Notes From the Field: Xylazine-Related Deaths — Cook County, Illinois, 2017–2021
Weekly / April 1, 2022 / 71(13);503–504
Please note: This report has been corrected. An erratum has been published.
Neeraj Chhabra, MD1,2; Mojde Mir, MPH3; Miao Jenny Hua, MD, PhD4,5; Sarah Berg, MD2; Juleigh Nowinski-Konchak, MD4,5,6; Steve Aks, DO1,2; Ponni Arunkumar, MD3; Keiki Hinami, MD6 (View author affiliations)
View suggested citationXylazine, an alpha-2 receptor agonist, is used in veterinary medicine as a sedative and muscle relaxant; it is not approved for use in humans. However, reports of adulteration of illicit opioids with xylazine have been increasing in the United States (1–3). In humans, xylazine can cause respiratory depression, bradycardia, and hypotension (4). Typical doses of naloxone are not expected to reverse the effects of xylazine; therefore, persons who use xylazine-adulterated opioids are at high-risk for fatal overdose. Although some regions of the United States have reported increases in xylazine-involved deaths, xylazine was involved in <2% of overdose deaths nationally in 2019 (2,5). Most xylazine-involved deaths are associated with fentanyls, including fentanyl analogs (1,5). Cook County, Illinois, is the second largest county in the United States and has a high incidence of opioid-related deaths involving fentanyl (6). To determine temporal trends in xylazine-involved deaths in Cook County, the Cook County Medical Examiner’s Office and Cook County Health analyzed suspected substance-related deaths from January 2017 to October 2021 for the presence of xylazine and co-occurring substances.
A xylazine-associated death was defined as a positive postmortem xylazine serum toxicology test result in an unintentional, undetermined, or pending intent substance-related death during January 2017–October 2021. Routine postmortem tests were conducted for other substances including fentanyl, fentanyl analogs, cocaine, and naloxone. Xylazine testing is standard in Cook County for suspected drug overdose deaths. This activity was reviewed by CDC and was conducted consistent with applicable federal law and CDC policy.*
A total of start highlight210end highlight xylazine-associated deaths were reported during the study period. Xylazine-associated deaths increased throughout the study period; incidence peaked during start highlightOctoberend highlight 2021 (Figure). The percentage of fentanyl-associated deaths involving xylazine also increased throughout the study period, rising to a peak of start highlight12.2%end highlight of fentanyl-related deaths assessed by the Cook County Medical Examiner’s Office during October 2021. Fentanyl or fentanyl analogs were detected on forensic testing in most xylazine-involved deaths (start highlight99.1%end highlight). Other common co-occurring substances included diphenhydramine (start highlight78.1%end highlight), cocaine (start highlight41.9%end highlight), and quinine (start highlight33.8%end highlight). Naloxone was detected in start highlight33.3%end highlight of xylazine-associated deaths.
These findings highlight a concerning trend in xylazine-involved deaths in Cook County, Illinois. Increased monitoring and public education within Cook County are warranted along with expanded surveillance in other jurisdictions, particularly those in which fentanyl use is highly prevalent. These findings can be helpful in guiding overdose prevention and response efforts because naloxone has not been shown to reverse the effects of xylazine. Although a specific antidote is not available for xylazine, naloxone should still be administered in suspected cases of potentially fatal overdose because most cases co-occur with opioids. Cardiovascular and respiratory support are critical to the management of serious xylazine toxicity; health care providers should be made aware that cases of suspected fentanyl overdose that are refractory to naloxone administration might involve xylazine toxicity. Designation of xylazine as a controlled substance has occurred in some states and would be an important policy to be considered more broadly.† In addition, expanded postmortem testing for xylazine and co-occurring substances across jurisdictions could better define the role of xylazine in opioid-related deaths.
Corresponding author: Neeraj Chhabra, Nchhabra@cookcountyhhs.org, 312-864-0065.
1Division of Medical Toxicology, Department of Emergency Medicine, Cook County Health, Chicago, Illinois; 2Toxikon Consortium, Chicago, Illinois; 3Cook County Medical Examiner’s Office, Chicago, Illinois; 4Department of Preventive Medicine, Cook County Health, Chicago, Illinois; 5Feinberg School of Medicine, Northwestern University, Chicago Illinois; 6Center for Health Equity and Innovation, Cook County Health, Chicago, Illinois.
All authors have completed and submitted the International Committee of Medical Journal Editors form for disclosure of potential conflicts of interest. Neeraj Chhabra reports grant support from the Institute for Intergovernmental Research, Bureau of Justice Assistance, U.S. Department of Justice. Keiki Hinami reports grant support from the Bureau of Justice Assistance, U.S. Department of Justice. Juleigh Nowinski-Konchak reports salary support from the U.S. Department of Justice; grant or contract support from the U.S. Department of Justice, Northwestern University, and the Health Resources and Service Administration; travel or meeting support from the Illinois Department of Human Services, Centers for Medicare & Medicaid, U.S. Department of Health and Human Services, and the U.S. Department of Justice; and participation on a data safety monitoring board and advisory board at Project STAMINA, Lighthouse Institute, Chestnut Health Systems. No other potential conflicts of interest were disclosed.
* 45 C.F.R. part 46.102(l)(2), 21 C.F.R. part 56; 42 U.S.C. Sect. 241(d); 5 U.S.C. Sect. 552a; 44 U.S.C. Sect. 3501 et seq.
References
- Johnson J, Pizzicato L, Johnson C, Viner K. Increasing presence of xylazine in heroin and/or fentanyl deaths, Philadelphia, Pennsylvania, 2010–2019. Inj Prev 2021;27:395–8. https://doi.org/10.1136/injuryprev-2020-043968external icon PMID:33536231external icon
- Thangada S, Clinton HA, Ali S, et al. Notes from the field: xylazine, a veterinary tranquilizer, identified as an emerging novel substance in drug overdose deaths—Connecticut, 2019–2020. MMWR Morb Mortal Wkly Rep 2021;70:1303–4. https://doi.org/10.15585/mmwr.mm7037a5external icon PMID:34529638external icon
- Nunez J, DeJoseph ME, Gill JR. Xylazine, a veterinary tranquilizer, detected in 42 accidental fentanyl intoxication deaths. Am J Forensic Med Pathol 2021;42:9–11. https://doi.org/10.1097/PAF.0000000000000622external icon PMID:33031124external icon
- Korn WR, Stone MD, Haviland KL, Toohey JM, Stickle DF. High prevalence of xylazine among fentanyl screen-positive urines from hospitalized patients, Philadelphia, 2021. Clin Chim Acta 2021;521:151–4. https://doi.org/10.1016/j.cca.2021.07.010external icon PMID:34265257external icon
- Kariisa M, Patel P, Smith H, Bitting J. Notes from the field: xylazine detection and involvement in drug overdose deaths—United States, 2019. MMWR Morb Mortal Wkly Rep 2021;70:1300–2. https://doi.org/10.15585/mmwr.mm7037a4external icon PMID:34529640external icon
- Nesoff ED, Branas CC, Martins SS. The geographic distribution of fentanyl-involved overdose deaths in Cook County, Illinois. Am J Public Health 2020;110:98–105. https://doi.org/10.2105/AJPH.2019.305368external icon PMID:31725315external icon
start highlightFIGURE. Number of xylazine-involved deaths (A) and percentage of fentanyl-involved deaths with detectable xylazine (B), by month — Cook County, Illinois, 2017–2021end highlight
Suggested citation for this article: Chhabra N, Mir M, Hua MJ, et al. Notes From the Field: Xylazine-Related Deaths — Cook County, Illinois, 2017–2021. MMWR Morb Mortal Wkly Rep 2022;71:503–504. DOI: http://dx.doi.org/10.15585/mmwr.mm7113a3external icon.
MMWR and Morbidity and Mortality Weekly Report are service marks of the U.S. Department of Health and Human Services.
Use of trade names and commercial sources is for identification only and does not imply endorsement by the U.S. Department of
Health and Human Services.
References to non-CDC sites on the Internet are
provided as a service to MMWR readers and do not constitute or imply
endorsement of these organizations or their programs by CDC or the U.S.
Department of Health and Human Services. CDC is not responsible for the content
of pages found at these sites. URL addresses listed in MMWR were current as of
the date of publication.
All HTML versions of MMWR articles are generated from final proofs through an automated process. This conversion might result in character translation or format errors in the HTML version. Users are referred to the electronic PDF version (https://www.cdc.gov/mmwr) and/or the original MMWR paper copy for printable versions of official text, figures, and tables.
Questions or messages regarding errors in formatting should be addressed to mmwrq@cdc.gov.