Xylazine spreads across the US: A growing component of the increasingly synthetic and polysubstance overdose crisis

Drug use practices and wound care experiences in the age of xylazine adulteration

INTRODUCTION

Exposure to xylazine has been associated with wounds distinct from typical injection-related skin and soft tissue infections. We sought to understand drug use and wound care practices, and treatment experiences of people who use drugs (PWUD) in a high-prevalence area of xylazine adulteration.

METHODS

In August 2023, we surveyed adult PWUD reporting at least one past-year drug use-related wound across three Massachusetts syringe service programs. Using a representative illustration, participants indicated if they had experienced a xylazine wound in the past 90 days. We compared demographic, drug use factors, wound care, and medical treatment experiences among those with and without xylazine wounds. We also conducted additional content analysis of open-ended responses.

RESULTS

Of the 171 respondents, 87 % (n=148) had a xylazine wound in the past 90 days. There were no statistically significant demographic differences between those with and without xylazine wounds. Among those primarily injecting (n=155), subcutaneous injection was nearly ten times more likely among people with xylazine wounds. For those with xylazine wounds (n=148), many engaged in heterogeneous wound self-treatment practices, and when seeking medical care, 74 % experienced healthcare stigma and 58 % had inadequate pain and withdrawal management.

CONCLUSION

People with self-identified xylazine wounds were more likely to engage in subcutaneous injection and faced several barriers seeking medical wound treatment. Programs serving people exposed to xylazine should work to support safer injection practices, including alternatives to injecting and improving access to high-quality, effective wound care. Further study is warranted to understand the causes, promoters, and prevention of xylazine-related wounds.

Opportunities and challenges for implementing drug checking services in British Columbia, Canada: A qualitative study

BACKGROUND

Amidst the ongoing drug poisoning crisis across North America, drug checking services (DCS) are increasingly being implemented as an intervention intended to reduce drug-related harms. This study sought to identify key opportunities and challenges influencing the implementation of DCS in British Columbia (BC), Canada.

METHODS

Between January 2020 and July 2021, semi-structured, in-depth interviews were conducted with 21 individuals involved in the implementation of DCS across BC (i.e., policymakers, health authority personnel, community organization representatives and service providers). The Consolidated Framework for Implementation Research (CFIR) was used to guide coding and analysis of the interviews.

RESULTS

By bringing in a wealth of knowledge about community needs and concerns, in addition to a passion and energy for social justice and health equity, community members and organizations with a dedication for harm reduction played a critical role in the successful implementation of DCS in BC. Other significant facilitators to implementation included the preventive benefits of DCS that made the intervention compelling to policy influencers and decision makers, the provincial public health emergency regarding overdose that shifted the regulatory environment of DCS, the adaptability of DCS to meet concerns and needs in various contexts, including via ongoing processes of reflection and evaluation. Barriers to implementation included criminalization and stigmatization of drug use and people who use drugs and lack of funding for community-led implementation actions.

CONCLUSIONS

Alongside structural reforms that address the underlying contextual factors that influence implementation (e.g., decriminalization of drugs, increased funding for DCS), centering community expertise throughout implementation is critical to the success of DCS. Our findings provide important insights into how BC can successfully implement systems-level harm reduction interventions and offer insights for other jurisdictions in their implementation of DCS.

Decrease in injection and rise in smoking and snorting of heroin and synthetic opioids, 2000-2021

BACKGROUND

Injecting, smoking, and snorting heroin/synthetic opioids is each associated with unique health risks. It is unclear how route of administration (ROA) preferences have shifted during the opioid epidemic.

METHODS

Using 2000-2021 admissions data from SAMHSA TEDS-A, we analyzed trends in heroin/synthetic opioid ROA preferences and factors associated with these preferences.

RESULTS

7,881,318 heroin/synthetic opioid admissions reported injection, smoking, or snorting preference. Nationally, injection peaked in 2014 (69.9 %) and nadired in 2021(52.2 %), snorting nadired in 2014 (24.9 %) and peaked in 2021 (36.4 %), and smoking rose steadily from 2.5 % in 2005 to a peak of 11.4 % in 2021. From 2000-2021, the number of states with ≥10 % smoking rates grew from 2 to 27 (highest: 57.0 % in Arizona in 2021). In 2021, increased adjusted prevalence ratios (APR) of non-injection versus injection use were associated with older age at first opioid use (APR 1.52 [95 % CI: 1.51, 1.54] for those 30+ relative to ≤20), and all race/ethnicities relative to non-Latino White individuals (highest: Black individuals, APR 1.77 [1.75, 1.78]). Geography strongly predicted smoking versus snorting (Mountain APR 6.91 [6.64, 7.19], Pacific APR 6.61 [6.35, 6.88], reference: New England).

CONCLUSIONS

ROA preferences of heroin/synthetic opioids have changed substantially since 2000, with: 1) recent decreases in injection nationally; 2) increased smoking, particularly in the western US; and, 3) recent increased snorting in the eastern US. Smoking is now prevalent and growing. Public health implications include an increasing number of smoking-related fatal overdoses and the probable reduction of injection-specific morbidity and increase in smoking-specific morbidity.

Personal Experiences With Xylazine and Behavior Change: A Qualitative Content Analysis of Reddit Posts

OBJECTIVES

Xylazine is a rapidly spreading adulterant in the United States' drug supply and is increasingly associated with overdoses and severe wounds, but there is a dearth of information about the clinical presentation or means of treatment for human xylazine exposure. The objective of this study was to explore personal attitudes about xylazine in the drug supply and experiences with xylazine-related use among people who reported using drugs and contributed content to social media site Reddit.

METHODS

To conduct a retrospective qualitative content analysis, the study team extracted all posts and comments from Reddit, which mentioned the terms "xylazine" or "tranq." Content was extracted from 10 Reddit forums, or subreddits, specific to drug use, and included content created on or before the extraction date of January 2023. In total, 3284 posts were identified and 1803 were qualitatively coded using an inductive approach until meaning saturation was reached.

RESULTS

Three themes emerged across comments and posts: (1) personal experiences with xylazine, including a negative impact on overdose, withdrawal, and wounds; (2) behavior changes in response to xylazine in the drug supply, including devising and sharing new harm reduction and detection tips, and reducing or abstaining from drug use altogether; (3) a perceived lack of treatment options for xylazine withdrawal and information sharing to help others self-treat withdrawal symptoms, most often with clonidine.

CONCLUSIONS

This study of people who reported using drugs with xylazine provides new insights into how xylazine is perceived, possible treatment modalities, and potential clinical research approaches.

Early detection and prediction of non-fatal drug-related incidents and fatal overdose outbreaks using the Farrington algorithm

AIMS

The aim of this study was to assess the validity of undertaking time-series analyses on both fatal and non-fatal drug overdose outcomes for the surveillance of emerging drug threats, and to determine the validity of analyzing non-fatal indicators to support the early detection of fatal overdose outbreaks.

DESIGN, SETTING AND PARTICIPANTS

Time-series analyses using county-level data containing fatal overdoses and non-fatal overdose counts were collected at monthly intervals between 2015 and 2021 in California and Florida, USA. To analyze these data, we used the Farrington algorithm (FA), a method used to detect aberrations in time-series data such that an abnormal increase in counts relative to previous observations would result in an alert. The FA's performance was compared with a bench-mark approach, using the standard deviation as an aberration detection threshold. We evaluated whether monthly alerts in non-fatal overdose can aid in identifying fatal drug overdose outbreaks, defined as a statistically significant increase in the 6-month overdose death rate. We also conducted analyses across regions, i.e. clusters of counties.

MEASUREMENTS

Measurements were taken during emergency department and emergency medical service visits.

FINDINGS

Both methods yielded a similar proportion of alerts across scenarios for non-fatal overdoses, while the bench-mark method yielded more alerts for fatal overdoses. For both methods, the correlations between surveillance evaluations were relatively poor in the detection of aberrations (typically < 35%) but were high between evaluations yielding no alerts (typically > 75%). For ongoing fatal overdose outbreaks, a strategy based on the detection of alerts at the county level from either method yielded a sensitivity of 66% for both California and Florida. At the regional level, the equivalent analyses had sensitivities of 81% for California and 77% for Florida.

CONCLUSION

Aberration detection methods can support the early detection of fatal drug overdose outbreaks, particularly when methodologies are applied in combination rather than individual methods separately.

Community-Based Cluster-Randomized Trial to Reduce Opioid Overdose Deaths

BACKGROUND

Evidence-based practices for reducing opioid-related overdose deaths include overdose education and naloxone distribution, the use of medications for the treatment of opioid use disorder, and prescription opioid safety. Data are needed on the effectiveness of a community-engaged intervention to reduce opioid-related overdose deaths through enhanced uptake of these practices.

METHODS

In this community-level, cluster-randomized trial, we randomly assigned 67 communities in Kentucky, Massachusetts, New York, and Ohio to receive the intervention (34 communities) or a wait-list control (33 communities), stratified according to state. The trial was conducted within the context of both the coronavirus disease 2019 (Covid-19) pandemic and a national surge in the number of fentanyl-related overdose deaths. The trial groups were balanced within states according to urban or rural classification, previous overdose rate, and community population. The primary outcome was the number of opioid-related overdose deaths among community adults.

RESULTS

During the comparison period from July 2021 through June 2022, the population-averaged rates of opioid-related overdose deaths were similar in the intervention group and the control group (47.2 deaths per 100,000 population vs. 51.7 per 100,000 population), for an adjusted rate ratio of 0.91 (95% confidence interval, 0.76 to 1.09; P = 0.30). The effect of the intervention on the rate of opioid-related overdose deaths did not differ appreciably according to state, urban or rural category, age, sex, or race or ethnic group. Intervention communities implemented 615 evidence-based practice strategies from the 806 strategies selected by communities (254 involving overdose education and naloxone distribution, 256 involving the use of medications for opioid use disorder, and 105 involving prescription opioid safety). Of these evidence-based practice strategies, only 235 (38%) had been initiated by the start of the comparison year.

CONCLUSIONS

In this 12-month multimodal intervention trial involving community coalitions in the deployment of evidence-based practices to reduce opioid overdose deaths, death rates were similar in the intervention group and the control group in the context of the Covid-19 pandemic and the fentanyl-related overdose epidemic. (Funded by the National Institutes of Health; HCS ClinicalTrials.gov number, NCT04111939.).

A call for compassionate opioid overdose response

High dose and long-acting opioid overdose reversal drugs can precipitate withdrawal in people who are opioid dependent. Products recently brought to market for community use in the United States (US) have drawn international concern because of their increased risk of withdrawal. At the March 18-19, 2024, Compassionate Overdose Response Summit & Naloxone Dosing Meeting, a panel of harm reduction experts issued the following call to action: 1) people who use drugs should be directly involved in decisions regarding the research, development, selection, and distribution of opioid overdose reversal products; 2) regulatory agencies and pharmaceutical manufacturers should carefully consider and communicate the risk and duration of withdrawal associated with higher dose and longer-acting opioid antagonists; 3) take-home naloxone kits should include at least two doses of an intramuscular (IM) product containing 0.4 mg or an intranasal (IN) product containing ≤4 mg; 4) At this time, high dose and long-acting opioid antagonists have no use in acute opioid overdose response; and, 5) overdose response educational materials, instructions on overdose response, and training should emphasize the restoration of breathing, avoiding withdrawal, and compassionate post-overdose support and care. High dose and long-acting opioid overdose reversal drugs were approved without testing for withdrawal and are often aggressively marketed despite decades of evidence from naloxone distribution programs worldwide that the ideal dose of naloxone is one that restores breathing without inducing withdrawal. Government agencies should direct resources to harm reduction programs to make standard dose take-home naloxone products widely available among people who use drugs. Lay bystanders, people who use drugs, their families, and professional first responders can learn and apply a compassionate approach to opioid overdose response.

Improving Estimates of the Prevalence of Opioid Use Disorder in the United States: Revising Keyes et al

OBJECTIVES

The United States faces an ongoing drug overdose crisis, but accurate information on the prevalence of opioid use disorder (OUD) remains limited. A recent analysis by Keyes et al used a multiplier approach with drug poisoning mortality data to estimate OUD prevalence. Although insightful, this approach made stringent and partly inconsistent assumptions in interpreting mortality data, particularly synthetic opioid (SO)-involved and non-opioid-involved mortality. We revise that approach and resulting estimates to resolve inconsistencies and examine several alternative assumptions.

METHODS

We examine 4 adjustments to Keyes and colleagues' estimation approach: (A) revising how the equations account for SO effects on mortality, (B) incorporating fentanyl prevalence data to inform estimates of SO lethality, (C) using opioid-involved drug poisoning data to estimate a plausible range for OUD prevalence, and (D) adjusting mortality data to account for underreporting of opioid involvement.

RESULTS

Revising the estimation equation and SO lethality effect (adj. A and B) while using Keyes and colleagues' original assumption that people with OUD account for all fatal drug poisonings yields slightly higher estimates, with OUD population reaching 9.3 million in 2016 before declining to 7.6 million by 2019. Using only opioid-involved drug poisoning data (adj. C and D) provides a lower range, peaking at 6.4 million in 2014-2015 and declining to 3.8 million in 2019.

CONCLUSIONS

The revised estimation equation presented is feasible and addresses limitations of the earlier method and hence should be used in future estimations. Alternative assumptions around drug poisoning data can also provide a plausible range of estimates for OUD population.

Empirical assessment of wounds among people who use substances

BACKGROUND

Wounds are a significant source of morbidity among people who use substances (PWUS). This project sought to identify the incidence and severity of wounds among PWUS in the South Bronx, a region of New York City with one of the highest morbidities of substance use disorder.

METHODS

This study recruited PWUS within the past 30 days. Research staff were trained to document the presence and severity of wounds. The primary outcome measure was the incidence of wounds. Acceptability of on-the-street wound care was assessed by the number of participants encountered. The association between participant characteristics and wounds was also evaluated.

RESULTS

In total, 586 PWUS were assessed (19.4 % female: 69 % Hispanic; 23 % Black; 5 % White). Heroin (65.7 %) and psychostimulants (58.3 %) were the most commonly used drugs. Approximately 23 % of outreach recipients disclosed a wound. Among those with a wound, 60.9 % reported one wound, 27.8 % had two wounds, and 11.3 % had three or more wounds. Small wounds (approximately the size of a cherry) were the most common (78.6 %). Recent use of stimulants or heroin, along with intravenous use of any substance were significantly associated with having a wound.

CONCLUSIONS

This study found that drug-related wounds were common among PWUS. Toxicology data from other sources indicate that xylazine was present in the NYC market at the time, though its prevalence among the current sample is difficult to determine. The occurrence and severity of substance-related wounds in NYC should continue to be monitored as a function of changes in the xylazine adulteration.

Methadone Initiation in the Emergency Department for Opioid Use Disorder

Introduction

Overdose deaths from high-potency synthetic opioids, including fentanyl and its analogs, continue to rise along with emergency department (ED) visits for complications of opioid use disorder (OUD). Fentanyl accumulates in adipose tissue; although rare, this increases the risk of precipitated withdrawal in patients upon buprenorphine initiation. Many EDs have implemented medication for opioid use disorder (MOUD) programs using buprenorphine. However, few offer methadone, a proven therapy without the risk of precipitated withdrawal associated with buprenorphine initiation. We describe the addition of an ED-initiated methadone treatment pathway and compared its 72-hour follow-up outpatient treatment engagement rates to our existing ED-initiated buprenorphine MOUD program.

Methods

We expanded our ED MOUD program with a methadone treatment pathway. From February 20-September 19, 2023, we screened 20,504 ED arrivals; 5.1% had signs of OUD. We enrolled 61 patients: 28 in the methadone; and 33 in the buprenorphine pathways. For patients who screened positive for opioid use, shared decision-making was employed to determine whether buprenorphine or methadone therapy was more appropriate. Patients in the methadone pathway received their first dose of up to 30 milligrams (mg) of methadone in the ED. Two additional methadone doses of up to 40 mg were dispensed at the time of the ED visit and held in the department, allowing patients to return each day for observed dosing until intake at an opioid treatment program (OTP). We compared 72-hour rates of outpatient follow-up treatment engagement at the OTP (for those on methadone) or at the addiction treatment center (ATC) (for those on buprenorphine) for the two treatment pathways.

Results

Of the 28 patients enrolled in the methadone pathway, 12 (43%) successfully engaged in follow-up treatment at the OTP. Of the 33 patients enrolled in the buprenorphine pathway, 15 (45%) successfully engaged in follow-up treatment at the ATC (relative risk 1.06; 95% confidence interval 0.60-1.87).

Conclusion

Methadone initiation in the ED to treat patients with OUD resulted in similar 72-hour follow-up outpatient treatment engagement rates compared to ED-buprenorphine initiation, providing another viable option for MOUD.

Syringe services program staff and participant perspectives on changing drug consumption behaviors in response to xylazine adulteration

BACKGROUND

Xylazine is an increasingly common adulterant in the North American unregulated drug supply that is associated with adverse health outcomes (e.g., skin infections, overdose). However, there are significant knowledge gaps regarding how xylazine was initially identified and how syringe services program (SSP) staff and clients (people who use drugs) responded to its emergence.

METHODS

From June-July 2023, we conducted qualitative interviews with medical (e.g., clinicians) and frontline SSP staff (e.g., outreach workers) and adult clients with a history of injection drug use at a Miami-based SSP. Inductive memos identified emergent codes; thematic analysis involving team consensus established final themes.

RESULTS

From interviews with SSP staff (n = 8) and clients (n = 17), xylazine emergence was identified at different times, in various ways. Initially, during summer 2022, clients identified a "tranquilizer-like substance" that worsened sedation and withdrawal and caused wounds. SSP medical staff later identified this adulterant as xylazine by treating new medical cases and through diverse information-sharing networks that included professional societies and news sources; however, frontline SSP staff and clients needed additional educational resources about xylazine and its side effects. With limited guidance on how to reduce harm from xylazine, SSP clients altered their drug consumption routes, reduced drug use, and relied on peers' experiences with the drug supply to protect themselves. Some individuals also reported preferring xylazine-adulterated opioids and increasing their drug use, including the use of stimulants to avoid over sedation.

CONCLUSIONS

Xylazine's emergence characterizes the current era of unprecedented shifts in the unregulated drug supply. We found that xylazine spurred important behavioral changes among people who use drugs (e.g., transitioning from injecting to smoking). Incorporating these experiences into early drug warning surveillance systems and scaling up drug-checking services and safer smoking supply distribution could help mitigate significant health harms caused by xylazine and other emergent adulterants.

Evolution of the substance use landscape: Implications for contingency management

Contingency management (CM), which involves the delivery of incentives upon meeting behavioral goals, has the potential to improve substance use treatment outcomes. The intervention allows for flexibility through numerous modifiable components including changes to incentive magnitude and schedule, target behavior, and intervention structure. Unfortunately, numerous changes in the substance use landscape have occurred in the past 10 to 15 years: Substances are more potent, overdose risk has increased, new substances and methods of use have been introduced, and substance classes are increasingly being intentionally and unintentionally mixed. These developments potentially undermine CM outcomes. We explored recent substance use changes due to legislative, regulatory, social, and economic factors for four substance classes: stimulants, opioids, tobacco, and cannabis. We discuss potential adjustments to the modifiable components of CM for future research in response to these changes. By continually adapting to the shifting substance use landscape, CM can maintain optimal efficacy.

Analytical methods for the determination of xylazine in pharmaceutical, clinical and forensic matrices - A review

Xylazine, a non-opioid veterinary anaesthetic tranquillizer that is not licensed for human use, has been linked to an increase in overdose fatalities worldwide. The study delves into the forensic aspects of xylazine usage, emphasizing on chemical, clinical and toxicological analyses of drug seizures, bodily fluids and tissues. It advocates for validated analytical methods for determining xylazine. This study provides supporting material to pave the path for the usage and development of relevant and verified alternative screening and confirmation methods for laboratories. Google Scholar, Scopus, Science Direct and PubMed were searched for relevant articles and case reports in relation to xylazine misuse and established analytical methods for forensic investigation until April 2023. A total of 79 articles were evaluated, and 40 publications met the inclusion criteria. The most prevalent xylazine exposures recorded were incidental and intentional misuse/abuse. Common symptoms upon presentation were hypotension, bradycardia, drowsiness and lethargy, although mortality was less prevalent. Solid-phase extraction and liquid-liquid extraction are two extensively used sample preparation techniques. These techniques are used to extract desired analytes from complex matrices. Several analytical techniques have been stated, including GC-MS, LC-MS/MS, HPLC-DAD and others. The analytical procedures used are determined by the matrices involved, the amount of xylazine present, interfering compounds, the degree of precision required and the laboratory infrastructure. In the present context, the LC-MS/MS methods are preferred as the gold standard. In the near future, many analytical techniques such as capillary electrophoresis, PSI-MS, immuno-analytical techniques and SERRS may show significant potential.

Management of Xylazine-Induced Soft-Tissue Necrosis: A Review of 20 Cases

PURPOSE

The illicit injection of xylazine has recently been designated as an emerging public health threat. The use of this drug is associated with devastating soft-tissue necrosis that may lead to limb amputation. This study aimed to (1) report cases of soft-tissue injury from xylazine and (2) describe a staging and management algorithm for wounds related to xylazine use.

METHODS

A retrospective review was conducted to identify patients treated for xylazine-related soft-tissue necrosis at a trauma center. Clinical cases, treatment strategy, and available outcomes were presented. In addition, a comprehensive literature search was conducted using the keywords "xylazine" and "soft tissue."

RESULTS

The management of seven patients with xylazine-related upper extremity soft-tissue necrosis was included, in addition to summarizing findings of five studies reporting on 13 additional cases. These cases were managed with local wound care (2 patients), soft-tissue reconstruction (4 patient), osseous reconstruction (1 patient), and limb amputation (10 patients).

DISCUSSION

Acute treatment of xylazine-related soft-tissue necrosis is ideal to minimize morbidity and prevent limb loss. Management strategies of these wounds should be based on the depth of tissue involvement. Superficial ulceration involving the skin and subcutaneous tissue (Stage 1) should be managed with local wound care. Deeper ulceration involving tendons and/or muscle (Stage 2) requires surgical débridement and soft-tissue reconstruction. Deeper ulceration involving bone (Stage 3) requires osseous débridement and reconstruction. Finally, when all tissues in the extremity are involved (Stage 4), amputation is often necessary.

The Detection of Xylazine in Tijuana, Mexico: Triangulating Drug Checking and Clinical Urine Testing Data

Introduction

Xylazine is a veterinary anesthetic increasingly present alongside illicit fentanyl in the US and Canada, presenting novel health risks. Although xylazine remains less common in the Western US, Mexican border cities serve as key trafficking hubs and may have higher prevalence of novel substances, but surveillance has been limited.

Methods

We examined deidentified records from the Prevencasa harm reduction clinic in Tijuana, describing urine and paraphernalia testing from patients reporting using illicit opioids within 24 hr. Xylazine (two types), fentanyl, opiate, methamphetamine, amphetamine, benzodiazepine, and nitazene test strips were used to test urine and paraphernalia samples. Paraphernalia samples were also analyzed with mass spectrometry.

Results

The study consisted of 23 participants that provided both urine and paraphernalia samples. Of the participants studied, 100 %, 91.3 %, and 69.6 % reported using China White/fentanyl, methamphetamine, and tar heroin, respectively. The mean age was 41.7 years, 95.7 % were male, 65.2 % were unhoused, and 30.4 % had skin wounds at the time of sample collection.Xylazine positivity in urine, for the two types used, was 82.6 % and 65.2 %. For paraphernalia testing, the xylazine positivity was 65.2 % and 47.8 %. Confirmatory testing of paraphernalia samples by mass spectrometry indicated a 52.2 % xylazine positivity. This testing also revealed positivity rates for fentanyl (73.9 %), fluorofentanyl (30.4 %), tramadol (30.4 %), and lidocaine (30.4 %).The mass spectrometry results suggest lidocaine triggered n = 3 and n = 0 false positives among the xylazine test strip types. A total of n = 0 and n = 1 false negatives were also observed.

Discussion

Xylazine is present on the U.S.-Mexico border, requiring public health intervention. High lidocaine positivity complicates the clinical detection of xylazine via testing strips. Xylazine was found to be more prevalent in urine than in paraphernalia samples. Confirmatory urine studies are needed to better understand possible complications of using test strips for toxicological testing.

Protective or potentially harmful? Altering drug consumption behaviors in response to xylazine adulteration

Background

Xylazine is an increasingly common adulterant in the North American unregulated drug supply that is associated with adverse health outcomes (e.g., skin infections, overdose). However, there are significant knowledge gaps regarding how xylazine was initially identified and how syringe services program (SSP) staff and clients (people who use drugs) responded to its emergence.

Methods

From June-July 2023, we conducted qualitative interviews with medical (e.g., clinicians) and frontline SSP staff (e.g., outreach workers) and adult clients with a history of injection drug use at a Miami-based SSP. Inductive memos identified emergent codes; thematic analysis involving team consensus established final themes.

Results

From interviews with SSP staff (n = 8) and clients (n = 17), xylazine emergence was identified at different times, in various ways. Initially, during summer 2022, clients identified a "tranquilizer-like substance" that worsened sedation and withdrawal and caused wounds. SSP medical staff later identified this adulterant as xylazine by treating new medical cases and through diverse information-sharing networks that included professional societies and news sources; however, frontline SSP staff and clients needed additional educational resources about xylazine and its side effects. With limited guidance on how to reduce harm from xylazine, SSP clients altered their drug consumption routes, reduced drug use, and relied on peers' experiences with the drug supply to protect themselves. Some individuals also reported preferring xylazine-adulterated opioids and increasing their drug use, including the use of stimulants to avoid over sedation.

Conclusions

Xylazine's emergence characterizes the current era of unprecedented shifts in the unregulated drug supply. We found that xylazine spurred important behavioral changes among people who use drugs (e.g., transitioning from injecting to smoking). Incorporating these experiences into early drug warning surveillance systems and scaling up drug-checking services and safer smoking supply distribution could help mitigate significant health harms caused by xylazine and other emergent adulterants.

Oxygen fluctuations in the brain and periphery induced by intravenous fentanyl: effects of dose and drug experience

Fentanyl is the leading contributor to drug overdose deaths in the United States. Its potency, rapid onset of action, and lack of effective reversal treatment make the drug much more lethal than other opioids. Although it is understood that fentanyl is dangerous at higher doses, the literature surrounding fentanyl's physiological effects remains contradictory at lower doses. To explore this discrepancy, we designed a study incorporating electrochemical assessment of oxygen in the brain (nucleus accumbens) and subcutaneous space, multisite thermorecording (brain, skin, muscle), and locomotor activity at varying doses of fentanyl (1.0, 3.0, 10, 30, and 90 µg/kg) in rats. In the nucleus accumbens, lower doses of fentanyl (3.0 and 10 µg/kg) led to an increase in oxygen levels while higher doses (30 and 90 µg/kg) led to a biphasic pattern, with an initial dose-dependent decrease followed by an increase. In the subcutaneous space, oxygen decreases started to appear at relatively lower doses (>3 µg/kg), had shorter onset latencies, and were stronger and prolonged. In the temperature experiment, lower doses of fentanyl (1.0, 3.0, and 10 µg/kg) led to an increase in brain, skin, and muscle temperatures, while higher doses (30 and 90 µg/kg) resulted in a dose-dependent biphasic temperature change, with an increase followed by a prolonged decrease. We also compared oxygen and temperature responses induced by fentanyl over six consecutive days and found no evidence of tolerance in both parameters. In conclusion, we report that fentanyl's effects are highly dose-dependent, drawing attention to the importance of better characterization to adequately respond in emergent cases of illicit fentanyl misuse.NEW & NOTEWORTHY By using electrochemical oxygen sensors in freely moving rats, we show that intravenous fentanyl induces opposite changes in brain oxygen at varying doses, increasing at lower doses (<10 µg/kg) and inducing a biphasic response, decrease followed by increase, at higher doses (>10-90 µg/kg). In contrast, fentanyl-induced dose-dependent oxygen decreases in the subcutaneous space. We consider the mechanisms underlying distinct oxygen responses in the brain and periphery and discuss naloxone's role in alleviating fentanyl-induced brain hypoxia.

Exploring the harm reduction paradigm: the role of Board-Certified Psychiatric Pharmacists

Deaths related to opioid overdoses continue to climb, and there remains a need for innovative strategies to address this ongoing crisis. Harm reduction (HR), a nonjudgmental philosophy aimed at reducing consequences associated with drug use and other potentially unsafe behavior, has emerged as a compassionate and effective approach. Harm reduction further emphasizes overdose prevention and fosters a shift in perspective that recognizes substance use disorder as a disease and not a moral failing. The tenets of HR collectively advocate for the well-being of individuals who use substances and support any positive change as defined by the individual. Given the high rate of morbidity and mortality associated with substance misuse and barriers or ambivalence to receiving treatment, awareness of and advocacy for HR practice is essential. This manuscript aims to describe evidence-based HR interventions, provide a foundation for the implementation of services, and further promote the importance of providing humanistic care without judgment. As valued members of the multidisciplinary treatment team, Board-Certified Psychiatric Pharmacists should implement and engage in HR services in the settings where people with substance use disorders receive care.

Unsettling trend: The alarming rise of human abuse of veterinary drugs and its consequences

Veterinary practitioners often prescribe many controlled drugs to animals that may include sedatives, tranquilizers, and painkillers. Unfortunately, many of these drugs are drugs that can be abused by humans, especially among the pet owners. Adequate measures are required to prevent or detect the misuse of veterinary drugs. In this article, the phenomenon of the rising misuse of veterinary medications by humans and their potential health hazards which can accompany the unsettling trends in society has been highlighted. This article aims to shed light on the extent of issues, exploring reasons behind human abuse and its consequences.

Opioid-Associated Nervous System Injuries

With the rise of the opioid epidemic, the practicing neurologist must recognize the patterns of a growing number of opioid-associated neurological injuries. This is in addition to the classic toxidrome of miosis, altered mental status, and respiratory depression, which must never be overlooked, as it is reversible and potentially lifesaving. Several other idiosyncratic syndromes due to opioid-related nervous system insults are defined by their characteristic imaging findings and portend variable functional recovery. Opioid toxicity can not only lead to brain injury, but also spinal cord and, rarely, peripheral nerve injury. As several newer synthetic opioids are undetectable by most assays, a low threshold to suspect opioid exposure must be maintained.

Illicit Fentanyl Use and Hepatitis C Virus Seroconversion Among People Who Inject Drugs in Tijuana and San Diego: Results From a Binational Cohort Study

BACKGROUND

Illicitly manufactured fentanyl (IMF) increases overdose mortality, but its role in infectious disease transmission is unknown. We examined whether IMF use predicts hepatitis C virus (HCV) and human immunodeficiency virus (HIV) incidence among a cohort of people who inject drugs (PWID) in San Diego, California and Tijuana, Mexico.

METHODS

PWID were recruited during 2020-2022, undergoing semi-annual interviewer-administered surveys and HIV and HCV serological rapid tests through 2024. Cox regression was conducted to examine predictors of seroconversion considering self-reported IMF use as a 6-month lagged, time-dependent covariate.

RESULTS

Of 398 PWID at baseline, 67% resided in San Diego, 70% were male, median age was 43 years, 42% reported receptive needle sharing, and 25% reported using IMF. HCV incidence was 14.26 per 100 person-years (95% confidence interval [CI]: 11.49-17.02), and HIV incidence was 1.29 (95% CI: .49-2.10). IMF was associated with HCV seroconversion, with a univariable hazard ratio (HR) of 1.64 (95% CI: 1.09-2.40), and multivariable HR of 1.57 (95% CI: 1.03-2.40). The direction of the relationship with HIV was similar, albeit not significant (HR 2.39; 95% CI: .66-8.64).

CONCLUSIONS

We document a novel association between IMF and HCV seroconversion among PWID in Tijuana-San Diego. Few HIV seroconversions (n = 10) precluded our ability to assess if a similar relationship held for HIV. IMF's short half-life may destabilize PWID-increasing the need for repeat dosing and sharing smoking materials and syringes. New preventive care approaches may reduce HCV transmission in the fentanyl era.

Harm reduction nursing and the path toward developing best practice: Lessons from caring for people with xylazine-associated wounds in Philadelphia, PA

Xylazine-associated wounds are a distinct, novel clinical entity characterized by co-occurrence with substance use, progressive necrosis of skin, muscle, tendon, and bone, and slow healing. In Philadelphia, the specter of limb loss, stigma, and shame has hung over hospital-based care for xylazine-associated wounds among people who use drugs (PWUD) and kept many people away from engaging in care. Continued engagement in harm reduction wound care nursing, however, offers an opportunity for PWUD to address their wounds and their fears with members of the medical world. In the absence of established best practices, harm reduction's model of risk-reductive care offers a way forward for patients and practitioners alike. Here, "harm reduction" describes an ethic of practical, trauma-informed, patient-centered care. It is this integration of harm reduction into medicine and public health that effectively promotes the safety, survival, and recovery of PWUD across all spectrums of drug use habits and housing stability.

Identification of Catecholamine and Drug Target α2A-Adrenoceptor in Human Testis and Human Testicular Peritubular Cells

Background: Clonidine has been used in clinical medicine, e.g., to treat high blood pressure and other conditions. Animal studies have linked its use to impairments of male reproductive functions, and although only a few reports exist for the human species, such actions may exist in man as well. The underlying reasons and, specifically, possible actions of clonidine at the level of the testis are not known. Introduction: Clonidine is an agonist at the α2A-adrenoceptor (ADRA2A), which, as data bank mining indicated, is expressed by several cells of the human testis. The human testis and most of its cells are, however, not readily accessible to experimental testing. Cells from the peritubular wall compartment (human testicular peritubular cells; HTPCs) are the exception. Methods and Results: As shown by immunohistochemical/immunocytochemical and PCR techniques these cells express ADRA2A and retain expression upon isolation and culture. When tested over a concentration range (1-1000 µM) and 24 h, clonidine did not visibly affect HTPC morphology but significantly stimulated IL6 mRNA levels in a concentration-dependent manner. ELISA measurements of cell culture supernatants confirmed a stimulatory action of clonidine (10 µM) on secreted IL6. When examined in collagen gel contraction assays of HTPCs, clonidine (10 µM) exerted a slight relaxing action, while a proteomic study revealed that clonidine (10 µM) did not significantly change cellular protein abundance of HTPCs after 24 h (data available via ProteomeXchange with identifier PXD052220). Conclusion: Thus, ADRA2A-bearing cells in the human testis are targets for catecholamines and drugs such as clonidine. The results of this HTPCs-focused study only show the tip of the iceberg. It is likely that catecholamines/catecholaminergic drugs have the potential to interfere with human testicular functions.

Reported Xylazine Use Among Adults Aged ≥18 Years Evaluated for Substance Use Treatment - United States, July 2022-September 2023

Xylazine has been increasingly detected in illegally manufactured fentanyl (IMF) products and overdose deaths in the United States; most xylazine-involved overdose deaths involve IMF. A convenience sample of U.S. adults aged ≥18 years was identified from those evaluated for substance use treatment during July 2022-September 2023. Data were collected using the Addiction Severity Index-Multimedia Version clinical assessment tool. Among 43,947 adults, 6,415 (14.6%) reported IMF or heroin as their primary lifetime substance-use problem; 5,344 (12.2%) reported recent (i.e., past-30-day) IMF or heroin use. Among adults reporting IMF or heroin as their primary lifetime substance-use problem, 817 (12.7%) reported ever using xylazine. Among adults reporting recent IMF or heroin use, 443 (8.3%) reported recent xylazine use. Among adults reporting IMF or heroin use recently or as their primary lifetime substance-use problem, those reporting xylazine use reported a median of two past nonfatal overdoses from any drug compared with a median of one overdose among those who did not report xylazine use; as well, higher percentages of persons who reported xylazine use reported other recent substance use and polysubstance use. Provision of nonjudgmental care and services, including naloxone, wound care, and linkage to and retention of persons in effective substance use treatment, might reduce harms including overdose among persons reporting xylazine use.

"We only trust each other": A qualitative study exploring the overdose risk environment among persons who inject drugs living with HIV in Nairobi, Kenya

In Kenya, overdose remains a major public health concern with approximately 40% of persons who inject drugs (PWID) reporting personal overdoses. PWID living with HIV (PWID-LH) are particularly vulnerable to experiencing fatal and non-fatal overdoses because of the surrounding physical, social, economic, and political environments, which are not fully understood in Kenya. Through qualitative inquiry, this study characterizes Kenya's overdose risk environment. Participants were purposively recruited from a larger cohort study from September to December 2018 using the following inclusion criteria: HIV-positive, age ≥18 years, injected drugs in the last year, and completed cohort study visits. Semi-structured interviews explored experiences of personal and observed overdoses, including injection settings, sequence of events (e.g., pre-, during, and post-overdose), safety strategies, and treatment. Interviews were transcribed, translated (Swahili to English), reviewed, and analyzed thematically, applying a risk environment framework. Nearly all participants described personal and/or observed overdose experiences (96%) and heroin was the most frequently reported substance (79%). Overdose precursors included increased consumption, polysubstance use, recent incarceration, and rushed injections. There were also indications of female-specific precursors, including violence and accessing prefilled syringes within occupational settings. Overdose safety strategies included avoiding injecting alone, injecting drugs incrementally, assessing drug quality, and avoiding polysubstance use. Basic first-aid techniques and naloxone use were common treatment strategies; however, naloxone awareness was low (25%). Barriers to treatment included social network abandonment, police discrimination, medical stigma, fatalism/religiosity, medical and transportation costs, and limited access to treatment services. In Kenya, the overdose risk environment highlights the need for comprehensive overdose strategies that address the physical, social, economic, and political environments. Morbidity and mortality from overdose among PWID-LH could be reduced through overdose prevention initiatives that support harm reduction education, naloxone awareness, and access, destigmatization of PWID, and reforming punitive policies that criminalize PWID-LH.

Broad evidence of xylazine in the UK illicit drug market beyond heroin supplies: Triangulating from toxicology, drug-testing and law enforcement

BACKGROUND AND AIMS

Xylazine is a non-opioid sedative which has spread rapidly throughout the US illicit drug supply. This study aimed to describe the spread of xylazine throughout the UK illicit drug supply.

METHODS

Xylazine detections in human biological samples were collated from toxicology laboratories operating in the United Kingdom with the date, location, case type, xylazine concentration and co-detected drugs (with quantifications where performed) detailed, where permitted, by the corresponding coroner. Drug-testing cases positive for xylazine were collated from the Welsh Emerging Drugs and Identification of Novel Substances (WEDINOS) drug-testing postal service with the date, location, purchase intent and co-detected drugs detailed. Drug seizures made by UK law enforcement were communicated by the Office for Health Improvement and Disparities with the date and location detailed.

RESULTS

By the end of August 2023, xylazine was detected in 35 cases from throughout toxicology, drug-testing and drug seizure sources covering England, Scotland and Wales. There were no cases reported from Northern Ireland. Xylazine was detected in biological samples from 16 people. In most cases where full toxicology results were provided, xylazine was detected with heroin and/or a strong opioid (n = nine of 11), but this polydrug use pattern was not evident in all cases (n = two of 11), suggesting a wider circulation of xylazine in the UK illicit drug market beyond heroin supplies. Evidence from WEDINOS supports this claim, as all 14 drug samples (100%) submitted from across the UK contained xylazine; however, in none of these cases was heroin the purchase intent but rather counterfeit prescription medication tablets (n = 11 of 14), tetrahydrocannabinol (THC) vapes (n = two of 14) or white powder (n = one of 14). Additional evidence for the spread of illicit xylazine comes from five drug seizures made by law enforcement.

CONCLUSIONS

Xylazine has penetrated the UK illicit drug market and is not limited to heroin supplies.

National Institute on Drug Abuse Clinical Trials Network Meeting Report: Managing Patients Exposed to Xylazine-Adulterated Opioids in Emergency, Hospital and Addiction Care Settings

Used as a veterinary sedative and not approved for human use, xylazine has been increasingly linked with opioid overdose deaths in the United States. A growing number of people have been exposed to xylazine in the illicit opioid supply (especially fentanyl) or in other drugs, particularly in some areas of the Northeast. Xylazine is an α-2 adrenergic agonist that decreases sympathetic nervous system activity. When combined with fentanyl or heroin, it is purported to extend the duration of the opioid's sedative effect and to cause dependence and an associated withdrawal syndrome; however, data to support these concerns are limited. Despite the escalating frequency of detection of xylazine in people with nonfatal and fatal opioid overdose, direct links to these outcomes have not been identified. Because the strongest causal link is to fentanyl coexposure, ventilatory support and naloxone remain the cornerstones of overdose management. Xylazine is also associated with severe tissue injury, including skin ulcers and tissue loss, but little is known about the underlying mechanisms. Nonetheless, strategies for prevention and treatment are emerging. The significance and clinical effects of xylazine as an adulterant is focused on 4 domains that merit further evaluation: fentanyl-xylazine overdose, xylazine dependence and withdrawal, xylazine-associated dermal manifestations, and xylazine surveillance and detection in clinical and nonclinical settings. This report reflects the Proceedings of the National Institute on Drug Abuse Center for the Clinical Trials Network convening of clinical and scientific experts, federal staff, and other stakeholders to describe emerging best practices for treating people exposed to xylazine-adulterated opioids. Participants identified scientific gaps and opportunities for research to inform clinical practice in emergency departments, hospitals, and addiction medicine settings.

Water, sanitation and hygiene insecurity predict abscess incidence among people who inject drugs in a binational US-Mexico metropolitan area: A longitudinal cohort study

INTRODUCTION

People who inject drugs (PWID) are at high risk of developing injection-related infections, including abscesses. Access to water, sanitation, and hygiene (WASH) are key human rights and services; yet these services have been underexplored as predictors of abscesses among PWID.

METHODS

Longitudinal analysis was employed among a cohort of PWID to determine if WASH insecurity (lack of access) was associated with abscess incidence in the Tijuana, Mexico and San Diego, United States metropolitan area during 24-months of follow-up survey data from 2020 to 2023. We calculated abscess prevalence at baseline and tracked the incidence of new abscesses among individuals without an abscess during the previous visit. Time dependent Cox regression modeling was employed with variance clustered by participant to characterize the relationship between WASH insecurity and abscess incidence.

RESULTS

At baseline, hand hygiene insecurity, bathing insecurity in the previous six months and open defecation in the last week, were reported by 60 %, 54 % and 38 % of participants, respectively; 21 % reported an abscess in the last six months. The incidence of abscesses was 24.4 (95 %CI: 21.1-27.6) per 100 person-years. After adjusting for covariates, the hazard of developing an abscess remained significantly elevated among individuals using non-improved (with risk of contamination) water sources (e.g., surface water) for preparing drugs (adjusted HR [adjHR]: 1.49 [95 %CI: 1.01-2.21], experiencing bathing insecurity (adjHR: 1.59 [95 %CI: 1.12-2.24]) and open defecation (adjHR: 1.65 [95 %CI: 1.16-2.35]).

CONCLUSIONS

PWID in the Tijuana-San Diego metropolitan area reported facing high rates of insecurity accessing WASH services. Abscess incidence was higher (four to nine times) than observed rate among PWID cohorts in other settings. Access to continuously available toilet facilities, bathing infrastructure, and safe water sources for preparing drugs for injection could prevent abscesses among PWID. Accessible WASH infrastructure should be ensured among PWID communities and promoted as a key component of harm reduction infrastructure.

A content analysis of legal policy responses to xylazine in the illicit drug supply in the United States

BACKGROUND

Xylazine is a veterinary sedative that is quickly spreading in the U.S. illicit drug supply and is increasingly associated with fatal overdoses and severe wounds. In response, xylazine has been deemed an emerging public health threat and several policy initiatives have been introduced to combat its spread and negative broad health impact. We aimed to synthesize trends in all-time U.S. policy responses to xylazine in the drug supply.

METHODS

In April 2024, we systematically identified and categorized proposed and enacted policy initiatives that related to human xylazine consumption by searching LexisNexis and Thomas Reuters Westlaw legal databases.

RESULTS

Of 58 unique policy initiatives, most were introduced in 2023 (n = 37/58, 64 %) and concentrated in Northeastern states. Penalties for xylazine possession, often tied to state drug scheduling changes, were the most common provision (n = 34/58; 59 %) and Schedule III was the most frequently proposed scheduling level (n = 17/30; 57 %). Other provisions included proposals to enhance: test strip access (n = 11/58; 19 %), public awareness and education (n = 3/58; 5 %), xylazine-specific research (n = 4/58; 7 %), and surveillance (n = 8/58; 14 %).

CONCLUSION

U.S. state and federal policy responses to xylazine grew rapidly in 2023, were most concentrated in states affected most by xylazine, and scheduling was the most commonly proposed policy approach. Research measuring policy effects should be prioritized as policies are implemented.

Pilot findings on the real-world performance of xylazine test strips for drug residue testing and the importance of secondary testing methods

Background

Xylazine is a sedative found increasingly in the illicit fentanyl supply that can cause hypotension, bradycardia, necrosis and death. This pilot examined the real-world performance of BTNX xylazine test strips (XTS) in drug residue samples.

Methods

This study was nested within a drug checking service in Rhode Island. We tested unmeasured drug residue dissolved in 5 mL of distilled water using XTS and Liquid Chromatography Quadrupole Time-of-Flight Mass Spectrometry (LC-QTOF-MS). Analyses compared XTS and LC-QTOF-MS results to calculate XTS detection of xylazine in residue.

Results

Among 41 residue samples, xylazine was detected in 11% by the XTS and 44 % by the laboratory. The LC-QTOF-MS detected xylazine in 18 samples: 4 major, 9 minor, 5 trace by volume relative to the whole sample. The XTS disagreed with the LC-QTOF-MS by indicating a negative result in 77.8 % (N=14) of the samples but never indicated a positive when the LC-QTOF-MS reported xylazine's absence. The XTS correctly detected xylazine 22 % of the time, however, this increased to 100 % of the time if xylazine was a major active component.

Conclusions

In this study, the BTNX XTS often disagreed with LC-QTOF-MS by indicating a negative result, likely due to the dilution levels used and sample composition. The XTS may not be accurate in detecting residual amounts of xylazine, especially if xylazine is not a dominant component of the tested sample. Given the novelty of BTNX's XTS products, we recommend XTS only be used in conjunction with other advanced drug checking modalities for residue testing.

Combined treatment with naloxone and the alpha2 adrenoceptor antagonist atipamezole reversed brain hypoxia induced by a fentanyl-xylazine mixture in a rat model

Xylazine, a veterinary tranquillizer known by drug users as "Tranq", is being increasingly detected in people who overdose on opioid drugs, indicating enhanced health risk of fentanyl-xylazine mixtures. We recently found that xylazine potentiates fentanyl- and heroin-induced brain hypoxia and eliminates the rebound-like post-hypoxic oxygen increases. Here, we used oxygen sensors coupled with high-speed amperometry in rats of both sexes to explore the treatment potential of naloxone plus atipamezole, a selective α2-adrenoceptor antagonist, in reversing brain (nucleus accumbens) and periphery (subcutaneous space) hypoxia induced by a fentanyl-xylazine mixture. Pretreatment with naloxone (0.2 mg/kg, IV) fully blocked brain and peripheral hypoxia induced by fentanyl (20 μg/kg, IV), but only partially decreased hypoxia induced by a fentanyl-xylazine mixture. Pretreatment with atipamezole (0.25 mg/kg, IV) fully blocked the hypoxic effects of xylazine (1.0 mg/kg, IV), but not fentanyl. Pretreatment with atipamezole + naloxone was more potent than naloxone alone in blocking the hypoxic effects of the fentanyl-xylazine mixture. Both naloxone and naloxone + atipamezole, delivered at the peak of brain hypoxia (3 min post fentanyl-xylazine exposure), reversed the rapid initial brain hypoxia, but only naloxone + atipamezole decreased the prolonged weaker hypoxia. There were no sex differences in the effects of the different drugs and their combinations on brain and peripheral oxygen responses. Results indicate that combined treatment with naloxone and atipamezole is more effective than naloxone alone in reversing the hypoxic effects of fentanyl-xylazine mixtures. Naloxone + atipamezole treatment should be considered in preventing overdoses induced by fentanyl-xylazine mixtures in humans.

Trends in Fatal Opioid-Related Overdose in American Indian and Alaska Native Communities, 1999-2021

INTRODUCTION

Opioid-related overdose mortality rates have increased sharply in the U.S. over the past two decades, and inequities across racial and ethnic groups have been documented. Opioid-related overdose trends among American Indian and Alaska Natives require further quantification and assessment.

METHODS

Observational, U.S. population-based registry data on opioid-related overdose mortality between 1999 and 2021 were extracted in 2023 using ICD-10 codes from the U.S. Centers for Disease Control and Prevention's Wide-Ranging Online Data for Epidemiologic Research multiple cause of death file by race, Hispanic ethnicity, sex, and age. Segmented time series analyses were conducted to estimate opioid-related overdose mortality growth rates among the American Indian and Alaska Native population between 1999 and 2021. Analyses were performed in 2023.

RESULTS

Two distinct time segments revealed significantly different opioid-related overdose mortality growth rates within the overall American Indian and Alaska Native population, from 0.36 per 100,000 (95% CI=0.32, 0.41) between 1999 and 2019 to 6.5 (95% CI=5.7, 7.31) between 2019 and 2021, with the most pronounced increase among those aged 24-44 years. Similar patterns were observed within the American Indian and Alaska Native population with Hispanic ethnicity, but the estimated growth rates were generally steeper across most age groups than across the overall American Indian and Alaska Native population. Patterns of opioid-related overdose mortality growth rates were similar between American Indian and Alaska Native females and males between 2019 and 2021.

CONCLUSIONS

Sharp increases in opioid-related overdose mortality rates among American Indian and Alaska Native communities are evident by age and Hispanic ethnicity, highlighting the need for culturally sensitive fatal opioid-related overdose prevention, opioid use disorder treatment, and harm-reduction efforts. Future research should aim to understand the underlying factors contributing to these high mortality rates and employ interventions that leverage the strengths of American Indian and Alaska Native culture, including the strong sense of community.

Wastewater Surveillance for Xylazine in Kentucky

Introduction

In the U.S., xylazine, the veterinary non-opioid sedative, has emerged as a major threat to people who use illicitly manufactured fentanyl and other drugs. The aim of this study was to compare wastewater detection of xylazine with other public health and safety surveillance data from 2019 to 2023 in Kentucky.

Methods

Wastewater samples from 5 rest areas, 2 truck weigh stations, and 4 wastewater treatment plants were tested for xylazine. Wastewater xylazine positivity rates were compared with xylazine-positive submission rates from the National Forensic Laboratory Information System and Kentucky's fatal overdoses in 6-month periods (Period 1=January-June; Period 2=July-December).

Results

Xylazine was detected in 61.6% (424 of 688) of daily wastewater samples from roadway sites/wastewater treatment plants. For roadways, detection increased from 55% (Period 1, 2021) to 94% (Period 1, 2023), and wastewater treatment plants had an overall detection of 25.8% (n=66 samples, Periods 1 and 2, 2022). Increasing roadway positivity corresponded to trends in National Forensic Laboratory Information System xylazine-positive submission rates: from 0.19 per 1,000 submissions (Period 1, 2019) to 2.9 per 1,000 (Period 2, 2022, latest available). No deaths from xylazine were reported publicly in Kentucky, although this study's authors identified 1-4 deaths (true count suppressed) in the overdose surveillance system, which, in back-of-the-envelope comparisons with other states, is far fewer than expected.

Conclusions

Wastewater signals indicate broad geographic exposure to xylazine in Kentucky, yet health outcomes data suggest otherwise. These findings may inform regional, national, and international efforts to incorporate wastewater-based drug surveillance. Harm-reduction activities along roadways and other suitable locations may be needed.

High-dose naloxone formulations are not as essential as we thought

Naloxone is an effective FDA-approved opioid antagonist for reversing opioid overdoses. Naloxone is available to the public and can be administered through intramuscular (IM), intravenous (IV), and intranasal spray (IN) routes. Our literature review investigates the adequacy of two doses of standard IM or IN naloxone in reversing fentanyl overdoses compared to newer high-dose naloxone formulations. Moreover, our initiative incorporates the experiences of people who use drugs, enabling a more practical and contextually-grounded analysis. The evidence indicates that the vast majority of fentanyl overdoses can be successfully reversed using two standard IM or IN dosages. Exceptions include cases of carfentanil overdose, which necessitates ≥ 3 doses for reversal. Multiple studies documented the risk of precipitated withdrawal using ≥ 2 doses of naloxone, notably including the possibility of recurring overdose symptoms after resuscitation, contingent upon the half-life of the specific opioid involved. We recommend distributing multiple doses of standard IM or IN naloxone to bystanders and educating individuals on the adequacy of two doses in reversing fentanyl overdoses. Individuals should continue administration until the recipient is revived, ensuring appropriate intervals between each dose along with rescue breaths, and calling emergency medical services if the individual is unresponsive after two doses. We do not recommend high-dose naloxone formulations as a substitute for four doses of IM or IN naloxone due to the higher cost, risk of precipitated withdrawal, and limited evidence compared to standard doses. Future research must take into consideration lived and living experience, scientific evidence, conflicts of interest, and the bodily autonomy of people who use drugs.

Leveraging pooled medical examiner records to surveil complex and emerging patterns of polysubstance use in the United States

BACKGROUND

The United States (US) is an extreme global outlier for drug-related death rates. However, data describing drug-related deaths are generally available only on an 8-13-month lag. Furthermore, granular details about substance-involvement are often not available, which particularly stymies efforts to track fatal polysubstance and novel psychoactive substance use. Detailed medical examiner records provide a powerful source of information for drug-related death surveillance, but have been underutilized.

METHODS

We pooled medical examiner data from five US states and 14 counties that together comprise 18% of the US population to examine demographic, geographic, and drug-specific trends in polysubstance drug-related deaths. We employed mixed effects logistic regression to identify demographic factors associated with polysubstance rather than single substance drug-related deaths. We assessed the correlations between drug classes and described geographic variation in the prevalence of specific drugs and the presence of novel and emerging psychoactive substances.

RESULTS

Our sample included 73,077 drug-related deaths from 2012 through early 2022. Nearly two-thirds of drug-related deaths were polysubstance-involved, with the number and percentage growing annually. High percentages of polysubstance drug-related deaths were observed in both urban and rural jurisdictions. After adjusting for year and jurisdiction, female, American Indian and Alaska Native, and White individuals had the most elevated odds of polysubstance drug-related deaths. Drug-related deaths involving benzodiazepines or opioids, whether pharmaceutical or illicit, and other pharmaceutical drugs were most likely to have polysubstance involvement, while methamphetamine-involved deaths were least likely to involve multiple substances. Strong correlations were observed between prescription opioids and prescription benzodiazepines, fentanyl and xylazine, and designer benzodiazepines and novel synthetic opioids.

CONCLUSIONS

Analysis of detailed medical examiner records reveals the breadth and complexity of polysubstance drug-related deaths in the US. Future efforts to use this unique resource can improve population-based surveillance of drug-related deaths to better tailor interventions and solutions to this critical health crisis.

Missouri's Overdose Field Report: descriptive analysis, survival trends, and naloxone dosing patterns from a community-based survey tool, 2018-2022

Background: Missouri's Overdose Field Report (ODFR) is a community-based reporting system which intends to capture overdoses which may not be otherwise recorded.Objectives: Describe the factors related to non-fatal overdoses reported to Missouri's ODFR.Methods: This study used a descriptive epidemiological approach to examine the demographics and circumstances of overdoses reported to the ODFR. We used binary logistic regression to evaluate factors associated with survival and ordinal logistic regression to evaluate factors associated with number of doses used. Factors were chosen based on their relevance to overdose education and survival, and naloxone distribution.Results: Between 2018 and 2022, 12,225 overdoses (67% male; 78% White) were reported through the ODFR, with a 96% (n = 11,225) survival rate. Overdose survival (ps < .02) was associated with younger age (OR = .58), no opioid and stimulant co-involvement (OR = .61), and private location (OR = .48). Intramuscular naloxone in particular was associated with a significantly higher odds of survival compared to nasal naloxone (OR = 2.11). An average of 1.6 doses of naloxone per incident were administered. Additional doses were associated (ps < .02) with being older (OR = .45), female (OR = .90), nasal naloxone (versus intravenous) (OR = .65), and the belief fentanyl was present (OR = 1.49).Conclusion: Our reporting form provides a comprehensive picture of the events surrounding reported overdoses, including factors associated with survival, how much naloxone was used, and the effects of respondents believing fentanyl was involved. Missouri's report can provide support for current naloxone dosing, contextualize refusing post-overdose transport, and can be used to improve overdose response by community and first responders.

Xylazine does not enhance fentanyl reinforcement in rats: A behavioral economic analysis

The adulteration of illicit fentanyl with the alpha-2 agonist xylazine has been designated an emerging public health threat. The clinical rationale for combining fentanyl with xylazine is currently unclear, and the inability to study fentanyl/xylazine interactions in humans warrants the need for preclinical research. We studied fentanyl and xylazine pharmacodynamic and pharmacokinetic interactions in male and female rats using drug self-administration behavioral economic methods. Fentanyl, but not xylazine, functioned as a reinforcer under both fixed-ratio and progressive-ratio drug self-administration procedures. Xylazine combined with fentanyl at three fixed dose-proportion mixtures did not significantly alter fentanyl reinforcement as measured using behavioral economic analyses. Xylazine produced a proportion-dependent decrease in the behavioral economic Q0 endpoint compared to fentanyl alone. However, xylazine did not significantly alter fentanyl self-administration at FR1. Fentanyl and xylazine co-administration did not result in changes to pharmacokinetic endpoints. The present results demonstrate that xylazine does not enhance the addictive effects of fentanyl or alter fentanyl plasma concentrations. The premise for why illicitly manufacture fentanyl has been adulterated with xylazine remains to be determined.

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.

Xylazine: A Drug Adulterant of Clinical Concern

PURPOSE OF REVIEW

The opioid epidemic has been responsible for significant morbidity and mortality in the USA and worldwide. As a result, it is essential to recognize the threat these potent drugs can cause when illicitly used. Specifically, introducing fentanyl as a drug adulterant has been shown to impact overdose rates drastically. In this regard, the Drug Enforcement Agency recently released a public safety alert announcing the new threat of a new adulterant called xylazine. Xylazine is a powerful animal sedative with a different mechanism of action when compared to illicit opioids such as heroin and fentanyl. Xylazine is typically injected intravenously via a syringe, often in combination with multiple other drugs. One of the most common drugs, xylazine, is taken in combination with fentanyl, with users of this drug combination describing xylazine as prolonging the euphoric sensation produced by fentanyl.

RECENT FINDINGS

Xylazine may cause adverse effects such as bradycardia, brief hypertension followed by hypotension, premature ventricular contractions, ataxia, slurred speech, sedation, and respiratory depression. Much of the recent literature on xylazine use in humans comes from case reports and review articles. Related to widespread use in veterinary medicine and increasing circulation in illicit drug markets, there is a critical need for public awareness and additional clinical-based studies to further increase understanding of mediated or modulated pharmacological effects of xylazine in humans. Further research is urgently needed to more clearly understand the implications of unregulated xylazine in the illicit drug market, to formulate public health interventions, and to implement harm reduction strategies.

Necrotic Upper-Extremity Infections in People Who Inject Drugs: A Case Series

PURPOSE

Our institution has noted an increase in severe upper-extremity infections within the last 2 years. These patients have required transhumeral amputation. This case series demonstrates some of the catastrophic outcomes of these infections in people who inject drugs, which has been postulated to be related to the addition of xylazine to injectable drugs in our community.

METHODS

The study included patients presenting with severe upper-extremity infections resulting from intravenous drug use and requiring upper-extremity amputation between January 1, 2020 and September 30, 2022 at a single, urban, level 1 trauma center. Patient information and clinical images were collected through retrospective chart review.

RESULTS

Eight patients were identified at our institution with extensive necrosis of the skin and soft tissues in the forearm and hand, resulting in exposure of the radius and ulna. None of these patients had viable motor function in the hand and presented with a lack of sensation. All underwent transhumeral amputations, including bilaterally in one case.

CONCLUSIONS

The patients in this case series self-reported injection of tranquilizer-containing drugs, and xylazine has been reported to be present in 91% of heroin and fentanyl samples in our community. Although more studies are needed to confirm that xylazine is the definitive cause of the extensive tissue necrosis seen in these patients, we have found the severity of these infections to be noteworthy, given the likely expansion of xylazine to drug samples beyond our region.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

"It gets you high as a kite but not unsick": Characterizations of and responses to a changing local drug supply by people who use drugs in Rhode Island

BACKGROUND

The North American overdose crisis has continued at unprecedented rates with more than 100,000 overdose deaths occurring in the United States (US) in 2022. Overdose deaths have increasingly been polysubstance-involved, with novel substances (e.g., xylazine) complicating overdose risk and health outcomes. Understanding the effects of-and responses to-a changing drug supply among people who use drugs is critical to modifying harm reduction strategies to be more responsive to people's needs.

METHODS

This qualitative study draws on data collected from May to December 2022 in Rhode Island. Data include in-depth interviews with 50 people who use drugs and observational fieldwork in spaces frequented by participants (e.g., encampments, drop-in centers). Qualitative data were analyzed thematically drawing on concepts of situated rationality.

RESULTS

Participants described significant changes in the drug supply, with many attributing these transitions to COVID-19. Most participants characterized the local supply as "synthetic" with textures, color, and taste evolving. Notably, participants emphasized adverse outcomes related to available supplies, including during use (e.g., intense burning sensations) and post-consumption (e.g., heavy sedation, ongoing withdrawal, necrosis). Given the complex supply, participants highlighted the increased risk of overdose and shared how they altered their use practices to manage evolving health risks.

CONCLUSION

Our results underscore how people who use drugs characterized the local drug supply, including perceived changes to supply contents. Implementing and scaling up harm reduction interventions that reduce risk and reinforce the agency of people who use drugs are urgently needed to effectively address the overdose crisis.

Evaluation of a hapten conjugate vaccine against the "zombie drug" xylazine

Xylazine has emerged as a primary adulterant in fentanyl, exacerbating the complexity of the opioid crisis. Yet, there is no approved drug that can reverse xylazine's pathophysiology. As a prelude to monoclonal antibodies being assessed as a viable therapeutic, a vaccine inquiry was conducted evaluating the immune response in reversing xylazine induced behavior effects.

Collateral Damage: Neurological Correlates of Non-Fatal Overdose in the Era of Fentanyl-Xylazine

Non-fatal opioid overdoses are associated with significant morbidity. Hypoxic brain injury caused by opioid-induced respiratory depression is a key mechanism of such morbidity. For example, reports describe an amnestic syndrome in opioid users associated with acute injury to the hippocampus, a brain region that is highly susceptible to hypoxic injury. In our recent study we investigated the effects of non-fatal opioid overdose on the hippocampal volume in a well-characterized sample of opioid use disorder (OUD) patients with a history of overdose (OD) compared to those with no prior overdose (NOD). Using structural magnetic resonance imaging (MRI) and voxel-based morphometry, we observed lower hippocampal volume in patients with a history OD than in the NOD group. These findings support an association between non-fatal opioid overdose and hippocampal injury, which we hypothesize contributes to recently reported cases of OUD related amnestic syndrome. Here we review our study findings and the potential pathophysiological mechanisms underlying the acute and delayed hippocampal injury in nonfatal opioid overdose. We also discuss the implications for the risk of overdose and brain injury with the increased prevalence of fentanyl and xylazine contamination of the illicit opioid supply. Lastly, we highlight considerations for clinical management of the underappreciated neurological injury and cognitive dysfunction in OUD patients.

A quantitative LC-MS/MS analysis of Xylazine, p-Fluorofentanyl, Fentanyl and Fentanyl-Related compounds in postmortem blood

The purpose of this study was to develop and validate a method to quantitate the veterinary sedative xylazine as well as 4-anilino-N-phenethylpiperidine (4-ANPP), acetyl fentanyl, fentanyl, norfentanyl, and p-fluorofentanyl in blood utilizing liquid chromatography tandem mass spectrometry. This method also qualitatively monitors for the presence of o-fluorofentanyl and m-fluorofentanyl isomers. UCT Clean Screen® DAU extraction columns were utilized to isolate the analytes in postmortem blood samples. The extracts were eluted, evaporated, reconstituted, and then analyzed using a Waters Acquity™ UPLC coupled a triple quadrupole mass spectrometer. The lower limit of quantitation was determined to be 0.1 ng/mL for all analytes, except for xylazine (0.2 ng/mL). The upper limit of quantitation for all analytes was 100 ng/mL. No interferences from matrix, internal standard, or common drug analytes were observed. Bias (-13.1-4.6 %) and precision (-13.14-10.3 %) fell within the acceptable ± 20 % criteria range. Dilution integrity at x2, x10, and x100 was evaluated and all results were within ± 20 % of the target concentration. Processed extract stability was evaluated after 72 h and all results were within ± 20 % of the analyte initial concentration. Matrix effects were the most prominent with xylazine, but deemed acceptable as the deuterated internal standard also observed comparable enhancement. Analysis of 89 postmortem blood samples by this method resulted in positive results for fentanyl (0.27-66 ng/mL, n = 82), xylazine (0.24-958 ng/mL, n = 21), 4-ANPP (0.10-38 ng/mL, n = 72), acetyl fentanyl (0.18-1.5 ng/mL, n = 3), p-fluorofentanyl (0.11-33 ng/mL, n = 30), and norfentanyl (0.10-98 ng/mL, n = 73).

Volatile drug use and overdose during the first year of the COVID-19 pandemic in the United States

BACKGROUND

Overdose deaths in the United States rose substantially during the COVID-19 pandemic. Disruptions to the drug supply and service provision introduced significant instability into the lives of people who use drugs (PWUD), including volatility in their drug use behaviors.

METHODS

Using data from a multistate survey of PWUD, we examined sociodemographic and drug use correlates of volatile drug use during COVID-19 using multivariable linear regression. In a multivariable logistic regression model, we assessed the association between volatile drug use and past month overdose adjusting for sociodemographic and other drug use characteristics.

RESULTS

Among participants, 52% were male, 50% were white, 29% had less than a high school education, and 25% were experiencing homelessness. Indicators of volatile drug use were prevalent: 53% wanted to use more drugs; 45% used more drugs; 43% reported different triggers for drug use, and 23% used drugs that they did not typically use. 14% experienced a past-month overdose. In adjusted models, hunger (β=0.47, 95% CI: 0.21-0.72), transactional sex (β=0.50, 95% CI: 0.06-0.94), and the number of drugs used (β=0.16, 95% CI: 0.07-0.26) were associated with increased volatile drug use. Volatile drug use was associated with increased overdose risk (aOR=1.42, 95% CI: 1.17-1.71) in the adjusted model.

CONCLUSIONS

Volatile drug use during the COVID-19 pandemic was common, appeared to be driven by structural vulnerability, and was associated with increased overdose risk. Addressing volatile drug use through interventions that ensure structural stability for PWUD and a safer drug supply is essential for mitigating the ongoing overdose crisis.

Xylazine suppresses fentanyl consumption during self-administration and induces a unique sex-specific withdrawal syndrome that is not altered by naloxone in rats

Prescription and illicit opioid use are a public health crisis, with the landscape shifting to fentanyl use. Since fentanyl is 100-fold more potent than morphine, its use is associated with a higher risk of fatal overdose that can be remediated through naloxone (Narcan) administration. However, recent reports indicate that xylazine, an anesthetic, is increasingly detected in accidental fentanyl overdose deaths. Anecdotal reports suggest that xylazine may prolong the fentanyl "high," alter the onset of fentanyl withdrawal, and increase resistance to naloxone-induced reversal of overdose. To date, no preclinical studies have evaluated the impacts of xylazine on fentanyl self-administration (SA; 2.5 μg/kg/infusion) or withdrawal to our knowledge. We established a rat model of xylazine/fentanyl co-SA and withdrawal and evaluated outcomes as a function of biological sex. When administered alone, chronic xylazine (2.5 mg/kg, intraperitoneal) induced unique sex-specific withdrawal symptomatology, whereby females showed delayed onset of signs and a possible enhancement of sensitivity to the motor-suppressing effects of xylazine. Xylazine reduced fentanyl consumption in both male and female rats regardless of whether it was experimenter-administered or added to the intravenous fentanyl product (0.05, 0.10, and 0.5 mg/kg/infusion) when compared to fentanyl SA alone. Interestingly, this effect was dose-dependent when self-administered intravenously. Naloxone (0.1 mg/kg, subcutaneous injection) did not increase somatic signs of fentanyl withdrawal, regardless of the inclusion of xylazine in the fentanyl infusion in either sex; however, somatic signs of withdrawal were higher across time points in females after xylazine/fentanyl co-SA regardless of naloxone exposure as compared to females following fentanyl SA alone. Together, these results indicate that xylazine/fentanyl co-SA dose-dependently suppressed fentanyl intake in both sexes and induced a unique withdrawal syndrome in females that was not altered by acute naloxone treatment. (PsycInfo Database Record (c) 2024 APA, all rights reserved).