Use of Xylazine in Drug-Facilitated Crimes

Qualitative and quantitative determination of xylazine in oral fluid

Xylazine has emerged in recent years as a dangerous adulterant in illicit fentanyl use, and methods for the detection of xylazine in toxicology panels are still lagging. We developed methods for the screening and quantitation of xylazine in oral fluid (OF), a popular testing medium due to its ease of collection and reflection of presence in blood for many classes of drugs. Enzyme-linked immunosorbent assays were employed for the rapid screening of xylazine directly from the collection device buffer with a cutoff of 1 ng/mL. Solid-phase extraction coupled with liquid chromatography-tandem mass spectrometry facilitated the confirmation and quantification of xylazine as low as 0.1 ng/mL and a dynamic range of 0.1-25 ng/mL. Selectivity, ionization suppression, processed sample stability, and dilution effect were also assessed. The method was validated through the American National Standards Institute/American Academy of Forensic Sciences Standards Board (ANSI/ASB) Standard 036, first edition from 2019, and found to be accurate, precise, and robust. Living human subject OF samples collected within substance use disorder and therapeutic drug monitoring clinics received between September 2023 and January 2024, with the specific request to test for xylazine (n = 57), were screened. Presumptive positive samples were confirmed using the validated method. Xylazine confirmed living human subject OF sample concentrations ranged from 1.2 to 23.3 ng/mL.

Xylazine-Associated Wounds and Related Health Concerns Among People Who Use Drugs: Reports From Front-Line Health Workers in 7 US States

BACKGROUND

Xylazine, an adrenergic alpha-2 agonist increasingly present in the US drug supply, is associated with severe skin ulcers and other harms. Expert knowledge from front-line harm reduction and healthcare professionals is an essential component of evidence-based practice. The purpose of this study is to describe the progression and treatment of xylazine-associated wounds, other xylazine-related health concerns, and the most urgent research priorities as reported by front-line harm reduction and healthcare professionals serving people who use drugs.

METHODS

A convenience sample of 17 healthcare and harm reduction professionals who serve people who use drugs in the US states of Maryland, Massachusetts, Michigan, Minnesota, North Carolina, Pennsylvania, and Texas participated in semi-structured interviews. Participants were asked about the appearance and progression of xylazine-associated wounds; preferred treatment strategies; other xylazine-related harms experienced by people who use drugs; and the most urgent priorities for xylazine-related research.

FINDINGS

Xylazine-associated wounds were broadly described as small lesions appearing mostly on extremities both at and away from injection sites, often within hours or days of exposure, that quickly developed into large, complex, chronic wounds. Reported risk of secondary infection was generally low but appeared more common among unhoused populations. Most participants preferred conservative treatment strategies that included regular wound care, enzymatic debridement, and hygiene. Xylazine-associated wounds and xylazine withdrawal reportedly act as significant barriers to care, including addiction treatment. Participants reported urgent need for scientific research and evidence-based guidance on the management of xylazine-associated wounds and withdrawal.

CONCLUSIONS

High-quality scientific evidence on risk factors for xylazine-associated wounds and on their biologic mechanisms is needed. Such studies could inform new strategies for the prevention and treatment of these wounds. Efforts to improve the management of xylazine withdrawal and to reduce stigma by incorporating harm reduction professionals into healthcare settings may improve access to and retention in care.

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.

Xylazine in the Opioid Epidemic: A Systematic Review of Case Reports and Clinical Implications

INTRODUCTION AND OBJECTIVES

The opioid overdose epidemic is exacerbated by the emergence of Xylazine as an illicit drug adulterant. Xylazine, a veterinary sedative, can potentiate opioid effects while also causing toxic and potentially fatal side effects. This systematic review aims to assess the impact of Xylazine use and overdoses within the opioid epidemic context.

METHOD

A systematic search was conducted following PRISMA guidelines to identify relevant case reports, and case series related to Xylazine use. A comprehensive literature search included databases like Web of Science, PubMed, Embase, and Google Scholar, utilizing keywords and Medical Subject Headings (MeSH) terms related to Xylazine. Thirty-four articles met the inclusion criteria for this review.

RESULTS

Intravenous (IV) administration was a common route for Xylazine use among various methods, including subcutaneous (SC), intramuscular (IM), and inhalation, with overall doses ranging from 40 mg to 4300 mg. The average dose in fatal cases was 1,200 mg, compared to 525 mg in non-fatal cases. Concurrent administration of other drugs, primarily opioids, occurred in 28 cases (47.5%). Intoxication was identified as a notable concern in 32 out of 34 studies, and treatments varied, with the majority experiencing positive outcomes. Withdrawal symptoms were documented in one case study, but the low number of cases with withdrawal symptoms may be attributed to factors such as a limited number of cases or individual variation. Naloxone was administered in eight cases (13.6%), and all patients recovered, although it should not be misconstrued as an antidote for Xylazine intoxication. Of the 59 cases, 21 (35.6%) resulted in fatal outcomes, with 17 involving Xylazine use in conjunction with other drugs. The IV route was a common factor in six out of the 21 fatal cases (28.6%).

CONCLUSION

This review highlights the clinical challenges associated with Xylazine use and its co-administration with other substances, particularly opioids. Intoxication was identified as a major concern, and treatments varied across the studies, including supportive care, naloxone, and other medications. Further research is needed to explore the epidemiology and clinical implications of Xylazine use. Understanding the motivations and circumstances leading to Xylazine use, as well as its effects on users, is essential for developing effective psychosocial support and treatment interventions to address this public health crisis.

Self-reported Xylazine Experiences: A Mixed Methods Study of Reddit Subscribers

Objectives

Xylazine is an alpha-2 agonist increasingly prevalent in the illicit drug supply. Our objectives were to curate information about xylazine through social media from People Who Use Drugs (PWUDs). Specifically, we sought to answer the following: 1) what are the demographics of Reddit subscribers reporting exposure to xylazine? 2) is xylazine a desired additive? and 3) what adverse effects of xylazine are PWUDs experiencing?

Methods

Natural Language Processing (NLP) was used to identify mentions of "xylazine" from posts by Reddit subscribers who also posted on drug-related subreddits. Posts were qualitatively evaluated for xylazine-related themes. A survey was developed to gather additional information about the Reddit subscribers. This survey was posted on subreddits that were identified by NLP to contain xylazine-related discussions from March 2022 to October 2022.

Results

76 posts mentioning xylazine were extracted via NLP from 765,616 posts by 16,131 Reddit subscribers (January 2018 to August 2021). People on Reddit described xylazine as an unwanted adulterant in their opioid supply. 61 participants completed the survey. Of those that disclosed their location, 25/50 (50%) participants reported locations in the Northeastern United States. The most common eoute of xylazine use was intranasal use (57%). 31/59 (53%) reported experiencing xylazine withdrawal. Frequent adverse events reported were prolonged sedation (81%) and increased skin wounds (43%).

Conclusions

Among respondents on these Reddit forums, xylazine appears to be an unwanted adulterant. PWUDs may be experiencing adverse effects such as prolonged sedation and xylazine withdrawal. This appeared to be more common in the Northeast.

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.

An ultrasensitive monoclonal antibody-based lateral flow immunoassay for the rapid detection of xylazine in milk

In this study, a novel hapten was designed and successfully synthesized to prepared the artificial immunogen against xylazine (XYL), then the monoclonal antibody 1H2-2C6 was obtained and applied to a lateral flow immunoassay (LFI) strip for rapid detection of XYL in milk. The visual detection limit (cutoff value) of the LFI strip was 5 ng/mL, the linear regression formula was Y = -0.521lg(X) + 0.382 (R² = 0.995, n = 6), the linear detection range was 0.16-2.23 ng/mL and the detection limit (LOD) was 0.1 ng/mL. The recovery rates were in the range from 88.95% to 91.45%, the highest coefficient of variation was 8.89% (n = 3). The LFI strip was also validated by LC-MS/MS, as revealed, there were no significance differences between the two methods (the confidence interval was 95%). In brief, the LFI strip provides a reliable, sensitive and portable testing tool for screening of XYL on-site.

Xylazine: Pharmacology Review and Prevalence and Drug Combinations in Forensic Toxicology Casework

Xylazine, an alpha-2 receptor agonist used in veterinary medicine for its sedative and muscle relaxant effects, has been reported in forensic toxicology casework since the 1980s. It is not approved for human use, but it is used as an adulterant in heroin and illicit fentanyl. The prevalence and concentrations of xylazine in 2.5 years (January 2019-June 2021) of driving-under-the-influence-of-drugs (DUID) and medical-death-investigation (MDI) cases was investigated, including other drugs detected in combination with xylazine. Of over 170,000 cases screened for xylazine, 97% were classified as MDI. Over the course of the study period the prevalence and geographical spread of xylazine increased. Overall, 2.8% of DUID and 2.1% of MDI cases screened positive for xylazine with concentrations of 5.1-450 ng/mL (mean = 36 ng/mL) and 5.0-11,000 ng/mL (mean = 41 ng/mL), respectively. Two MDI cases which had xylazine concentrations of 9,100 and 11,000 ng/mL were drug overdose suicides that did not involve any opioids. Opioids, primarily fentanyl and/or a fentanyl byproduct/metabolite were detected in 100% of DUID and all but two MDI cases. After opioids, stimulants, phyto-cannabinoids and benzodiazepines were the most common drug classes detected in conjunction with xylazine in both DUID and MDI casework. In summary, xylazine exposure continues to increase, mostthrough the adulteration of illicit opioids. There is extensive overlap in the concentrations between living and deceased individuals making it difficult to interpret the role of the drug in MDI or DUID cases without other case information.

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.

Vortex-assisted dispersive liquid-liquid microextraction-gas chromatography (VADLLME-GC) determination of residual ketamine, nimetazepam, and xylazine from drug-spiked beverages appearing in liquid, droplet, and dry forms

Presently, investigations of drug-facilitated crimes (DFCs) rely on the detection of substances extracted from biological samples following intake by the victim. However, such detection requires rapid sampling and analysis prior to metabolism and elimination of the drugs from the body. In cases of suspected DFCs, drug-spiked beverage samples, whether in liquid, droplet, or even dried form, can be tested for the presence of spike drugs and used as evidence for the occurrence of DFCs. This study aimed to quantitatively determine three sedative-hypnotics (ketamine, nimetazepam, and xylazine) from drug-spiked beverages using a vortex-assisted dispersive liquid-liquid microextraction-gas chromatography (VADLLME-GC) approach. In this study, a GC method was first developed and validated, followed by the optimization of the VADLLME protocol, which was then applied to quantify the target substances in simulated forensic case scenarios. The developed GC method was selective, sensitive (limit of detection: 0.08 μg/ml [ketamine]; 0.16 μg/ml [nimetazepam]; 0.08 μg/ml [xylazine]), linear (R²  > 0.99), precise (%RSD <7.2%), and accurate (% recovery: 92.8%-103.5%). Higher recoveries were achieved for the three drugs from beverage samples in liquid form (51%-97%) as compared to droplet (48%-96%) and dried (44%-93%) residues. The recovery was not hindered by very low volumes of spiked beverage and dried residues. In conclusion, the developed VADLLME-GC method successfully recovered ketamine, nimetazepam, and xylazine from spiked beverages that are likely to be encountered during forensic investigation of DFCs.

Nanocoral-like Polyaniline-Modified Graphene-Based Electrochemical Paper-Based Analytical Device for a Portable Electrochemical Sensor for Xylazine Detection

A portable electrochemical device for xylazine detection is presented for the first time. An electrochemical paper-based analytical device (ePAD) was integrated with a smartphone. The fabrication of the ePAD involved wax printing, low-tack transfer tape, and cutting and screen-printing techniques. Graphene ink was coated on the substrate and modified with nanocoral-like polyaniline, providing an electron transfer medium with a larger effective surface area that promoted charge transfer. The conductive ink on the ePAD presented a thickness of 25.0 ± 0.9 μm for an effective surface area of 0.374 cm². This sensor was then tested directly on xylazine using differential pulse voltammetry. Two linear responses were obtained: from 0.2 to 5 μg mL^-1 and from 5 to 100 μg mL^-1. The detection limit was 0.06 μg mL^-1. Reproducibility was tested on 10 preparations. The relative standard deviation was less than 5%. The applicability of the sensor was evaluated with beverage samples spiked with trace xylazine. Recoveries ranged from 84 ± 4 to 105 ± 2%. The developed sensor demonstrated excellent accuracy in the detection of trace xylazine. It would be possible to develop the portable system to detect various illicit drugs to aid forensic investigations.

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.

Drug-facilitated sexual assault and other crimes: A systematic review by countries

Drug-facilitated sexual assault (DFSA) and drug-facilitated crime (DFC) constitute a mode of violence that is generally unknown to the population and may go unnoticed by health professionals. The aim of this systematic review was to analyze the victims of DFC, compiling their sociodemographic characteristics, the toxic substances used and their biological matrices and modes of action, in order to identify the substances that are commonly put to criminal use. The aim would be to establish political and health strategies that inform and warn people about possible criminal social behaviors consequent danger to health. This systematic review was conducted following the PRISMA guidelines. Alcohol, benzodiazepines and cocaine were among the most commonly detected substances. In most of the hospitals, immunoassays, liquid chromatography (LC-MS), or gas chromatography-mass spectrometry (GC-MS) analyses were used to identify the substances, while the most frequently used biological matrices were blood and urine. From a judicial point of view, the instrumental protocols and techniques followed for the detection of toxics in different biological matrices must guarantee the reliability and validity of the results for use in a court of law. The recommendations of international organizations should be followed and must be called upon to strengthen their respective national laws against this chemical submission (CS) phenomenon.

Interpol review of toxicology 2016-2019

This review paper covers the forensic-relevant literature in toxicology from 2016 to 2019 as a part of the 19th Interpol International Forensic Science Managers Symposium. The review papers are also available at the Interpol website at: https://www.interpol.int/content/download/14458/file/Interpol%20Review%20.Papers%202019.pdf.