperative thermal hypersensitivity for up to 4 h while Bup-SR and XR-Lo for at least 8 h in this model.

Oxycodone-Naloxone Combination Hinders Opioid Consumption in Osteoarthritic Chronic Low Back Pain: A Retrospective Study with Two Years of Follow-Up

Chronic low back pain (CLBP) due to osteoarthritis represents a therapeutic challenge worldwide. Opioids are extensively used to treat such pain, but the development of tolerance, i.e., less susceptibility to the effects of the opioid, which can result in a need for higher doses to achieve the same analgesic effect, may limit their use. Animal models suggest that ultra-low doses of opioid antagonists combined with opioid agonists can decrease or block the development of opioid tolerance. In this retrospective study, we tested this hypothesis in humans. In 2019, 53 patients suffering from CLBP were treated with either Oxycodone and Naloxone Prolonged Release (27 patients, OXN patients) or Oxycodone Controlled Release (26 patients, OXY patients). The follow-up period lasted 2 years, during which 10 patients discontinued the treatment, 5 out of each group. The remaining 43 patients reached and maintained the targeted pain relief, but at 18 and 24 months, the OXY patients showed a significantly higher oxycodone consumption than OXN patients to reach the same level of pain relief. No cases of respiratory depression or opioid abuse were reported. There were no significant differences in the incidence of adverse effects between the two treatments, except for constipation, more common in OXY patients. From our results, we can affirm that a long-term opioid treatment with oxycodone-naloxone combination, when compared with oxycodone only, may significantly hinder the development of opioid tolerance. We were also able to confirm, in our cohort, the well known positive effect of naloxone in terms of opioid-induced bowel dysfunction incidence reduction.

A measurement invariance analysis of selected Opioid Overdose Knowledge Scale (OOKS) items among bystanders and first responders

The Opioid Overdose Knowledge Scale (OOKS) is widely used as an adjunct to opioid education and naloxone distribution (OEND) for assessing pre- and post-training knowledge. However, the extent to which the OOKS performs comparably for bystander and first responder groups has not been well determined. We used exploratory structural equation modeling (ESEM) to assess the measurement invariance of an OOKS item subset when used as an OEND training pre-test. We used secondary analysis of pre-test data collected from 446 first responders and 1,349 bystanders (N = 1,795) attending OEND trainings conducted by two county public health departments. Twenty-four items were selected by practitioner/trainer consensus from the original 45-item OOKS instrument with an additional 2 removed owing to low response variation. We used exploratory factor analysis (EFA) followed by ESEM to identify a factor structure, which we assessed for configural, metric, and scalar measurement invariance by participant group using the 22 dichotomous items (correct/incorrect) as factor indicators. EFA identified a 3-factor model consisting of items assessing: basic overdose risk information, signs of an overdose, and rescue procedures/advanced overdose risk information. Model fit by ESEM estimation versus confirmatory factor analysis showed the ESEM model afforded a better fit. Measurement invariance analyses indicated the 3-factor model fit the data across all levels of invariance per standard fit statistic metrics. The reduced set of 22 OOKS items appears to offer comparable measurement of pre-training knowledge on opioid overdose risks, signs of an overdose, and rescue procedures for both bystanders and first responders.

Analysis of US County Characteristics and Clinicians With Waivers to Prescribe Buprenorphine After Changes in Federal Education Requirements

This cross-sectional study investigates the growth in the number of clinicians in the US who obtained waivers for prescribing buprenorphine after the elimination of federal educational requirements.

Buprenorphine & methadone dosing strategies to reduce risk of relapse in the treatment of opioid use disorder

BACKGROUND

Although there is consensus that having a "high-enough" dose of buprenorphine (BUP-NX) or methadone is important for reducing relapse to opioid use, there is debate about what this dose is and how it should be attained. We estimated the extent to which different dosing strategies would affect risk of relapse over 12 weeks of treatment, separately for BUP-NX and methadone.

METHODS

This was a secondary analysis of three comparative effectiveness trials. We examined four dosing strategies: 1) increasing dose in response to participant-specific opioid use, 2) increasing dose weekly until some minimum dose (16 mg BUP, 100 mg methadone) was reached, 3) increasing dose weekly until some minimum and increasing dose in response to opioid use thereafter (referred to as the "hybrid strategy"), and 4) keeping dose constant after the first 2 weeks of treatment. We used a longitudinal sequentially doubly robust estimator to estimate contrasts between dosing strategies on risk of relapse.

RESULTS

For BUP-NX, increasing dose following the hybrid strategy resulted in the lowest risk of relapse. For methadone, holding dose constant resulted in greatest risk of relapse; the other three strategies performed similarly. For example, the hybrid strategy reduced week 12 relapse risk by 13 % (RR: 0.87, 95 %CI: 0.83-0.95) and by 20 % (RR: 0.80, 95 %CI: 0.71-0.90) for BUP-NX and methadone respectively, as compared to holding dose constant.

CONCLUSIONS

Doses should be targeted toward minimum thresholds and, in the case of BUP-NX, raised when patients continue to use opioids.

Addressing the opioid epidemic through community pharmacy engagement: Study protocol for a randomized controlled trial

BACKGROUND

Despite the authority to dispense naloxone, pharmacists have been reluctant to offer and dispense it, often due to discomfort communicating about the sensitive topic of opioid overdose. Because existing online naloxone trainings do not sufficiently address how to communicate effectively with patients about naloxone, Nalox-Comm, a training module designed to improve pharmacists' self-efficacy to engage in naloxone discussions, was developed.

OBJECTIVE

To describe the study protocol to evaluate the effectiveness of the Nalox-Comm training module on naloxone dispensing rates.

METHODS

A randomized controlled trial, which began in July 2021, is used to evaluate the pre-post Nalox-Comm training intervention. Sixty pharmacists are being recruited from 62 pharmacies part of a single grocery store chain in rural counties of the southeastern United States. After completing a baseline survey, pharmacists are observed by simulated patients (SPs) who rate the quality of their pre-training naloxone communication. Pharmacists are then invited to complete either a basic online naloxone training module (control group) or a newly developed Nalox-Comm training (experimental group), after which they complete a post-training survey and are observed a second time by SPs. Three months post-training, study participants complete a final follow-up survey. Naloxone dispensing records are obtained from each participating pharmacy to assess change in naloxone dispensing rates.

CONCLUSION

Informed by rural pharmacist stakeholders, the Nalox-Comm training module addresses communication barriers specific to rural communities. Compared to those in the control group, we hypothesize that pharmacies in the experimental group will dispense more naloxone in the three months post-training intervention.

Cost-effectiveness of extended-release injectable naltrexone among incarcerated persons with opioid use disorder before release from prison versus after release

INTRODUCTION

Opioid use disorder (OUD) is highly prevalent among incarcerated populations, and the risk of fatal overdose following release from prison is substantial. Despite efficacy, few correctional facilities provide evidence-based addiction treatment. Extended-release injectable naltrexone (XR-NTX) administered prior to release from incarceration may improve health and economic outcomes.

METHODS

We conducted an economic evaluation alongside a randomized controlled trial testing the effectiveness of XR-NTX before release from prison (n = 38) vs. XR-NTX referral after release (n = 48) of incarcerated participants with OUD, both groups continuing treatment at a community addiction treatment center. The incremental cost-effectiveness ratio (ICER) assessed the cost-effectiveness of XR-NTX before release compared to referral after release for three stakeholder perspectives at 12- and 24-week periods: state policymaker, health care sector, and societal. Effectiveness measures included quality-adjusted life-years (QALYs) and abstinent years from opioids. In addition, we categorized resources as OUD-related and non-OUD-related medical care, state transfer payments, and other societal costs (productivity, criminal justice resources, etc.).

RESULTS

Results showed an association between XR-NTX and greater OUD-related costs and total costs from the state policymaker perspective. QALYs gained were positive but statistically insignificant between arms; however, results showed XR-NTX had an estimated 15.5 more days of opioid abstinence over 24 weeks and statistically significant at a 95 % confidence level based on the distribution of bootstrapped samples. We found that estimated ICERs to be > $500,000 per QALY for all stakeholder perspectives. For the abstinent-year effectiveness measure, we found XR-NTX before release to be cost-effective at a 95 % confidence level for willingness-to-pay values >$49,000 per abstinent-year, across all perspectives.

CONCLUSIONS

XR-NTX administered to persons who are incarcerated with OUD before release may provide value for stakeholders and bridge a well-known treatment gap for this vulnerable population. Lower than expected participant engagement and missing data limit our results, and study outcomes may be sensitive to methods that address missing data if replicated.

Student pharmacists' attitudes, perceptions, and knowledge regarding opioid use, misuse, and overdose: Four years of data

INTRODUCTION

The American Association of Colleges of Pharmacy has urged pharmacy faculty to commit to actions to reduce the public health threat from opioid use and misuse. Optimizing student pharmacist training necessitates understanding changes in their attitudes and perceptions over time. This study assessed student attitudes, perceptions, and understanding of addiction, opioid use and misuse, and opioid overdose over four sequential years, from 2016 to 2019.

METHODS

The participants were third-professional year doctor of pharmacy students enrolled in a required course. Participants voluntarily completed a 27-statement survey to determine student attitudes, perceptions, and understanding.

RESULTS

A total of 452 participants completed the survey (response rate = 76.5%). Of the 27 survey items, five survey statements showed year on year positive increases in specific student attitudes towards addiction, hopefulness for its treatment, and confidence to use and train opioid overdose reversal agents. These yearly changes did not appear to be related to any changes in the academic aptitude of the students. The 22 remaining statements showed positive and stable attitudes towards self-perceived understanding of opioid use and misuse, hopefulness for its treatment, and the role of pharmacists.

CONCLUSION

To our knowledge, this is the first large multiyear assessment of student pharmacists' attitudes, perceptions, and understanding of opioid use, misuse, and overdose. The data indicate favorable and improving attitudes. Knowledge of student attitudes, perceptions, and understanding regarding opioid use, misuse, and overdose will aid in the development of effective training programs for students in our, and other colleges of pharmacy.

Pharmacological interventions for the treatment of disordered and problem gambling

BACKGROUND

Pharmacological interventions for disordered and problem gambling have been employed in clinical practice. Despite the availability of several reviews of the efficacy of pharmacological interventions for disordered or problem gambling, few have employed systematic search strategies or compared different categories of pharmacological interventions. Systematic reviews of high-quality evidence are therefore essential to provide guidance regarding the efficacy of different pharmacological interventions for disordered or problem gambling.

OBJECTIVES

The primary aims of the review were to: (1) examine the efficacy of major categories of pharmacological-only interventions (antidepressants, opioid antagonists, mood stabilisers, atypical antipsychotics) for disordered or problem gambling, relative to placebo control conditions; and (2) examine the efficacy of these major categories relative to each other.  SEARCH METHODS: We searched the Cochrane Common Mental Disorders Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), Ovid MEDLINE, Embase, and PsycINFO (all years to 11 January 2022).

SELECTION CRITERIA

We included randomised trials evaluating a pharmacological intervention for the treatment of disordered or problem gambling. Eligible control conditions included placebo control groups or comparisons with another category of pharmacological intervention.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures, including systematic extraction of included study characteristics and results and risk of bias assessment. Our primary outcome was reduction in gambling symptom severity. Our secondary outcomes were reduction in gambling expenditure, gambling frequency, time spent gambling, depressive symptoms, anxiety symptoms, and functional impairment; and responder status. We evaluated treatment effects for continuous and dichotomous outcomes using standardised mean difference (SMD) and risk ratios (RR), respectively, employing random-effects meta-analyses. A minimum of two independent treatment effects were required for a meta-analysis to be conducted (with only meta-analytic findings reported in this abstract).

MAIN RESULTS

We included 17 studies in the review (n = 1193 randomised) that reported outcome data scheduled for end of treatment. Length of treatment ranged from 7 to 96 weeks.  Antidepressants: Six studies (n = 268) evaluated antidepressants, with very low to low certainty evidence suggesting that antidepressants were no more effective than placebo at post-treatment: gambling symptom severity (SMD -0.32, 95% CI -0.74 to 0.09, n = 225), gambling expenditure (SMD -0.27, 95% CI -0.60 to 0.06, n = 144), depressive symptoms (SMD -0.19, 95% CI -0.60 to 0.23, n = 90), functional impairment (SMD -0.15, 95% CI -0.53 to 0.22, n = 110), and responder status (RR 1.24, 95% CI 0.93 to 1.66, n = 268). Opioid antagonists: Four studies (n = 562) evaluated opioid antagonists, with very low to low certainty evidence showing a medium beneficial effect of treatment on gambling symptom severity relative to placebo at post-treatment (SMD -0.46, 95% CI -0.74 to -0.19, n = 259), but no difference between groups in responder status (RR 1.65, 95% CI 0.86 to 3.14, n = 562). Mood stabilisers: Two studies (n = 71) evaluated mood stabilisers (including anticonvulsants), with very low certainty evidence suggesting that mood stabilisers were no more effective than placebo at post-treatment: gambling symptom severity (SMD -0.92, 95% CI -2.24 to 0.39, n = 71), depressive symptoms (SMD -0.15, 95% CI -1.14 to 0.83, n = 71), and anxiety symptoms (SMD -0.17, 95% CI -0.64 to 0.30, n = 71). Atypical antipsychotics:Two studies (n = 63) evaluated the atypical antipsychotic olanzapine, with very low certainty evidence showing a medium beneficial effect of treatment on gambling symptom severity relative to placebo at post-treatment (SMD -0.59, 95% CI -1.10 to -0.08, n = 63). Comparative effectiveness: Two studies (n = 62) compared antidepressants with opioid antagonists, with very low certainty evidence indicating that antidepressants were no more effective than opioid antagonists on depressive symptoms (SMD 0.22, 95% CI -0.29 to 0.72, n = 62) or anxiety symptoms (SMD 0.21, 95% CI -0.29 to 0.72, n = 62) at post-treatment. Two studies (n = 58) compared antidepressants with mood stabilisers (including anticonvulsants), with very low certainty evidence indicating that antidepressants were no more effective than mood stabilisers on depressive symptoms (SMD 0.02, 95% CI -0.53 to 0.56, n = 58) or anxiety symptoms (SMD 0.16, 95% CI -0.39 to 0.70, n = 58) at post-treatment. Tolerability and adverse events: Several common adverse effects were reported by participants receiving antidepressants (e.g. headaches, nausea, diarrhoea/gastrointestinal issues) and opioid antagonists (e.g. nausea, dry mouth, constipation). There was little consistency in the types of adverse effects experienced by participants receiving mood stabilisers (e.g. tiredness, headaches, concentration difficulties) or atypical antipsychotics (e.g. pneumonia, sedation, increased hypomania). Discontinuation of treatment due to these adverse events was highest for opioid antagonists (10% to 32%), followed by antidepressants (4% to 31%), atypical antipsychotics (14%), and mood stabilisers (13%).

AUTHORS' CONCLUSIONS

This review provides preliminary support for the use of opioid antagonists (naltrexone, nalmefene) and atypical antipsychotics (olanzapine) to produce short-term improvements in gambling symptom severity, although a lack of available evidence precludes a conclusion regarding the degree to which these pharmacological agents can improve other gambling or psychological functioning indices. In contrast, the findings are inconclusive with regard to the effects of mood stabilisers (including anticonvulsants) in the treatment of disordered or problem gambling, and there is limited evidence to support the efficacy of antidepressants. However, these conclusions are based on very low to low certainty evidence characterised by a small number of included studies, high risk of bias, modest pooled sample sizes, imprecise estimates, moderate between-study heterogeneity, and exclusion of participants with psychiatric comorbidities. Moreover, there were insufficient studies to conduct meta-analyses on many outcome measures; to compare efficacy across and within major categories of interventions; to explore dosage effects; or to examine effects beyond post-treatment. These limitations suggest that, despite recommendations related to the administration of opioid antagonists in the treatment of disordered or problem gambling, pharmacological interventions should be administered with caution and with careful consideration of patient needs. A larger and more methodologically rigorous evidence base with longer-term evaluation periods is required before definitive conclusions can be drawn about the effectiveness and durability of pharmacological treatments for disordered or problem gambling.

Impact of Impulsivity, Hyperactivity, and Inattention on Discontinuation Rate among Opioid-Dependent Patients Treated with Extended-Release Naltrexone

Previous studies have indicated elevated levels of impulsivity, hyperactivity, and inattention (IHI) among opioid-dependent patients seeking outpatient treatment with extended-release naltrexone (XR-NTX). This led us to hypothesize that IHI may be associated with a higher discontinuation rate for XR-NTX treatment. In a group of 162 patients with opioid dependence, discontinuation prior to the full 24 weeks of the study period (six injections and attending the study visit at 24 weeks) occurred in 49% of the patients, primarily in the early stage of treatment. IHI above the clinical cut-off on the adult ADHD self-report scale (ASRS) was not associated with a risk of premature discontinuation. This finding was not altered when controlling for socio-demographics, substance, use and mental health severity. Conclusively, high levels of IHI per se is not contradictive for XR-NTX treatment in regard to concern for premature discontinuation.

Evaluating the Impact of a Tribal Naloxone Program Through Pre and Post Surveys from First Responders

The Choctaw Nation Health Care Center established a first responder naloxone program in 2015. Limited data is available on community naloxone programs specific to tribal communities and the opinions of first responders who may utilize naloxone in the field. The purpose of this article is to highlight the model of a tribal first responder naloxone program in Talihina, Oklahoma and present analysis of the impact of program trainings on first responders' understanding and willingness to administer intranasal naloxone through pre- and post-surveys (n = 758) collected from May 2018 to November 2019. Descriptive analyses were conducted to compare first responders' rating of their support, willingness, and confidence in using naloxone. Overall, 95.1% of first responders reported learning something new from the training. However, the most significant changes in pre- to post-test results were among first responders that had never been at the scene of an overdose. Almost 77% of trainees who reported they never were at a scene of an overdose and responded "not very willing" in administering naloxone at pre-test, responded that they were "very willing" to administer naloxone at post-test.

When Effects Cannot be Estimated: Redefining Estimands to Understand the Effects of Naloxone Access Laws

Violations of the positivity assumption (also called the common support condition) challenge health policy research and can result in significant bias, large variance, and invalid inference. We define positivity in the single- and multiple-timepoint (i.e., longitudinal) health policy evaluation setting, and discuss real-world threats to positivity. We show empirical evidence of the practical positivity violations that can result when attempting to estimate the effects of health policies (in this case, Naloxone Access Laws). In such scenarios, an alternative is to estimate the effect of a shift in law enactment (e.g., the effect if enactment had been delayed by some number of years). Such an effect corresponds to what is called a modified treatment policy, and dramatically weakens the required positivity assumption, thereby offering a means to estimate policy effects even in scenarios with serious positivity problems. We apply the approach to define and estimate the longitudinal effects of Naloxone Access Laws on opioid overdose rates.

Identification of a novel opioid, N-piperidinyl etonitazene (etonitazepipne), in patients with suspected opioid overdose

BACKGROUND

Novel opioids in the illicit drug supply, such as the "nitazene" group of synthetic opioids, present an ongoing public health problem due to high potency and respiratory depressant effects. We describe three patients in whom N-piperidinyl etonitazene, a compound not previously reported in human exposure, was detected after suspected opioid overdose. Other substances that these patients tested for included fentanyl, cocaine, levamisole, phenacetin, benzoylecgonine, para-fluorofentanyl, presumptive heroin (tested as 6-monoacetylmorphine (6-MAM), morphine, and codeine), and tramadol.

METHODS

This is a case series of patients with acute opioid overdose enrolled in an ongoing multicenter prospective cohort study. Data collected included reported substance use, clinical course, naloxone dose and response, outcome, and analytes detected in biological samples.

RESULTS

Between October 6, 2020 and October 31, 2021, 1006 patients were screened and 412 met inclusion criteria. Of these, three patients (age 33-55) tested positive for N-piperidinyl etonitazene at one site in New Jersey over a period of three days in July 2021. Two patients reported the use of cocaine; one reported the use of heroin and alprazolam. All three patients received naloxone with improvement in their mental status (2 milligrams (mg) intranasally (IN); 8 mg IN; 0.08 mg intravenous (IV)). Two of three received subsequent doses for recurrence of opioid toxicity (0.4-0.6 mg IV). One patient was diagnosed with pneumonia and admitted to the intensive care unit, one was discharged from the Emergency Department (ED), and one used additional drug while in the ED and required admission for a naloxone infusion. None developed organ damage or sequelae.

CONCLUSION

These cases represent a local outbreak of a novel "nitazene" opioid. Public health toxicosurveillance should incorporate routine testing of this emerging class of synthetic compounds in the illicit drug supply.

Reasons for leaving treatment among patients with opioid dependence: A 3-month prospective follow-up study

OBJECTIVE

This study aimed to ascertain the reasons why patients with opioid dependence leave treatment.

DESIGN

Prospective follow-up observational study.

SETTING

This study was carried out at a tertiary care substance use treatment facility in north India with both outpatient and inpatient services. The facility is a public-funded institution.

PARTICIPANTS

One hundred and twenty opioid-dependent male patients with age 18 years or more who were willing to provide a valid telephone number for followup and willing to consent for the study were included.

MAIN OUTCOME MEASURE(S)

Enquiries were made using the Reasons to Leave Treatment Questionnaire (RLTQ) and an open-ended question about why the patient left treatment.

RESULTS

As per the RLTQ, the most common reasons for patients with opioid dependence leaving treatment were in the domains of external influence, motivational inconsistencies, and problem severity. Logistic problem was another issue that was highlighted by the patients. On open-ended question, the most common reason for leaving treatment pertained to feeling that one has improved and does not need treatment. Baseline characteristics that predicted patients leaving treatment were not being prescribed buprenorphine at discharge, not being formally educated, and living alone or in a nuclear family.

CONCLUSION

Several factors may lead to patients with opioid dependence leaving treatment prematurely after receiving inpatient care. Addressing these reasons might help to better retain patients in treatment and improve their outcomes.

Importance of Analyzing Intervals to Emergency Medical Service Treatments

BACKGROUND

Although most US emergency medical services (EMS) systems collect time-to-treatment data in their electronic prehospital patient care reports (PCRs), analysis of these data seldom appears in publications. We believe EMS agencies should routinely analyze the initial time-to-treatment data for various potentially life-threatening conditions. This not only assures that protocol-required treatments have been provided but can discover avoidable delays and drive protocol/treatment priority change. Our study purpose was to analyze the interval from 9-1-1 call receipt until the first administration of naloxone to adult opioid overdose victims to demonstrate the quality assurance importance of analyzing time-to-treatment data.

METHODS

Retrospective analysis of intervals from 9-1-1 call receipt to initial naloxone treatment in adult opioid overdose victims. We excluded victims <18 years of age and cases where a bystander, police, or a health care worker gave naloxone before EMS arrival. We compared data collected before and during the COVID-19 pandemic to determine its effect on the analysis.

RESULTS

The mean patient age of 582 opioid overdose victims was 40.7 years [95% CI 39.6, 41.8] with 405 males (69.6%). EMS units' scene arrival was 6.7 minutes from the 9-1-1 call receipt. It took 1.8 minutes to reach the victim, and 8.6 additional minutes to administer the first naloxone regardless of administration route (70.4% intravenous, 26.1% intranasal, 2.7% intraosseous, 0.7% intramuscular). EMS personnel administered the first naloxone 17.1 minutes after the 9-1-1 call receipt, with 50.3% of the delay occurring after patient contact. There was no statistically significant difference in the times-to-treatment before vs. during the pandemic.

CONCLUSION

The prepandemic interval from 9-1-1 call receipt until initial EMS administration of naloxone was substantial and did not change significantly during COVID-19. Our findings exemplify why EMS agencies should analyze initial time-to-treatment data, especially for life-threatening conditions, beyond assuring that protocol-required treatments have been provided. Based on our analysis, fire department crews now carry intranasal naloxone, and intranasal naloxone is given to "impaired" opioid overdose victims the first-arriving fire department or EMS personnel. We continue to collect data on intervals-to-treatment prospectively and monitor our critical process/treatment intervals using the plan-do-study-act model to improve our process/carry out change, and publish our results in a future publication.

Naloxone Co-Dispensing with Opioids: a Cluster Randomized Pragmatic Trial

BACKGROUND

Although naloxone prevents opioid overdose deaths, few patients prescribed opioids receive naloxone, limiting its effectiveness in real-world settings. Barriers to naloxone prescribing include concerns that naloxone could increase risk behavior and limited time to provide necessary patient education.

OBJECTIVE

To determine whether pharmacy-based naloxone co-dispensing affected opioid risk behavior. Secondary objectives were to assess if co-dispensing increased naloxone acquisition, increased patient knowledge about naloxone administration, and affected opioid dose and other substance use.

DESIGN

Cluster randomized pragmatic trial of naloxone co-dispensing.

SETTING

Safety-net health system in Denver, Colorado, between 2017 and 2020.

PARTICIPANTS

Seven pharmacies were randomized. Pharmacy patients (N=768) receiving opioids were followed using automated data for 10 months. Pharmacy patients were also invited to complete surveys at baseline, 4 months, and 8 months; 325 survey participants were enrolled from November 15, 2017, to January 8, 2019.

INTERVENTION

Intervention pharmacies implemented workflows to co-dispense naloxone while usual care pharmacies provided usual services.

MAIN MEASURES

Survey instruments assessed opioid risk behavior; hazardous drinking; tobacco, cannabis, and other drug use; and knowledge. Naloxone dispensings and opioid dose were evaluated using pharmacy data among pharmacy patients and survey participants. Intention-to-treat analyses were conducted using generalized linear mixed models accounting for clustering at the pharmacy level.

KEY RESULTS

Opioid risk behavior did not differ by trial group (P=0.52; 8-month vs. baseline adjusted risk ratio [ARR] 1.07; 95% CI 0.78, 1.47). Compared with usual care pharmacies, naloxone dispensings were higher in intervention pharmacies (ARR 3.38; 95% CI 2.21, 5.15) and participant knowledge increased (P=0.02; 8-month vs. baseline adjusted mean difference 1.05; 95% CI 0.06, 2.04). There was no difference in other substance use by the trial group.

CONCLUSION

Co-dispensing naloxone with opioids effectively increased naloxone receipt and knowledge but did not increase self-reported risk behavior.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov ; Identifier: NCT03337100.

Effects of Daily Methocinnamox Treatment on Fentanyl Self-Administration in Rhesus Monkeys

Methocinnamox (MCAM), a long-acting μ-opioid receptor antagonist, attenuates the positive reinforcing effects of opioids, such as heroin and fentanyl, suggesting it could be an effective treatment of opioid use disorder (OUD). Because treatment of OUD often involves repeated administration of a medication, this study evaluated effects of daily injections of a relatively small dose of MCAM on fentanyl self-administration and characterized the shift in the fentanyl dose-effect curve. Rhesus monkeys (3 males and 2 females) lever-pressed for intravenous infusions of fentanyl (0.032-10 μg/kg infusion) or cocaine (32-100 μg/kg infusion) under a fixed-ratio 30 schedule. MCAM (0.032 mg/kg) or naltrexone (0.0032-0.032 mg/kg) was administered subcutaneously 60 or 15 minutes, respectively, before sessions. When administered acutely, naltrexone and MCAM decreased fentanyl self-administration, with effects of naltrexone lasting less than 24 hours and effects of MCAM lasting for up to 3 days. Daily MCAM treatment attenuated responding for fentanyl, but not cocaine; effects were maintained for the duration of treatment with responding recovering quickly (within 2 days) following discontinuation of treatment. MCAM treatment shifted the fentanyl dose-effect curve in a parallel manner approximately 20-fold to the right. Naltrexone pretreatment decreased fentanyl intake with equal potency before and after MCAM treatment, confirming sensitivity of responding to antagonism by an opioid receptor antagonist. Although antagonist effects of treatment with a relatively small dose were surmountable, MCAM produced sustained and selective attenuation of opioid self-administration, supporting the view that it could be an effective treatment of OUD. SIGNIFICANCE STATEMENT: Opioid use disorder and opioid overdose continue to be significant public health challenges despite the availability of effective treatments. Methocinnamox (MCAM) is a long-acting μ-opioid receptor antagonist that blocks the reinforcing and ventilatory depressant effects of opioids in nonhuman subjects. This study demonstrates that daily treatment with MCAM reliably and selectively decreases fentanyl self-administration, further supporting the potential therapeutic utility of this novel antagonist.

Disparities in naloxone prescriptions in a University Hospital during the COVID-19 pandemic

BACKGROUND

Per the CDC, it is estimated that 69,710 opioid overdose deaths occurred in the United States from September 2019 to September 2020. However, it is unclear whether naloxone prescribing also increased or otherwise fluctuated in this time. The objective of this study was to characterize the naloxone prescribing rate in patients with opioid use disorder (OUD) at the University of Alabama at Birmingham Hospital in 2019 and 2020.

METHODS

A cross-sectional, retrospective medical record review was performed on patients with OUD from January 2019 through December 2020. Naloxone prescribing, defined as either a written prescription or a provided take-home kit, was assessed for all patients with OUD.

RESULTS

In 2019, 11,959 visits were made by 2962 unique patients with OUD, compared to 11,661 visits from 2,641 unique patients in 2020; 609 naloxone prescriptions were provided in 2019 (5.1%) and 619 in 2020 (5.3%). In both years, most OUD-related visits and naloxone prescriptions were from and to male, white, individuals. Compared with 2019, more naloxone prescriptions were given to uninsured patients in 2020 (33.2% vs 44.3%, p < 0.05), and more OUD patients were admitted to inpatient settings (26.0% vs 31.2%, p < 0.05) and received more naloxone prescriptions in the inpatient setting (46.3% vs 62.0%, p < 0.05) in 2020. The proportion of frequent users (i.e., visits ≥ 4 times/year) increased in 2020 for the emergency department (21.5% vs 26.4%, p < 0.001) and inpatient setting (24.9% vs 28.6%, p = 0.03).

CONCLUSIONS

Our findings indicate the need for improving naloxone awareness in providers and prescribing for patients with OUD, particularly in emergency department and outpatient settings. Our results also demonstrated a disparity in naloxone prescribing; a disproportionate number of opioid-related emergency department visits and overdose deaths were noted in Black people and frequent users.