Notes from the Field: Xylazine, a Veterinary Tranquilizer, Identified as an Emerging Novel Substance in Drug Overdose Deaths - Connecticut, 2019-2020

Xylazine in the Unregulated Drug Market: An Integrative Review of Its Prevalence, Health Impacts, and Detection and Intervention Challenges in the United States

Xylazine, a veterinary sedative, has emerged as a concerning element in the landscape of substance use in the United States. This integrative review synthesizes evidence from a systematic examination of 14 selected studies conducted between 2008 and 2023. The primary objective is to comprehensively understand the epidemiology and prevalence of xylazine use, particularly its involvement in drug-related deaths, regional variations, national impact, co-occurrence with opioids, and challenges associated with detection and intervention. The results underscore stark regional disparities in xylazine prevalence. West Virginia and Miami-Dade County have experienced alarming surges in xylazine-involved drug-related deaths. Nationally, its influence extends beyond regional boundaries, predominantly affecting white males in the Northeast. The co-occurrence of xylazine with opioids, especially fentanyl and heroin, significantly amplifies the risks of fatal overdoses. Detecting xylazine presents formidable challenges due to its frequent presence alongside other substances, necessitating enhanced surveillance and more effective detection methods. User perspectives emerge as pivotal, emphasizing the importance of user-informed harm reduction strategies. In conclusion, this review has significant policy implications. Tailored, region-specific strategies are imperative to address the diverse prevalence of xylazine use. A nationwide response is indispensable, prioritizing harm reduction initiatives, enhanced detection methods, and active user engagement. The multifaceted nature of the xylazine issue requires comprehensive approaches to mitigate its profound risks effectively. Policymakers are urged to consider regional disparities and the co-occurrence of xylazine with opioids when crafting targeted interventions. Immediate, user-informed harm reduction is vital to address the evolving landscape of xylazine use in the United States.

Modeling Changes of Fatal Xylazine-Involved Drug Overdoses in Connecticut Across Time

BACKGROUND

Fatal drug overdoses have involved both xylazine and fentanyl. Xylazine is a non-opioid substance used in veterinary medicine. This study aimed to model changes in fatal xylazine-involved drug overdose deaths from 2019 to 2023 in Connecticut using overdose death data from the Office of the Chief Medical Examiner.

METHODS

Xylazine-involved drug overdose fatality rates were calculated by number of deaths per year per 100,000 population from 2019 to 2023. We used joinpoint regression modeling to evaluate quarterly overdose rates across age, number of drugs, and drug types with a significance level of p < 0.05.

RESULTS

From 2019 to 2023, there were 1116 xylazine-involved fatal overdoses with a cumulative rate of 31.3 deaths per 100,000. Xylazine-involved overdose death rates were significantly higher in Hispanic populations compared to both non-Hispanic White and Black populations (p < 0.05). The joinpoint analyses showed that xylazine-fentanyl mortality rates significantly increased by 0.18 per 100,000 per quarter from 2019 to 2022. Xylazine-fentanyl overdoses involving at least 4 or 5 substances significantly increased. Windham, Hartford, New London, and New Haven counties had the highest xylazine-involved death rates.

CONCLUSION

Xylazine-fentanyl deaths increased from 2019 to 2023, and often involved multiple substances (e.g., cocaine, ethanol, benzodiazepines, and oxycodone). Results show Hispanic populations, those aged 35-49, and 50+ experienced high rates of xylazine-fentanyl overdose deaths. Vulnerable populations in Connecticut for special consideration for future intervention and local resource allocation are recommended.

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.

Classics in Chemical Neuroscience: Xylazine

Xylazine (also known as "tranq") is a potent nonopioid veterinary sedative that has recently experienced a surge in use as a drug adulterant, most often combined with illicitly manufactured fentanyl. This combination may heighten the risk of fatal overdose. Xylazine has no known antidote approved for use in humans, and age-adjusted overdose deaths involving xylazine were 35 times higher in 2021 than 2018. In April 2023, the Biden Administration declared xylazine-laced fentanyl an emerging drug threat in the United States. In 2022, the Drug Enforcement Agency (DEA) reported nearly a quarter of seized fentanyl powder contained xylazine. This dramatic increase in prevalence has solidified the status of xylazine as an emerging drug of abuse and an evolving threat to public health. The following narrative review outlines the synthesis, pharmacokinetics, pharmacodynamics, and adverse effects of xylazine, as well as the role it may play in the ongoing opioid epidemic.

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.

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.

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.

A confirmed case of xylazine-induced skin ulcers in a person who injects drugs in Miami, Florida, USA

BACKGROUND

Xylazine is an alpha-2 adrenergic receptor agonist that has emerged as a contaminant in the illicit drug supply of fentanyl. Xylazine use may be suspected in naloxone-resistant overdoses and atypical, chronic wounds in people who use drugs (PWUD). This case is unique because it is the first case to our knowledge describing wound care for a xylazine-induced wound with a confirmatory xylazine test strip (XTS) in the setting of a syringe services program (SSP) and in the state of Florida.

CASE PRESENTATION

A 43-year-old woman with a past medical history of severe opioid use disorder and stimulant use disorder presented to a student-run clinic at a Miami SSP for wound care. She had multiple ulcerations diffusely over her bilateral forearms with surrounding erythema and warmth. Seven weeks later, she presented to clinic again for wound care because her wounds had progressed. At this visit, a XTS was used to confirm the presence of xylazine in her urine. Wound care management and harm reduction strategies employed at both visits were informed by best clinical judgement due to lack of formal guidelines at the time. Wound outcomes are unknown as the patient has not returned to clinic.

CONCLUSIONS

Many PWUD at highest risk for acute and chronic health consequences of xylazine-adulterated fentanyl do not have access to healthcare outside of low barrier clinics and SSPs due to lack of insurance or mistrust of the traditional healthcare system due to stigma. There is an urgent need for access to XTS for PWUD and clinical practice guidelines for the treatment of xylazine-related wounds in outpatient clinics.

Xylazine in Overdose Deaths and Forensic Drug Reports in US States, 2019-2022

Importance

Xylazine is increasingly reported in street drugs and fatal overdoses in the US, yet state-level data are limited, hampering local public health responses.

Objective

To gather available state-level data on xylazine involvement in overdose deaths and in forensic drug reports.

Design, Setting, and Participants

This cross-sectional study was a secondary analysis of 2019 to 2022 data from the National Forensic Laboratory Information System (NFLIS), National Center for Health Statistics, and individual states' medical examiner or public health agency reports. Data were analyzed from August to October 2023.

Exposure

State.

Main Outcomes and Measures

Yearly xylazine-related overdose deaths per 100 000 residents; xylazine NFLIS drug reports, both per 100 000 residents and as a percentage of all NFLIS drug reports (from samples of drugs seized by law enforcement and analyzed by NFLIS-participating laboratories).

Results

A total of 63 state-years were included in analyses of mortality rates, while 204 state-years were included in analyses of NFLIS reports. According to the publicly available data compiled in this study, at least 43 states reported at least 1 xylazine-related overdose death from 2019 to 2022, yet yearly totals of xylazine-related deaths were available for only 21 states. Of states with data available, xylazine-involved overdose death rates were highest in Vermont (10.5 per 100 000 residents) and Connecticut (9.8 per 100 000 residents) in 2022. In 2019, 16 states had zero xylazine reports included in NFLIS reports; in 2022, only 2 states had zero xylazine reports and all but 3 states had recorded an increase in xylazine's representation in NFLIS reports. In 2022, xylazine represented 16.17% of all NFLIS reports in Delaware and between 5.95% and 7.00% of NFLIS reports in Connecticut, Maryland, District of Columbia, New Jersey, and Rhode Island, yet less than 1.0% of NFLIS reports in 35 different states.

Conclusions and Relevance

In this cross-sectional study of publicly available data on fatal overdoses and drugs analyzed by forensic laboratories, xylazine's reported presence in overdose deaths and forensic reports was concentrated in the eastern US yet extended across the country to encompass nearly all states. In spite of xylazine's geographic reach, yearly state-level numbers of xylazine-related overdose deaths were publicly available for less than half of all states.

Evaluation of the relationship of xylazine and fentanyl blood concentrations among fentanyl-associated fatalities

INTRODUCTION

Illicit fentanyl and fentanyl-analogs have produced a devastating increase in opioid fatalities in the United States. Increasingly, xylazine has been found in the illicit fentanyl supply. The role of xylazine in fentanyl intoxication remains unclear. We reviewed coroner records to evaluate trends and effects associated with xylazine in fentanyl-related fatalities.

METHODS

This is a retrospective cohort study of all deaths reported to the Franklin County Coroner's Office in Ohio from 1 January 2019 to 16 March 2023, in which fentanyl was determined causative or contributory to death. Cases identified as fentanyl-associated fatalities were separated into two groups based on whether or not xylazine was also detected.

RESULTS

There were 3,052 fentanyl-related fatalities during the study period. 4.8 percent of these decedents also tested positive for xylazine. There was no meaningful demographic difference between fentanyl-related fatalities in which xylazine was detected versus those without xylazine detected. There was a mean of 726 fentanyl-associated fatalities per year, with a peak of 846 deaths in 2020 and a decline thereafter. The percentage of fentanyl-related fatalities with xylazine detected increased in linear fashion from 2.7 percent in 2019 to 6.6 percent in 2022. The median fentanyl concentration was 17.0 µg/L (inter-quartile range: 7.9, 27.0) in cases with xylazine detected and 10.0 µg/L (inter-quartile range: 5.6, 18.0) without xylazine. The odds of a fentanyl concentration greater than 40 µg/L in cases with xylazine detected was more than twice as great (odds ratio: 2.41; 95 percent confidence interval: 1.58-3.64) than that in cases without xylazine detected.

CONCLUSIONS

Postmortem fentanyl concentrations were greater in cases with xylazine detected than those without xylazine detected. Though it is unclear why patients who were exposed to xylazine tolerated higher opioid doses prior to succumbing to death, we postulate that xylazine may act to competitively antagonize some degree of mu-opioid receptor binding by opioids.

Xylazine Poisoning in Clinical and Forensic Practice: Analysis Method, Characteristics, Mechanism and Future Challenges

Xylazine abuse is emerging globally, while the identification of xylazine lethal cases poses a great challenge in clinical and forensic practice. The non-specific symptoms delay the diagnosis and treatment of xylazine poisoning, the pathological changes and lethal concentration of xylazine in body fluid and organs of fatal xylazine poisoning cases are seldom reported and the other toxins detected in such cases complicate the role of xylazine in the cause of death. Therefore, we carefully reviewed related updated information on xylazine, summarized the knowledge from clinical and forensic perspectives and can thus provide a reference in such cases and throw light on further study in the field of xylazine poisoning.

Recognition and Treatment of Wounds in Persons Using Xylazine: A Case Report From New Haven, Connecticut

BACKGROUND

Xylazine is an α 2 -adrenergic agonist that is commonly used as a veterinary tranquilizer and is increasingly present in the unregulated US drug supply since at least 2019. There are many suspected clinical complications of xylazine use, including unusual skin wounds, atypical overdose presentations, and possible dependence and withdrawal syndromes. However, there are few reports of cutaneous manifestations of xylazine in patients who inject drugs that can guide diagnosis and management in patients with confirmed xylazine toxicology.

CASE SUMMARY

We present the cases of 3 stably housed patients in Connecticut with opioid use disorder and intravenous use of fentanyl who presented with atypical, chronic wounds at the site of injection drug use. Xylazine toxicology sent on all 3 patients was positive. All patients were seen by wound care and dermatology, and 1 patient was followed by infectious diseases. Wound care management strategies are discussed as well as harm reduction strategies. For all patients, the dose of their medication for opioid use disorder was increased to decrease frequency of drug use given concern that patients were exposed to a drug supply containing xylazine.

CLINICAL SIGNIFICANCE

This case report presents wound characteristics that raise the index of suspicion for xylazine-involved injection wounds and might assist in their diagnosis and management. There is urgent need for more reporting of such cases as well as rigorous research to understand the potential impact of xylazine on people who use drugs. Multidisciplinary best practices should be established.

Xylazine in the drug supply: Emerging threats and lessons learned in areas with high levels of adulteration

BACKGROUND

Xylazine, a sedative analgesic drug approved as an animal tranquilizer but not for human use, has become an adulterant in the illicit opioid marketplace in North America. Recently declared an emerging health threat in the U.S., the prevalence of xylazine in overdose deaths increased 5.5-fold between 2019 and 2021. More information is needed about the impact of xylazine on opioid users and harm reduction service providers.

METHODS

The impact of xylazine adulteration was triangulated through examination of (1) opioid overdose fatalities in Connecticut between 2017 and 2021 reported by the Office of the Chief Medical Examiner data, (2) a convenience survey of people in Connecticut who use drugs (PWUD) regarding their knowledge of and attitude about the local illicit drug supply, and (3) semi-structured interviews of harm reduction service providers in Connecticut and Philadelphia in response to prompts on the impacts of and responses to xylazine adulteration.

RESULTS

The presence of fentanyl or its analogues in fatal opioid overdoses was a statistically significant predictor of xylazine presence [OR = 25.0, 95%CI (10.7,81.1)] as was being Hispanic [OR = 1.36, 95%CI (1.03,1.77)]. A survey of people who used drugs revealed that 43% (n = 286) were concerned that the drug supply was always unpredictable. Three-quarters of respondents were aware of xylazine and two-thirds would use a xylazine test strip if one was available. Respondents who identified as White, Hispanic were most likely to be aware of xylazine, to have used a fentanyl test strip, and to be interested in a xylazine test strip. Respondents who injected drugs were 3.6-fold more likely than those who did not inject to endorse an interest in a xylazine test strip. Harm reduction service providers were cognizant of a range of problems surrounding the use and injection of xylazine. Although they reported implementing practices to better respond to xylazine harms, they recognized the absence of solutions to many of the problems encountered.

CONCLUSION

The prevalence of xylazine has expanded, especially in combination with fentanyl. Harm reduction education efforts with fidelity to best practices have emerged, but the harms persist and community prevention needs are largely unmet.

Public health impact and harm reduction implications of xylazine-involved overdoses: a narrative review

INTRODUCTION

Xylazine, an α2-adrenoceptor agonist sedative commonly used in veterinary medicine, is not approved for human use. Nevertheless, xylazine-involved overdose rates have surged in recent years, fueled by an increasingly toxic and synthetic illicit drug supply in North America.

METHODS

This narrative review assessed major epidemiological trends in xylazine-involved overdoses in North America, aiming to identify harm reduction priorities. A literature search was conducted using four bibliographic databases (PubMed, Scopus, Embase, and ScienceDirect) and three preprint servers (medRxiv, bioRxiv, and Europe PMC) on May 28, 2023, to capture articles related to combinations of keywords such as "xylazine", "opioid", and "harm reduction".

RESULTS

Xylazine emerged as an adulterant in Puerto Rico in 2001, likely diverted from veterinary supplies. By the mid-2010s, it began proliferating across unregulated US drug markets, often contemporaneously with illicitly manufactured fentanyl (IMF), displaying characteristics of a syndemic. Initially concentrated in Northeastern regions (e.g., Philadelphia, Connecticut, Maryland), xylazine-involved overdoses later extended to the Rust Belt, Southern, and Western regions of the USA in the late 2010s and early 2020s. During this time, xylazine-involved overdoses also surged in Canada, particularly in Western provinces (British Columbia and Alberta) and Ontario with established IMF-dominated unregulated drug markets.

DISCUSSION

Over the past two decades, xylazine-involved overdoses have been rapidly rising in North America and exhibit few signs of slowing down, representing a serious public health epidemic. Numerous factors may have contributed to this, including limited epidemiological surveillance and drug checking for xylazine and emerging novel adulterants; further, barriers to comprehensive, trauma-informed, non-stigmatizing treatment and social services have also exacerbated this issue. While several epidemiological and ethnographic studies have assessed these factors in the USA, limited evidence is available in Canada where xylazine emerged more recently. This underscores the need for additional research and harm reduction measures.

CONCLUSION

Harm reduction-informed public health guidelines and programs are urgently needed to promote a safer supply, strengthen the healthcare system capacity to prevent and respond to xylazine-involved overdoses, and address social and structural disparities in health outcomes.

Xylazine in Drug Seizure Reports and Overdose Deaths in the US, 2018-2022

Xylazine is increasingly reported in street drugs and fatal overdoses in the United States (US), often in combination with synthetic opioids, yet state-level xylazine data are limited, hampering local public health responses. The present study analyzed 2018-2022 state-level data from the National Forensic Laboratory Information System (xylazine-positive reports of seized drugs analyzed by forensic laboratories), the Centers for Disease Control and Prevention (population estimates, synthetic opioid overdose mortality rates), and individual states' medical examiner/public health agency reports (numbers of xylazine-involved overdose deaths). An ordinary least squares regression model predicted state-level synthetic opioid overdose mortality rates by xylazine seizure report rates, adjusting for US Census Region. In 2018, relatively low rates of xylazine seizure reports were observed, with 21 states reporting zero xylazine seizures. In 2022, only three states reported zero xylazine seizures, and the highest xylazine seizure report rates (per 100,000 residents) were observed in New Jersey (30.4), Rhode Island (22.7), Maryland (18.9), Virginia (15.5), New Hampshire (13.0), and Ohio (10.9). Data on 2019-2022 xylazine-involved overdose deaths were available for 21 states/DC (60 state-years), with the highest 2022 xylazine-involved overdose death rates (per 100,000 residents) in Vermont (10.5) and Connecticut (9.8). Finally, in 2021, at the state level, each additional reported xylazine seizure per 100,000 residents was associated with a 2% higher synthetic opioid overdose mortality rate (b=0.02, robust standard error=0.01; p=0.049). Overall, study results emphasize xylazine's increasing involvement in US law enforcement drug seizure reports and overdose deaths, primarily in the East, yet also extending across the country.

A Confirmed Case of Xylazine-Induced Skin Ulcers in a Person Who Injects Drugs in Miami, Florida, USA

Background

Xylazine is an alpha-2 adrenergic receptor agonist that has emerged as a contaminant in the street drug supply of fentanyl. Xylazine use may be suspected in naloxone-resistant overdoses and atypical, chronic wounds in people who inject drugs (PWID). This case is unique because it is the first case to our knowledge describing wound care for a xylazine-induced wound with a confirmatory xylazine test strip (XTS) in the setting of a syringe services program (SSP) and in the state of Florida.

Case Presentation

A 43-year-old woman with a past medical history of severe opioid use disorder and stimulant use disorder presented to a student-run clinic at the IDEA Miami SSP for wound care. She had multiple ulcerations diffusely over her bilateral forearms with surrounding erythema and warmth. Seven weeks later, she presented to clinic again for wound care because her wounds had progressed. At this visit, a XTS was used to confirm the presence of xylazine in her urine. Wound care management and harm reduction strategies employed at both visits are discussed below. Wound outcomes are unknown as the patient has not returned to clinic.

Conclusions

Many PWID at highest risk for acute and chronic health consequences of xylazine-adulterated fentanyl do not have access to healthcare outside of low barrier clinics and SSPs due to lack of insurance or mistrust of the traditional healthcare system. There is an urgent need for access to XTS for PWID and clinical practice guidelines for the treatment of xylazine-related wounds in outpatient clinics.

Xylazine-involved fatal overdoses and localized geographic clustering: Cook County, IL, 2019-2022

BACKGROUND

Xylazine, a veterinary analgesic sedative, is circulating in the illicit drug markets of at least 23 states including Illinois. We conducted a geographic analysis to better identify the spatial distribution of xylazine-involved fatal overdoses in Cook County, IL.

METHODS

Cook County Medical Examiner Office's (CCMEO) publicly available data was used to identify xylazine-involved fatal overdoses from January 1, 2019, to June 30, 2022. Xylazine-positive (cases) to xylazine-negative groups with drug mixtures involving fentanyl, alcohol and stimulants (controls) were matched on age, race, sex, and year of death. Ripley's K-function was used to examine the likelihood of case clustering compared to controls with the Bernoulli spatial scan deployed to identify specific geographic clusters.

RESULTS

Almost all (94.4%) xylazine-positive overdoses contained fentanyl. Using coordinate-based matching, we found that approximately 3% of xylazine overdose incidents were co-located with other overdoses. Xylazine cases clustered to from 0 to 16.1 miles (max=10.6 miles). Results of the Bernoulli spatial scan varied by control group with two high-risk clusters found relative to alcohol and stimulants and a low-risk cluster relative to fentanyl. Differences in co-occurring drugs were found between xylazine and fentanyl groups like the absolute number of drugs (4.6v 3.4, p<0.0001) and fentanyl analog types.

CONCLUSIONS

Xylazine fatal overdose incident locations exhibited localized clustering relative to fentanyl overdoses but clusters were not precisely detected at these scales. Even so, our results, especially relative to repeat overdose micro "hot spots", offer insight on targeting harm reduction and other services at the neighborhood-level.

The New Stealth Drug on the Street: A Narrative Review of Xylazine as a Street Drug

Xylazine is an alpha-adrenergic receptor agonist approved for use only in animals with a prescription from a veterinarian. It is a powerful sedative that is slowly infiltrating the recreational street drug scene and is often used by polysubstance abusers. Known as "tranq," it can be fatal, and xylazine-induced toxicity cannot be reversed with naloxone or nalmefene. Due to its vasoconstrictive effects, chronic use of xylazine is associated with necrotic skin lesions and general deterioration of health. Since xylazine is not approved for human use and is not scheduled as a controlled substance, there are no human studies to provide evidence of drug-drug interactions, lethal doses, or reversal protocols. Xylazine is available online without a prescription. Street drug users may take xylazine knowingly or unknowingly, as it is often combined with other illicit substances such as fentanyl. There are no rapid tests for xylazine, although there are specialty tests that can be ordered. Xylazine represents a major threat to street drug users and another challenge to emergency healthcare workers, first responders, and others who care for those who have taken this "new" street drug.

Characteristics of xylazine-related deaths in West Virginia-Xylazine-related deaths

BACKGROUND AND OBJECTIVES

The involvement of xylazine, a veterinary drug, in West Virginia (WV) human drug-related deaths was examined.

METHODS

WV drug deaths from 2019 (when xylazine was first identified) to mid-2021. Characteristics including toxicology findings were compared between xylazine and nonxylazine deaths.

RESULTS

Of 3292 drug deaths, 117 involved xylazine, and the proportions of deaths with it have increased (1% [2019] to 5% [mid-2021)]. Xylazine decedents had more cointoxicants, with fentanyl (98%) predominant followed by methamphetamine. Xylazine decedents had a significantly greater history of drug or alcohol misuse and hepatic disease.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

In one of the largest analyses of xylazine-involved deaths in a predominantly rural state, identification of xylazine was increasing with multiple cointoxicants (especially fentanyl), and was present in a few deaths with only one other substance involved. Health professionals should be aware of possible enhanced toxicity from xylazine ingestion especially since naloxone does not reverse xylazine's adverse effects.

Opioid overdoses involving xylazine in emergency department patients: a multicenter study

INTRODUCTION

Illicit opioids, consisting largely of fentanyl, novel synthetic opioids, and adulterants, are the primary cause of drug overdose fatality in the United States. Xylazine, an alpha-2 adrenergic agonist and veterinary tranquilizer, is being increasingly detected among decedents following illicit opioid overdose. Clinical outcomes in non-fatal overdose involving xylazine are unexplored. Therefore, among emergency department patients with illicit opioid overdose, we evaluated clinical outcome differences for patients with and without xylazine exposures.

METHODS

This multicenter, prospective cohort study enrolled adult patients with opioid overdose who presented to one of nine United States emergency departments between 21 September 2020, and 17 August 2021. Patients with opioid overdose were screened and included if they tested positive for an illicit opioid (heroin, fentanyl, fentanyl analog, or novel synthetic opioid) or xylazine. Patient serum was analyzed via liquid chromatography quadrupole time-of-flight mass spectroscopy to detect current illicit opioids, novel synthetic opioids, xylazine and adulterants. Overdose severity surrogate outcomes were: (a) cardiac arrest requiring cardiopulmonary resuscitation (primary); and (b) coma within 4 h of arrival (secondary).

RESULTS

Three hundred and twenty-one patients met inclusion criteria: 90 tested positive for xylazine and 231 were negative. The primary outcome occurred in 37 patients, and the secondary outcome occurred in 111 patients. Using multivariable regression analysis, patients positive for xylazine had significantly lower adjusted odds of cardiac arrest (adjusted OR 0.30, 95% CI 0.10-0.92) and coma (adjusted OR 0.52, 95% CI 0.29-0.94).

CONCLUSIONS

In this large multicenter cohort, cardiac arrest and coma in emergency department patients with illicit opioid overdose were significantly less severe in those testing positive for xylazine.

Rising abuse of veterinary drugs

ABSTRACT

There has been a significant increase in veterinary drugs found on toxicology screens and postmortem analyses, especially in the Northeast region of the US. This article details the effects and treatment of two common culprits: xylazine and tiletamine-zolazepam.

Xylazine and Overdoses: Trends, Concerns, and Recommendations

Xylazine is a nonopioid veterinary anesthetic and sedative that is increasingly detected in the illicit drug supply in the United States. Data indicate a striking prevalence of xylazine among opioid-involved overdose deaths. The emergence of xylazine in the illicit drug supply poses many unknowns and potential risks for people who use drugs. The public health system needs to respond by increasing testing to determine the prevalence of xylazine, identifying its potential toxicity at various exposure levels, and taking mitigating action to prevent harms. Currently, there is little testing capable of identifying xylazine in drug supplies, which limits the possibility of public health intervention, implementation of harm reduction strategies, or development of novel treatment strategies. (Am J Public Health. 2022;112(8):1212-1216. https://doi.org/10.2105/AJPH.2022.306881).

Perspectives of people in Philadelphia who use fentanyl/heroin adulterated with the animal tranquilizer xylazine; Making a case for xylazine test strips

Background

Xylazine is an animal tranquilizer increasingly detected in those who have died of an opioid overdose in Philadelphia, PA and elsewhere. Despite an increasing presence of xylazine in the local fentanyl/heroin drug market and its association with ulcers, there are few perspectives about xylazine from people who use drugs and no data about the utility of a hypothetical xylazine test strip.

Methods

Between January to May 2021 in Philadelphia, PA, people who used fentanyl/heroin and had previously used fentanyl test strips were queried about xylazine and hypothetical xylazine test strips. Interviews were transcribed and analysis was conducted via conventional content analysis.

Results

Participants (7 spontaneously, 6 after probing, n = 13) discussed "tranq" (i.e., xylazine) in the fentanyl/heroin supply. None enjoyed tranq or wanted it in their fentanyl/heroin. Participants suspected xylazine saturation of the fentanyl/heroin market, disliked the sensation of the drug, and had safety concerns about xylazine exposure. Participants did not indicate concerns about overdose. All were interested in hypothetical xylazine test strips. While previous literature indicates that some people enjoy tranq in their fentanyl/heroin, our findings differed, with participants expressing concern about the consequences of undesired exposure. The interest expressed for xylazine test strips by people who use fentanyl/heroin is an important opportunity to center their voices in the development of innovations designed to mitigate the harms of unwanted adulterant exposure.

Conclusions

In the present study, people who use fentanyl/heroin indicated an interest to test their drug for the presence of xylazine prior to use.

Xylazine poisoning: a systematic review

PURPOSE

Xylazine is an alpha-2-adrenergic agonist used for its sedative and analgesic properties in veterinary medicine. While not approved by the Food and Drug Administration for use in humans, anecdotal evidence suggests that exposures in humans is on the rise. We sought to systematically review and synthesize the evidence on xylazine exposure in humans focusing on the clinical presentation, management, and outcomes.

METHODS

We conducted a systematic review of the literature including PubMed, Embase, and Scopus from their inception to September 9, 2021. We searched abstracts from selected emergency medicine and toxicology conferences from 2011 through 2021. We included clinical reports of xylazine exposure in humans. We excluded animal studies, in vitro studies, laboratory studies, or articles in a language other than English. From each included article, we extracted subjective and objective data that focused on clinical presentation, management, and outcomes of patients exposed to xylazine.

RESULTS

We evaluated a total of 1409 records, rendering a final set of 17 articles and 2 abstracts meeting inclusion criteria. We identified a total of 98 patients amongst reports ranging from 1979 to 2020 and across nine countries. The most common types of xylazine exposures reported were unintentional exposure and intentional misuse/abuse. Common symptoms on presentation included hypotension, bradycardia, drowsiness, lethargy, while apnea with intubation and death were less frequently reported.

CONCLUSION

Human exposure to xylazine appears to be a rising concern within the prehospital and emergency medicine setting. Although a standardized treatment algorithm cannot be recommended at this time, further research is needed to improve the care of patients exposed to xylazine.