Charting the fourth wave: Geographic, temporal, race/ethnicity and demographic trends in polysubstance fentanyl overdose deaths in the United States, 2010-2021

Racial/ethnic trends in opioid and polysubstance opioid overdose mortality in adolescents and young adults, 1999-2020

OBJECTIVES

Previous reports have described variations in opioid overdose mortalities among different race/ethnicity groups. We have analyzed racial/ethnicity trends in opioid and polysubstance opioid overdose mortalities in adolescents and young adults to further characterize differences and potential sub-epidemics within this specific population.

METHODS

We used mortality data from the U.S. Centers for Disease Control and Prevention Wide-Ranging Online Data for Epidemiologic Research (WONDER) Multiple Cause of Death file from 1999 to 2020. Drug overdose mortalities were identified using International Classification of Diseases, Tenth Revision (ICD-10) codes. Joinpoint regression was used to examine mortality rates for all opioids, opioids with a stimulant, opioids with benzodiazepines, and opioids with alcohol among racial/ethnic groups (non-Hispanic white, non-Hispanic Black, Hispanic, non-Hispanic other) in adolescents and young adults.

RESULTS

The Average Annual Percent Change (AAPC) for mortality due to opioid and polysubstance opioid overdose increased for all racial/ethnic groups where data was available for analysis from 1999 to 2020. For mortality due to any opioid and any opioid with a stimulant, the greatest AAPC was seen among non-Hispanic Blacks.

CONCLUSIONS

Unprecedented increases in mortality due to opioid overdose occurred in the last two decades among adolescents and young adults. Heterogenous trends support the notion that the previously defined opioid overdose epidemic "waves" may not accurately depict the effects of the crisis in all race/ethnicity groups. Additionally, alarming increases in opioid-stimulant overdose mortality starting in 2012 further characterize the interrelated effects of the third and fourth waves.

Transcranial magnetic stimulation for methamphetamine use disorder: A scoping review within the neurocircuitry model of addiction

The use of methamphetamine in the United States is increasing, contributing now to the "fourth wave" in the national opioid epidemic crisis. People who suffer from methamphetamine use disorder (MUD) have a higher risk of death. No pharmacological interventions are approved by the FDA and psychosocial interventions are only moderately effective. Transcranial Magnetic Stimulation (TMS) is a relatively novel FDA-cleared intervention for the treatment of Major Depressive Disorder (MDD) and other neuropsychiatric conditions. Several lines of research suggest that TMS could be useful for the treatment of addictive disorders, including MUD. We will review those published clinical trials that show potential effects on craving reduction of TMS when applied over the dorsolateral prefrontal cortex (DLPFC) also highlighting some limitations that affect their generalizability and applicability. We propose the use of the Koob and Volkow's neurocircuitry model of addiction as a frame to explain the brain effects of TMS in patients with MUD. We will finally discuss new venues that could lead to a more individualized and effective treatment of this complex disorder including the use of neuroimaging, the exploration of different areas of the brain such as the frontopolar cortex or the salience network and the use of biomarkers.

Unmet needs and harm reduction preferences of syringe services program participants: differences by co-use of illicit opioids and methamphetamine

BACKGROUND

The current fourth wave of the United States opioid overdose epidemic is characterized by the co-use of opioids and stimulants, including illicit opioids and methamphetamine. The co-use of these two drugs, known as "goofballing," is associated with higher risk for several adverse outcomes, including more frequent injections, greater health risks, and higher morbidity. Considering these differences, this unique subpopulation of people who inject drugs (PWID) may also have unique unmet needs and harm reduction preferences.

METHODS

We collected self-reported data from participants (N = 50) of a syringe services program (SSP), including basic needs and harm reduction preferences. Using bivariate analyses, we examined differences between SSP participants who do and do not co-use illicit opioids and methamphetamine. Co-use was defined as reporting the use of both drugs, which may or may not have been used simultaneously.

RESULTS

In the overall sample, the mean level of need was highest for bus passes or other transportation, a person who can help you get the services you need, medication for opioid use disorder, and a job or job training. Additionally, all participants reported being either interested or very interested in fentanyl test strips, safe consumption sites, delivery of syringe service supplies, and delivery of naloxone. Those who endorsed co-use had a greater need for food, healthcare, substance use disorder treatment, a support person to help them access needed services, and bus passes or transportation.

CONCLUSIONS

Unmet needs were prevalent, and the desire for more harm reduction services was high among these PWID. Results also suggest people who co-use illicit opioids and methamphetamine may have the greatest unmet needs and desire for additional harm reduction services.

In vitro structure-activity relationships and forensic case series of emerging 2-benzylbenzimidazole 'nitazene' opioids

2-Benzylbenzimidazole 'nitazene' opioids are presenting a growing threat to public health. Although various nitazenes were previously studied, systematic comparisons of the effects of different structural modifications to the 2-benzylbenzimidazole core structure on μ-opioid receptor (MOR) activity are limited. Here, we assessed in vitro structure-activity relationships of 9 previously uncharacterized nitazenes alongside known structural analogues. Specifically, we focused on MOR activation by 'ring' substituted analogues (i.e., N-pyrrolidino and N-piperidinyl modifications), 'desnitazene' analogues (lacking the 5-nitro group), and N-desethyl analogues. The results from two in vitro MOR activation assays (β-arrestin 2 recruitment and inhibition of cAMP accumulation) showed that 'ring' modifications overall yield highly active drugs. With the exception of 4'-OH analogues (which are metabolites), N-pyrrolidino substitutions were generally more favorable for MOR activation than N-piperidine substitutions. Furthermore, removal of the 5-nitro group on the benzimidazole ring consistently caused a pronounced decrease in potency. The N-desethyl modifications showed important MOR activity, and generally resulted in a slightly lowered potency than comparator nitazenes. Intriguingly, N-desethyl isotonitazene was the exception and was consistently more potent than isotonitazene. Complementing the in vitro findings and demonstrating the high harm potential associated with many of these compounds, we describe 85 forensic cases from North America and the United Kingdom involving etodesnitazene, N-desethyl etonitazene, N-desethyl isotonitazene, N-pyrrolidino metonitazene, and N-pyrrolidino protonitazene. The low-to-sub ng/mL blood concentrations observed in most cases underscore the drugs' high potencies. Taken together, by bridging pharmacology and case data, this study may aid to increase awareness and guide legislative and public health efforts.

"Coke in the Dope": The Underrecognized Complications of a Cocaine-Adulterated Fentanyl Supply

ABSTRACT

The opioid crisis, particularly the "fourth wave" involving fentanyl and stimulants, has been responsible for an alarming increase in overdose deaths in the United States. Although fentanyl contamination in cocaine has gained significant attention, the converse-cocaine-adulterated fentanyl-has been largely overlooked despite its health implications. The rise in concurrent cocaine and fentanyl overdose deaths could be attributed to various factors, from intentional polysubstance use to unintentional adulterations. Cocaine-related health issues may amplify the problem. Four potential pathways for the increased risk of overdose with cocaine-adulterated opioids include enhanced drug reinforcement, potential overdose risk with switching drug samples, altered metabolism of medications used for opioid use disorder, and increased myocardial demand juxtaposed with opioid-induced respiratory depression. With these risks, the importance of drug testing becomes paramount in the unregulated drug market. As polysubstance use overdoses surge, there is an urgent need to understand how drug supplies are changing in order to effectively identify appropriate harm reduction strategies. Specifically, further research is needed evaluating complications of low-level cocaine exposure with chronic/persistent opioid use. The hazards associated with cocaine-adulterated fentanyl emphasize the significance of understanding not only fentanyl's presence in cocaine but also cocaine's role in the fentanyl supply.

Co-administration of naloxone and dexmedetomidine to simultaneously reverse acute effects of fentanyl and methamphetamine in rats

BACKGROUND

The incidence of combination methamphetamine (METH)-opioid overdose has substantially increased in recent years. While agitation is uncommon after the naloxone (NLX) reversal of opioids, it is a major clinical concern in acute METH intoxication and can be physiologically antagonized by opioid-induced sedation. This study aimed to perform initial preclinical analysis of the safety and efficacy of dexmedetomidine (DEXMED) co-administered with NLX to attenuate METH-induced locomotor activity, as a rat model of agitation, after the reversal of fentanyl (FENT)-induced sedation.

METHODS

Male Sprague Dawley rats were administered subcutaneous (SC) 0.1mg/kg FENT ± 1mg/kg METH. Fifteen min later, SC 0.1mg/kg NLX ± an increasing (0, 0.032, 0.056, and 0.1mg/kg) DEXMED dose was administered prior to the measurement of locomotor activity. After a washout period, the FENT ± METH and NLX ± DEXMED administration with the highest dose of DEXMED was administered for measurement of blood oxygen saturation and heart rate.

RESULTS

After the NLX reversal of FENT-induced sedation, adjunct DEXMED substantially and significantly reduced METH-induced locomotor activity (p<0.05) at all doses tested. While the addition of DEXMED did not significantly reduce blood oxygenation in METH treated rats, it did so in the absence of METH. Also, DEXMED significantly reduced heart rate compared to non-DEXMED treated groups and resulted in further significant reductions in the animals not exposed to METH (p<0.05).

CONCLUSIONS

These data provide preclinical evidence that DEXMED may be a safe and effective chemical restraint for METH-induced agitation after NLX opioid reversal.

Changes in injecting versus smoking heroin, fentanyl, and methamphetamine among people who inject drugs in San Diego, California, 2020-2023

BACKGROUND

Amidst an increasingly toxic drug supply in North America, people who inject drugs may be transitioning to smoking them. We aimed to assess changes in injecting and smoking opioids and methamphetamine among a cohort of people who inject drugs from San Diego, California.

METHODS

Over five six-month periods spanning October 2020-April 2023, we assessed prevalence of injecting and smoking opioids or methamphetamine and whether participants used these drugs more frequently by smoking than injecting. Multivariable Poisson regression via generalized estimating equations was used to examine time trends.

RESULTS

Of 362 participants, median age was 40 years; a minority were female (29%), Hispanic/Latinx/Mexican (45%), and housed (33%). Among this cohort, of whom 100% injected (and 84% injected and smoked) in period one (October 2020-April 2021), by period five (November 2022-April 2023), 34% only smoked, 59% injected and smoked, and 7% only injected. By period five, the adjusted relative risk (aRR) of injecting opioids was 0.41 (95% Confidence Interval [CI]: 0.33, 0.51) and the aRR for injecting methamphetamine was 0.50 (95% CI: 0.39, 0.63) compared to period one. Risks for smoking fentanyl rose significantly during period three (aRR=1.44, 95% CI: 1.06, 1.94), four (aRR=1.65, 95% CI: 1.24, 2.20) and five (aRR=1.90, 95% CI: 1.43, 2.53) compared to period one. Risks for smoking heroin and methamphetamine more frequently than injecting these drugs increased across all periods.

CONCLUSIONS

Opioid and methamphetamine injection declined precipitously, with notable increases in smoking these drugs. Research is needed to understand the health consequences of these trends.

Implementation and evaluation of interprofessional overdose review team recommendations following intentional or accidental overdose events

Drug overdose death rates in the United States remain high despite efforts to mitigate this risk. Many communities and hospitals across the country have implemented overdose review teams, including local overdose fatality review teams or postoverdose intervention programs, to address the opioid crisis. The goal of most of these teams is to identify missed opportunities or patient-specific interventions to prevent future opioid overdose fatalities. Few overdose review teams review a combination of both fatal and nonfatal overdose events. The Veterans Affairs Tennessee Valley Healthcare System implemented a novel overdose review team (ORT) that collaboratively reviews all overdose incidents regardless of fatality, intent, or substance involved. This practice description characterizes reported facility overdose events and patient-specific risk-mitigation strategies recommended by the ORT, highlights the implementation rate and time to implementation of ORT recommendations, and discusses potential areas for process improvement. This practice highlights the potential impact of a pharmacist-led, interdisciplinary ORT following accidental or intentional overdose events involving any substance or medication. Key patient-specific interventions implemented following ORT recommendations included overdose prevention education and naloxone distribution, prescribing of medications for opioid use disorder and/or alcohol use disorder, reducing medication supply to limit lethal means access, and facilitation of mental health and/or substance use disorder specialty appointments. Further research to evaluate clinical outcomes related to specific ORT interventions should be considered.

Understanding and Addressing Widening Racial Inequalities in Drug Overdose

The fourth wave of the United States overdose crisis-driven by the polysubstance use of fentanyl with stimulants and other synthetic substances-has driven sharply escalating racial/ethnic inequalities in drug overdose death rates. Here the authors present a detailed portrait of the latest overdose trends and synthesize the literature to describe where, how, and why these inequalities are worsening. By 2022 overdose deaths among Native and Black Americans rose to 1.8 and 1.4 times the rate seen among White Americans, respectively. This reflects that Black and Native Americans have been disproportionately affected by fentanyl and the combination of fentanyl and stimulants at the national level and in virtually every state. The highest overdose deaths rates are currently seen among Black Americans 55-64 years of age as well as younger cohorts of Native Americans 25-44 years of age. In 2022-the latest year of data available-deaths among White Americans decreased relative to 2021, whereas rates among all other groups assessed continued to rise. Moving forward, Fundamental Cause Theory shows us a relevant universal truth of implementation science: in socially unequal societies, new technologies typically end up favoring more privileged groups first, thereby widening inequalities unless underlying social inequalities are addressed. Therefore, interventions designed to reduce addiction and overdose death rates that are not explicitly designed to also improve racial/ethnic inequalities will often unintentionally end up worsening them. Well-funded community-based programs, with Black and Native leadership, providing harm reduction resources, naloxone, and medications for opioid use disorder in the context of comprehensive, culturally appropriate healthcare and other services, represent the highest priority interventions to decrease inequalities.

Enantiomeric contributions to methamphetamine's bidirectional effects on basal and fentanyl-depressed respiration in mice

RATIONALE

Fentanyl remains the primary cause of fatal overdoses, and its co-use with methamphetamine (METH) is a growing concern. We previously demonstrated that racemic METH can either enhance or mitigate opioid-induced respiratory depression (OIRD) dependent upon whether a low or high dose is administered. The optical isomers of METH, dextromethamphetamine (d-METH) and levomethamphetamine (l-METH), differ substantially in their selectivity and potency to activate various monoamine (MA) receptors, and these pharmacological differences may underlie the bidirectional effects of the racemate. Since it is unknown which of METH's MA receptor mechanisms mediate these respiratory effects, examination of METH's pharmacologically distinct enantiomers may provide insight into treatment targets for OIRD.

METHODS

The two optical isomers of METH, d-METH and l-METH, were tested in adult male mice to determine their effects on basal and fentanyl-depressed respiratory frequency, tidal volume, and minute ventilation (MVb; i.e., respiratory frequency x tidal volume) using whole-body plethysmography.

RESULTS

When tested at dose ranges of 1.0-10 mg/kg, d-METH elevated MVb and l-METH decreased basal MVb. A dose of 30 mg/kg l-METH increased basal MVb. Under fentanyl-depressed conditions, the bidirectional effects of racemic METH were observed with d-METH treatment while l-METH significantly exacerbated OIRD at 1.0 and 3.0 mg/kg.

CONCLUSIONS

d-METH and l-METH differentially contribute to the bidirectional respiratory modulation observed by the racemate, with d-METH exhibiting predominantly stimulatory effects and l-METH exhibiting primarily depressant effects depending on dose.

Examining disparities in regional anaesthesia and pain medicine

In high-resource countries, health disparities exist in both treatment approaches and health outcomes. Race and ethnicity can serve as proxies for other socioeconomic factors and social determinants of health such as income, education, social support, and residential neighbourhood, which strongly influence health outcomes and disparities. In regional anaesthesia and pain medicine, disparities exist across several surgical specialties including obstetrics, paediatrics, and orthopaedic surgery. Understanding these disparities will facilitate development of solutions aimed at eliminating disparities at the patient, physician/provider, and healthcare system levels.

Prevalence of comorbid substance use disorders among people with opioid use disorder: A systematic review & meta-analysis

BACKGROUND

Comorbid substance use disorders (SUDs) among people with opioid use disorder (OUD) contribute to poor clinical outcomes, including overdose and mortality. We present the first systematic review and meta-analysis to estimate the prevalence of specific non-opioid SUDs among people with OUD.

METHODS

We searched Embase, PsycINFO, and MEDLINE from 1990 to 2022 for studies that used Diagnostic and Statistical Manual of Mental Disorders (DSM) or International Classification of Diseases (ICD) criteria to assess the prevalence of non-opioid SUDs among individuals with OUD. We used random-effects meta-analyses with 95% Confidence Intervals (CIs) to pool current and lifetime prevalence estimates separately. Meta-regressions and stratified meta-analyses were used to examine differences in prevalence estimates by sample characteristics and methodological factors.

RESULTS

Of the 36,971 publications identified, we included data from 194 studies and 77,212 participants with OUD. The prevalence of any comorbid SUD among people with OUD was 59.5% (95%CI 49.1-69.5%) for current non-opioid SUDs, with 72.0% (95%CI 52.5-87.9%) experiencing a comorbid SUD in their lifetime. Of the studies that examined current comorbid SUDs, cocaine use disorder (30.5%, 95%CI 23.0-38.7%) was most common, followed by alcohol (27.1%, 95%CI 24.4- 30.0%), cannabis (22.7%, 95%CI 19.0-26.6%), sedative (16.1%, 95%CI 13.1-19.3%), and methamphetamine (11.4%, 95%CI 6.8-17.1%) use disorders. Substantial heterogeneity (I2>90%) across estimates was observed. Substantial heterogeneity (I2>90%) was observed across estimates, with significant variations in prevalence identified across geographic locations, recruitment settings, and other study-level factors.

CONCLUSION

Findings from this study emphasize the importance of comorbid SUD treatment access for people with OUD. Our estimates can inform the provision of treatment and harm reduction strategies for people with OUD and specific subpopulations.

Trends in pediatric prescription-opioid overdoses in U.S. emergency departments from 2008-2020: An epidemiologic study of pediatric opioid overdose ED visits

BACKGROUND

Opioid overdose was declared a public health emergency in the United States, but much of the focus has been on adults. Child and adolescent exposure and access to unused prescription-opioid medications is a big concern. More research is needed on the trend of pediatric (age 0-17) prescription-opioid overdose emergency department (ED) visits in the United States, particularly during the COVID-19 pandemic year.

METHODS

This retrospective epidemiological study used the 2008-2020 Nationwide Emergency Department Sample to provide a national estimate of ED visits related to prescription-opioid overdose. Inclusion criteria were 0-17-year-old patients treated at the ED due to prescription-opioid overdose. Eligible visits were identified if their medical records included any administrative billing codes for prescription-opioid overdose. National estimates were broken down by age groups, sex, geographic region, primary payer, median household income by zip code, ED disposition, and hospital location/teaching status. Incidence rate per 100,000 U.S. children was calculated for age groups, sex, and geographic region.

RESULTS

Overall, the prescription-opioid overdose ED visits for patients from 0-17 years old in the United States decreased by 22% from 2008 to 2019, then increased by 12% in 2020. Most patients were discharged to home following their ED visit; however, there was a 42% increase in patients admitted from 2019 to 2020. The prescription-opioid overdose rate per 100,000 U.S. children was highest in the 0 to 1 and 12 to 17 age groups, with the 12 to 17 group increasing by 27% in 2020. ED visits in the West and Midwest saw prescription-opioid visits increase by 58% and 20%, respectively, from 2019-2020.

CONCLUSIONS

Prescription-opioid overdose ED visits among U.S. children and adolescents decreased over the past decade until 2019. However, there was a substantial increase in ED visits from 2019 to 2020, suggesting the potential impact due to the then-emerging COVID-19 pandemic. Findings suggest focusing on young children and adolescents to reduce further prescription-opioid overdoses in the United States.

Comparative effectiveness of extended release naltrexone and sublingual buprenorphine for treatment of opioid use disorder among Medicaid patients

Aims

To compare the real-world effectiveness of extended release naltrexone (XR-NTX) and sublingual buprenorphine (SL-BUP) for the treatment of opioid use disorder (OUD).

Design

An observational active comparator, new user cohort study.

Setting

Medicaid claims records for patients in New Jersey and California, 2016-2019.

Participants/Cases

Adult Medicaid patients aged 18-64 years who initiated XR-NTX or SL-BUP for maintenance treatment of OUD and did not use medications for OUD in the 90-days before initiation.

Comparators

New initiation with XR-NTX versus SL-BUP for the treatment of OUD.

Measurements

We examined two outcomes up to 180 days after medication initiation, 1) composite of medication discontinuation and death, and 2) composite of overdose and death.

Findings

Our cohort included 1,755 XR-NTX and 9,886 SL-BUP patients. In adjusted analyses, treatment with XR-NTX was more likely to result in discontinuation or death by the end of follow-up than treatment with SL-BUP: cumulative risk 76% (95% confidence interval [CI] 75%, 78%) versus 62% (95% CI 61%, 63%), respectively (risk difference 14 percentage points, 95% CI 13, 16). There was minimal difference in the cumulative risk of overdose or death by the end of follow-up: XR-NTX 3.8% (95% CI 2.9%, 4.7%) versus SL-BUP 3.3% (95% 2.9%, 3.7%); risk difference 0.5 percentage points, 95%CI -0.5, 1.5. Results were consistent across sensitivity analyses.

Conclusions

Longer medication retention is important because risks of negative outcomes are elevated after discontinuation. Our results support selection of SL-BUP over XR-NTX. However, most patients discontinued medication by 6 months indicating that more effective tools are needed to improve medication retention, particularly after initiation with XR-NTX, and to identify which patients do best on which medication.

Paths Forward for Clinicians Amidst the Rise of Unregulated Clinical Decision Support Software: Our Perspective on NarxCare

Amidst the US overdose epidemic, policymakers, law enforcement agencies, and healthcare institutions have contributed to a decrease in opioid prescribing, assuming reduced mortality would result-an assumption we now understand was oversimplified. At this intersection between public health and public safety domains as they relate to opioid prescribing, unregulated and proprietary clinical decision support tools have emerged without rigorous external validation or public data sharing. In the following piece, we discuss challenges facing clinicians practicing medicine amidst unregulated clinical decision support tools, using the case of Bamboo Health's NarxCare-a prescription drug monitoring program-based analytics platform marketed as a clinical decision support tool-that is already positioned to impact over 1 billion patient encounters annually. We argue that sufficient evidence does not yet exist to support NarxCare's wide implementation, and that clinical decision support tools like NarxCare have flourished in recent years due to a lack of federal regulatory oversight and shielding by their proprietary formulas, which have facilitated their unchecked and outsized influence on patient care. Finally, we suggest specific actions by federal regulatory agencies, healthcare institutions, individual clinicians, and researchers, as well as academic journals, to mitigate potential harms associated with unregulated clinical decision support tools.

Performance of Fentanyl Immunoassays in an ED Patient Population

BACKGROUND

Fentanyl is a synthetic opioid fueling the current opioid crisis in the United States. While emergency department (ED) visits due to opioid-related overdoses, injection complications, and withdrawals become increasingly more frequent, fentanyl is not detected in routine toxicology testing. We evaluated 2 FDA-approved fentanyl immunoassays in a sampled ED population.

METHODS

De-identified, remnant urine specimens (n = 213) collected from patients presenting to a large ED were analyzed using ARK Fentanyl II (ARK II) and Immunalysis SEFRIA (SEFRIA) fentanyl immunoassays on an Architect c16000 (Abbott) analyzer. All discrepant specimens were evaluated by LC-MS/MS. Additionally, polysubstance abuse patterns and trends were analyzed.

RESULTS

While intra-assay imprecision was comparable for ARK II and SEFRIA, inter-assay imprecision for ARK II and SEFRIA varied from 8.0% to 1.8% and from 37% to 12.5%, respectively. SEFRIA had a marginally higher false-positivity rate (3%) than ARK II (1%). Both assays had equivalent sensitivity of 95%, with ARK II (99%) having greater specificity than SEFRIA (97%). Fentanyl was detected in 13.7% of drug-panel-positive patient samples and most frequently observed in patients also testing positive for amphetamines and cocaine. Notably, fentanyl was detected in 5.3% of patient samples that were negative for all other drugs in our standard toxicology panel.

CONCLUSIONS

A sizable portion of drug-positive samples from our ED were positive for fentanyl, with a subset of patients testing positive for fentanyl alone. Implementation of fentanyl testing into routine toxicology panels can elucidate polysubstance abuse paradigms and capture ED patients that would go undetected in standard panels.

Sexually transmitted and blood-borne infection risk reduction with methadone and buprenorphine/naloxone among people with prescription-type opioid use disorder: Findings from a Canadian pragmatic randomized trial

INTRODUCTION

People who use drugs are disproportionally affected by sexually transmitted and blood-borne infections (STBBIs). While the benefits of methadone in reducing injecting-risk behaviours are well documented, less is known on its impacts on sexual-related risks, as well as its comparative effectiveness to buprenorphine/naloxone, particularly in the context of highly potent opioids. The aim of this study was to estimate the relative effects of buprenorphine/naloxone and methadone on injecting and STBBI risks among people with prescription-type opioid use disorder (POUD).

METHODS

Secondary analysis of a pan-Canadian pragmatic 24-week randomized clinical trial comparing methadone and buprenorphine/naloxone models of care among 272 people with POUD (including licit or illicit opioid analgesics, fentanyl). The Risk Behaviour Survey was used to collect injecting and sexual risks at baseline, and weeks 12 and 24.

RESULTS

In total, 210 participants initiated treatment (103 buprenorphine/naloxone and 107 methadone). At baseline, 113/205 (55.1%) participants reported recently injecting drugs, 37/209 (17.7%) unsafe injection practices and 67/162 (41.4%) high-risk sex. Both methadone and buprenorphine/naloxone were associated with reductions in the prevalence of injection drug use and high-risk sex at weeks 12 and 24 with no interactions between treatment arm and time.

CONCLUSION

Methadone and buprenorphine/naloxone were similarly effective in reducing injecting and sexual risk behaviours among people with POUD.

CLINICAL TRIALS REGISTRATION

clinicaltrials.gov NCT03033732.

Changes in injecting versus smoking heroin, fentanyl, and methamphetamine among people who inject drugs in San Diego, California, 2020 to 2023

Background

Amidst a rapidly evolving drug supply in North America, people who inject drugs may be transitioning to smoking them. We aimed to assess changes in injecting and smoking heroin, fentanyl and methamphetamine among a cohort of people who injected drugs at baseline from San Diego, California.

Methods

Over five six-month periods spanning October 2020-April 2023, we assessed prevalence of injecting and smoking opioids or methamphetamine and whether participants used these drugs more frequently by smoking than injecting. Multivariable Poisson regression via Generalized Estimating Equations was used to examine time trends.

Results

Of 362 participants, median age was 40 years; most were male (72%), non-Hispanic (55%), and unhoused (67%). Among this cohort, of whom 100% injected (or injected and smoked) at baseline, by period five (two years later), 34% reported only smoking, while 59% injected and smoked, and 7% only injected. By period five, the adjusted relative risk (aRR) of injecting opioids was 0.41 (95% Confidence Interval [CI]: 0.33, 0.51) compared to period one, and the aRR for injecting methamphetamine was 0.50 (95% CI: 0.39, 0.63). Compared to period one, risks for smoking fentanyl rose significantly during period three (aRR=1.44, 95% CI: 1.06, 1.94), four (aRR=1.65, 95% CI: 1.24, 2.20) and five (aRR=1.90, 95% CI: 1.43, 2.53). Risks for smoking heroin and methamphetamine more frequently than injecting these drugs increased across all periods.

Conclusions

Opioid and methamphetamine injection declined precipitously, with notable increases in smoking these drugs. Research is urgently needed to understand the health consequences of these trends.

Series of (([1,1'-Biphenyl]-2-yl)methyl)sulfinylalkyl Alicyclic Amines as Novel and High Affinity Atypical Dopamine Transporter Inhibitors with Reduced hERG Activity

Currently, there are no FDA-approved medications for the treatment of psychostimulant use disorders (PSUD). We have previously discovered "atypical" dopamine transporter (DAT) inhibitors that do not display psychostimulant-like behaviors and may be useful as medications to treat PSUD. Lead candidates (e.g., JJC8-091, 1) have shown promising in vivo profiles in rodents; however, reducing hERG (human ether-à-go-go-related gene) activity, a predictor of cardiotoxicity, has remained a challenge. Herein, a series of 30 (([1,1'-biphenyl]-2-yl)methyl)sulfinylalkyl alicyclic amines was synthesized and evaluated for DAT and serotonin transporter (SERT) binding affinities. A subset of analogues was tested for hERG activity, and the IC50 values were compared to those predicted by our hERG QSAR models, which showed robust predictive power. Multiparameter optimization scores (MPO > 3) indicated central nervous system (CNS) penetrability. Finally, comparison of affinities in human DAT and its Y156F and Y335A mutants suggested that several compounds prefer an inward facing conformation indicating an atypical DAT inhibitor profile.

Impact of Potential Case Misclassification by Administrative Diagnostic Codes on Outcome Assessment of Observational Study for People Who Inject Drugs

Introduction

Initiation of medications for opioid use disorder (MOUD) within the hospital setting may improve outcomes for people who inject drugs (PWID) hospitalized because of an infection. Many studies used International Classification of Diseases (ICD) codes to identify PWID, although these may be misclassified and thus, inaccurate. We hypothesized that bias from misclassification of PWID using ICD codes may impact analyses of MOUD outcomes.

Methods

We analyzed a cohort of 36 868 cases of patients diagnosed with Staphylococcus aureus bacteremia at 124 US Veterans Health Administration hospitals between 2003 and 2014. To identify PWID, we implemented an ICD code-based algorithm and a natural language processing (NLP) algorithm for classification of admission notes. We analyzed outcomes of prescribing MOUD as an inpatient using both approaches. Our primary outcome was 365-day all-cause mortality. We fit mixed-effects Cox regression models with receipt or not of MOUD during the index hospitalization as the primary predictor and 365-day mortality as the outcome.

Results

NLP identified 2389 cases as PWID, whereas ICD codes identified 6804 cases as PWID. In the cohort identified by NLP, receipt of inpatient MOUD was associated with a protective effect on 365-day survival (adjusted hazard ratio, 0.48; 95% confidence interval, .29-.81; P < .01) compared with those not receiving MOUD. There was no significant effect of MOUD receipt in the cohort identified by ICD codes (adjusted hazard ratio, 1.00; 95% confidence interval, .77-1.30; P = .99).

Conclusions

MOUD was protective of all-cause mortality when NLP was used to identify PWID, but not significant when ICD codes were used to identify the analytic subjects.

Health risks associated with smoking versus injecting fentanyl among people who use drugs in California

BACKGROUND

Given the attention, funding, and services that seek to reduce overdose mortality from fentanyl, it is important to understand whether a potential solution is for more people to switch from injecting to smoking fentanyl. As such, we set out to conduct a study to compare health and healthcare utilization outcomes associated with different modes of illicit fentanyl administration.

METHODS

From January to February 2023, we recruited people who use drugs from 34 syringe services programs across California, USA (N=999) and surveyed their substance use, health outcomes, and healthcare utilization. We compared health risks among people who injected fentanyl (78% of whom also smoked) to people who solely smoked fentanyl (n=563).

RESULTS

Of the 563 participants, forty-one percent injected fentanyl and 59% only smoked fentanyl. People who injected fentanyl were 40% more likely to have experienced a non-fatal overdose in the past 3 months (27% vs. 19%; aRR=1.40; 95% CI=1.03, 1.93) and 253% more likely to have had a skin and soft tissue infection in the past 3 months (39% vs. 15%; aRR=2.53; 95% CI=1.74, 3.67), compared to people who only smoked fentanyl. The average number of nights spent in the hospital was higher among people who injected fentanyl (average 1.2 nights vs. 0.7 nights; aIRR=1.78; 95% CI=1.02, 3.09; p=0.04).There were non-significant associations between mode of fentanyl administration and number of emergency department visits and probability of hospitalization.

CONCLUSIONS

Findings suggested that people who injected fentanyl were at higher risk for overdose and skin and soft tissue infections than people who only smoked fentanyl. Distribution of safe smoking supplies may facilitate transitions from injecting to smoking fentanyl, thereby reducing health risks associated with fentanyl use.

Vaccines to Treat Substance Use Disorders: Current Status and Future Directions

Addiction, particularly in relation to psychostimulants and opioids, persists as a global health crisis with profound social and economic ramifications. Traditional interventions, including medications and behavioral therapies, often encounter limited success due to the chronic and relapsing nature of addictive disorders. Consequently, there is significant interest in the development of innovative therapeutics to counteract the effects of abused substances. In recent years, vaccines have emerged as a novel and promising strategy to tackle addiction. Anti-drug vaccines are designed to stimulate the immune system to produce antibodies that bind to addictive compounds, such as nicotine, cocaine, morphine, methamphetamine, and heroin. These antibodies effectively neutralize the target molecules, preventing them from reaching the brain and eliciting their rewarding effects. By obstructing the rewarding sensations associated with substance use, vaccines aim to reduce cravings and the motivation to engage in drug use. Although anti-drug vaccines hold significant potential, challenges remain in their development and implementation. The reversibility of vaccination and the potential for combining vaccines with other addiction treatments offer promise for improving addiction outcomes. This review provides an overview of anti-drug vaccines, their mechanisms of action, and their potential impact on treatment for substance use disorders. Furthermore, this review summarizes recent advancements in vaccine development for each specific drug, offering insights for the development of more effective and personalized treatments capable of addressing the distinct challenges posed by various abused substances.

Baseline Characteristics and Postdischarge Outcomes by Medication for Opioid Use Disorder Status Among Women with Polysubstance Use in Residential Treatment

Background

Within residential treatment, medication for opioid use disorder (MOUD) is rarely offered, so little is known about group differences by MOUD status. This study characterizes samples of women receiving and not receiving MOUD and explores postdischarge outcomes.

Methods

This is a secondary exploratory analysis of a residential clinical trial comparing women receiving treatment as usual (TAU) with those who also received computer-based training for cognitive behavioral therapy (CBT4CBT). Participants were N = 41 adult women with substance use disorder (SUD) who self-reported lifetime polysubstance use. Because 59.0% were prescribed MOUD (MOUD n = 24, no MOUD n = 17), baseline variables were compared by MOUD status; outcomes at 12 weeks postdischarge were compared by MOUD status and treatment condition using chi square and Mann-Whitney U tests.

Results

Participants were middle-aged (41.7 ± 11.6 years) and non-Latinx Black (80.4%). Most used substances in the No MOUD group were alcohol, cocaine, and cannabis, and in the MOUD group, most used substances were opioids, cannabis, and cocaine. Women in the MOUD group tended to have more severe SUD. Postdischarge substance use recurrence rates were twice as high in the MOUD group than in the No MOUD group. Among the women in the No MOUD group, those in the CBT4CBT condition increased the number of coping strategies twice as much as those receiving TAU.

Conclusion

Postdischarge substance use recurrence differed by MOUD status. CBT4CBT may be a helpful adjunct to personalized residential SUD treatment. The parent study is registered at [www.clinicaltrials.gov (ClinicalTrials.gov identifier: NCT03678051)].

Gabapentinoids in Ireland 2010 to 2020: An observational study of trends in gabapentinoid prescribing, law enforcement drug seizures and postmortem toxicology

AIMS

We explored trends in gabapentinoid prescribing, drug seizures and postmortem toxicology using a national pharmacy claims database, law enforcement drug seizures data and a population-based postmortem toxicology database.

METHODS

Gabapentinoid prescribing rates per 100 000 eligible population (2010-2020), annual number of drug seizures involving gabapentinoids (2012-2020) and gabapentinoid detection (positive) rates per 100 postmortem toxicology case (2013-2020) were calculated. Negative binomial regression models were used to evaluate longitudinal trends for gabapentin and pregabalin separately.

RESULTS

Gabapentin (adjusted rate ratio [RR] 1.06, 95% confidence interval [CI] 1.05-1.06, P < .001) and pregabalin (adjusted RR 1.08, 95% CI 1.08-1.09, P < .001) prescribing increased annually, with higher rates of pregabalin (vs. gabapentin) observed every year. Drug seizures involving pregabalin also increased over time (RR 1.54 95% CI 1.25-1.90, P < .0001). Of the 26 317 postmortem toxicology cases, 0.92% tested positive for gabapentin, and 6.37% for pregabalin. Detection rates increased for both gabapentin (RR 1.28, 95% CI 1.11-1.48, P < .001) and pregabalin (RR 1.13, 95% CI 1.11-1.48, P < .001) between 2013 and 2020. A total of 1901 cases (7.2%) tested positive for heroin/methadone; this sub-group had a higher detection rate for pregabalin (n = 528, 27.8%) and gabapentin (n = 41, 2.2%) over the study period, with a high burden of codetections for pregabalin with benzodiazepines (peaking at 37.3% in 2018), and pregabalin with prescription opioids (peaking at 28.9% in 2020).

CONCLUSION

This study raises concerns regarding the wide availability of pregabalin in Ireland, including a growing illicit supply, and the potential for serious harm arising from poly drug use involving pregabalin among people who use heroin or methadone.