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Shaykin JD, Denehy ED, Martin JR, Chandler CM, Luo D, Taylor CE, Sunshine MD, Turner JR, Alilain WJ, Prisinzano TE, Bardo MT. Targeting α 1- and α 2-adrenergic receptors as a countermeasure for fentanyl-induced locomotor and ventilatory depression. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2024; 110:104527. [PMID: 39106924 PMCID: PMC11423298 DOI: 10.1016/j.etap.2024.104527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2024] [Revised: 07/12/2024] [Accepted: 08/02/2024] [Indexed: 08/09/2024]
Abstract
This study assessed the ability of α1 and α2-adrenergic drugs to decrease fentanyl-induced locomotor and ventilatory depression. Rats were given saline or fentanyl, followed by: (1) naltrexone, (2) naloxone, (3) nalmefene, (4) α1 agonist phenylephrine, (5) α1 antagonist prazosin, (6) α1D antagonist BMY-7378, (7) α2 agonist clonidine, (8) α2 antagonist yohimbine or (9) vehicle. All µ-opioid antagonists dose-dependently reversed fentanyl-induced locomotor and ventilatory depression. While the α1 drugs did not alter the effects of fentanyl, clonidine dose-dependently decreased locomotion and respiration with and without fentanyl. Conversely, yohimbine given at a low dose (0.3-1 mg/kg) stimulated ventilation when given alone and higher doses (>1 mg/kg) partially reversed (∼50 %) fentanyl-induced ventilatory depression, but not locomotor depression. High doses of yohimbine in combination with a suboptimal dose of naltrexone reversed fentanyl-induced ventilatory depression, suggestive of additivity. Yohimbine may serve as an effective adjunctive countermeasure agent combined with naltrexone to rescue fentanyl-induced ventilatory depression.
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Affiliation(s)
- Jakob D Shaykin
- Department of Psychology, University of Kentucky, Lexington, KY, USA
| | - Emily D Denehy
- Department of Psychology, University of Kentucky, Lexington, KY, USA
| | - Jocelyn R Martin
- Department of Psychology, University of Kentucky, Lexington, KY, USA
| | - Cassie M Chandler
- Department of Psychology, University of Kentucky, Lexington, KY, USA
| | - Dan Luo
- College of Pharmacy, University of Kentucky, Lexington, KY, USA
| | - Chase E Taylor
- Spinal Cord and Brain Injury Research Center (SCoBIRC) and Department of Neuroscience, University of Kentucky, Lexington, KY, USA
| | - Michael D Sunshine
- Spinal Cord and Brain Injury Research Center (SCoBIRC) and Department of Neuroscience, University of Kentucky, Lexington, KY, USA
| | - Jill R Turner
- College of Pharmacy, University of Kentucky, Lexington, KY, USA
| | - Warren J Alilain
- Spinal Cord and Brain Injury Research Center (SCoBIRC) and Department of Neuroscience, University of Kentucky, Lexington, KY, USA
| | | | - Michael T Bardo
- Department of Psychology, University of Kentucky, Lexington, KY, USA.
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2
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Demery-Poulos C, Moore SC, Levitt ES, Anand JP, Traynor JR. Xylazine Exacerbates Fentanyl-Induced Respiratory Depression and Bradycardia. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.08.16.608310. [PMID: 39229079 PMCID: PMC11370410 DOI: 10.1101/2024.08.16.608310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Fatal opioid overdoses in the United States have nearly tripled during the past decade, with greater than 92% involving a synthetic opioid like fentanyl. Fentanyl potently activates the μ-opioid receptor to induce both analgesia and respiratory depression. The danger of illicit fentanyl has recently been exacerbated by adulteration with xylazine, an α2-adrenergic receptor agonist typically used as a veterinary anesthetic. In 2023, over a 1,000% increase in xylazine-positive overdoses was reported in some regions of the U.S. Xylazine has been shown to potentiate the lethality of fentanyl in mice, yet a mechanistic underpinning for this effect has not been defined. Herein, we evaluate fentanyl, xylazine, and their combination in whole-body plethysmography (to measure respiration) and pulse oximetry (to measure blood oxygen saturation and heart rate) in male and female CD-1 mice. We show that xylazine decreases breathing rate more than fentanyl by increasing the expiration time. In contrast, fentanyl primarily reduces breathing by inhibiting inspiration, and xylazine exacerbates these effects. Fentanyl but not xylazine decreased blood oxygen saturation, and when combined, xylazine did not change the maximum level of fentanyl-induced hypoxia. Xylazine also reduced heart rate more than fentanyl. Finally, loss in blood oxygen saturation correlated with the frequency of fentanyl-induced apneas, but not breathing rate. Together, these findings provide insight into how the addition of xylazine to illicit fentanyl may increase the risk of overdose.
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Affiliation(s)
- Catherine Demery-Poulos
- Edward F. Domino Research Center, Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Sierra C Moore
- Edward F. Domino Research Center, Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Erica S Levitt
- Edward F. Domino Research Center, Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States
- Department of Anesthesiology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Jessica P Anand
- Edward F. Domino Research Center, Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States
| | - John R Traynor
- Edward F. Domino Research Center, Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI, United States
- Department of Medicinal Chemistry, University of Michigan College of Pharmacy, Ann Arbor, MI, United States
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3
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Hill K, Minahan-Rowley R, Biegacki ET, Heimer R, Sue KL. Providers' knowledge and perception of xylazine in the unregulated drug supply: a sequential explanatory mixed-methods study. Harm Reduct J 2024; 21:148. [PMID: 39148036 PMCID: PMC11328386 DOI: 10.1186/s12954-024-01052-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Accepted: 06/30/2024] [Indexed: 08/17/2024] Open
Abstract
BACKGROUND Xylazine is increasingly prevalent in the unregulated opioid supply in the United States. Exposure to this adulterant can lead to significant harm, including prolonged sedation and necrotic wounds. In the absence of literature describing healthcare providers' experiences with treating patients who have been exposed to xylazine, we aimed to explore what gaps must be addressed to improve healthcare education and best practices. METHODS From October 2023 to February 2024, we conducted a sequential explanatory mixed-methods study, with (1) a quantitative survey phase utilizing convenience sampling of healthcare providers treating patients in Connecticut and (2) a qualitative semi-structured interview phase utilizing purposive sampling of providers with experience treating patients with xylazine exposure. Summary statistics from the survey were tabulated; interview transcripts were analyzed using thematic analysis. RESULTS Seventy-eight eligible healthcare providers participated in our survey. Most participants had heard of xylazine (n = 69, 95.8%) and had some knowledge about this adulterant; however, fewer reported seeing one or more patients exposed to xylazine (n = 46, 59.8%). After sampling from this subgroup, we conducted fifteen in-depth interviews. This qualitative phase revealed five themes: (1) while xylazine is novel and of concern, this is not necessarily exceptional (i.e., there are other emerging issues for patients who use drugs); (2) participants perceived that xylazine was increasingly prevalent in the drug supply, even if they were not necessarily seeing more patients with xylazine-related outcomes (XROs); (3) patients primarily presented with non-XROs, making it difficult to know when conversations about xylazine were appropriate; (4) patients with XROs may experience issues accessing healthcare; (5) providers and their patients are learning together about how to minimize XROs and reduce the sense of helplessness in the face of a novel adulterant. CONCLUSIONS Xylazine-specific education for healthcare providers is currently insufficient. Improving this education, as well as resources (e.g., drug checking technologies) and data (e.g., research on prevention and treatment of XROs), is crucial to improve care for patients who use drugs.
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Affiliation(s)
- Katherine Hill
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA.
| | - Rebecca Minahan-Rowley
- Yale Program in Addiction Medicine, Yale School of Medicine, New Haven, CT, USA
- Department of General Internal Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Emma T Biegacki
- Yale Program in Addiction Medicine, Yale School of Medicine, New Haven, CT, USA
- Department of General Internal Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Robert Heimer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Kimberly L Sue
- Yale Program in Addiction Medicine, Yale School of Medicine, New Haven, CT, USA
- Department of General Internal Medicine, Yale School of Medicine, New Haven, CT, USA
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4
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Choi S, Noya MR, Kiyatkin EA. Oxygen fluctuations in the brain and periphery induced by intravenous fentanyl: effects of dose and drug experience. J Neurophysiol 2024; 132:322-334. [PMID: 38863429 PMCID: PMC11427041 DOI: 10.1152/jn.00177.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Revised: 05/24/2024] [Accepted: 06/05/2024] [Indexed: 06/13/2024] Open
Abstract
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.
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Affiliation(s)
- Shinbe Choi
- Behavioral Neuroscience BranchNational Institute on Drug Abuse-Intramural Research Program, National Insitutes of Health, Department of Health and Human Services, Baltimore, Maryland, United States
| | - Michael R Noya
- Behavioral Neuroscience BranchNational Institute on Drug Abuse-Intramural Research Program, National Insitutes of Health, Department of Health and Human Services, Baltimore, Maryland, United States
| | - Eugene A Kiyatkin
- Behavioral Neuroscience BranchNational Institute on Drug Abuse-Intramural Research Program, National Insitutes of Health, Department of Health and Human Services, Baltimore, Maryland, United States
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5
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Hoffman GR, Giduturi C, Cordaro NJ, Yoshida CT, Schoffstall AM, Stabio ME, Zuckerman MD. Classics in Chemical Neuroscience: Xylazine. ACS Chem Neurosci 2024; 15:2091-2098. [PMID: 38747710 DOI: 10.1021/acschemneuro.4c00172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2024] Open
Abstract
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.
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Affiliation(s)
- Gavin R Hoffman
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado 80045, United States
- Department of Chemistry and Biochemistry, University of Colorado Colorado Springs, Colorado Springs, Colorado 80918, United States
| | - Chetan Giduturi
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado 80045, United States
| | - Nicholas J Cordaro
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado 80045, United States
| | - Cassidy T Yoshida
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado 80045, United States
| | - Allen M Schoffstall
- Department of Chemistry and Biochemistry, University of Colorado Colorado Springs, Colorado Springs, Colorado 80918, United States
| | - Maureen E Stabio
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado 80045, United States
| | - Matthew D Zuckerman
- Department of Emergency Medicine, University of Colorado School of Medicine, Aurora, Colorado 80045, United States
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6
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Choi S, Irwin MR, Noya MR, Shaham Y, Kiyatkin EA. Combined treatment with naloxone and the alpha2 adrenoceptor antagonist atipamezole reversed brain hypoxia induced by a fentanyl-xylazine mixture in a rat model. Neuropsychopharmacology 2024; 49:1104-1112. [PMID: 38123817 PMCID: PMC11109156 DOI: 10.1038/s41386-023-01782-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 11/03/2023] [Accepted: 11/28/2023] [Indexed: 12/23/2023]
Abstract
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.
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Affiliation(s)
- Shinbe Choi
- Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, DHHS, Baltimore, MD, 21224, USA
| | - Matthew R Irwin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, DHHS, Baltimore, MD, 21224, USA
| | - Michael R Noya
- Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, DHHS, Baltimore, MD, 21224, USA
| | - Yavin Shaham
- Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, DHHS, Baltimore, MD, 21224, USA
| | - Eugene A Kiyatkin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, DHHS, Baltimore, MD, 21224, USA.
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7
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St Onge CM, Canfield JR, Ortiz A, Sprague JE, Banks ML. Xylazine does not enhance fentanyl reinforcement in rats: A behavioral economic analysis. Drug Alcohol Depend 2024; 258:111282. [PMID: 38593731 PMCID: PMC11146009 DOI: 10.1016/j.drugalcdep.2024.111282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Revised: 03/29/2024] [Accepted: 03/30/2024] [Indexed: 04/11/2024]
Abstract
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.
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Affiliation(s)
- Celsey M St Onge
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA 23298, USA; Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Jeremy R Canfield
- The Ohio Attorney General's Center for the Future of Forensic Sciences, Bowling Green State University, Bowling Green, OH, USA
| | - Allison Ortiz
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Jon E Sprague
- The Ohio Attorney General's Center for the Future of Forensic Sciences, Bowling Green State University, Bowling Green, OH, USA.
| | - Matthew L Banks
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298, USA.
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8
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Lin M, Eubanks LM, Zhou B, Janda KD. Evaluation of a hapten conjugate vaccine against the "zombie drug" xylazine. Chem Commun (Camb) 2024; 60:4711-4714. [PMID: 38596865 DOI: 10.1039/d4cc00883a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
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.
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Affiliation(s)
- Mingliang Lin
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute for Research and Medicine (WIRM), The Scripps Research Institute, La Jolla, CA, USA.
| | - Lisa M Eubanks
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute for Research and Medicine (WIRM), The Scripps Research Institute, La Jolla, CA, USA.
| | - Bin Zhou
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute for Research and Medicine (WIRM), The Scripps Research Institute, La Jolla, CA, USA.
| | - Kim D Janda
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute for Research and Medicine (WIRM), The Scripps Research Institute, La Jolla, CA, USA.
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9
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Todaro DR, Volkow ND, Langleben DD, Shi Z, Wiers CE. Collateral Damage: Neurological Correlates of Non-Fatal Overdose in the Era of Fentanyl-Xylazine. Neurosci Insights 2024; 19:26331055241247156. [PMID: 39296815 PMCID: PMC11409300 DOI: 10.1177/26331055241247156] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Accepted: 03/29/2024] [Indexed: 09/21/2024] Open
Abstract
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.
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Affiliation(s)
- Dustin R Todaro
- Center for Studies of Addiction, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Nora D Volkow
- Laboratory of Neuroimaging, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD, USA
| | - Daniel D Langleben
- Center for Studies of Addiction, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Zhenhao Shi
- Center for Studies of Addiction, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Corinde E Wiers
- Center for Studies of Addiction, Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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10
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Sue KL, Hawk K. Clinical considerations for the management of xylazine overdoses and xylazine-related wounds. Addiction 2024; 119:606-608. [PMID: 37939387 DOI: 10.1111/add.16388] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 10/11/2023] [Indexed: 11/10/2023]
Affiliation(s)
- Kimberly L Sue
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
- Program in Addiction Medicine, Yale School of Medicine, New Haven, CT, USA
- Sociobehavioral Sciences, Yale School of Public Health, New Haven, CT, USA
| | - Kathryn Hawk
- Program in Addiction Medicine, Yale School of Medicine, New Haven, CT, USA
- Department of Emergency Medicine, Yale School of Medicine, New Haven, CT, USA
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11
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Sadek SM, Khatri SN, Kipp Z, Dunn KE, Beckmann JS, Stoops WW, Hinds TD, Gipson CD. Impacts of xylazine on fentanyl demand, body weight, and acute withdrawal in rats: A comparison to lofexidine. Neuropharmacology 2024; 245:109816. [PMID: 38128606 PMCID: PMC10843705 DOI: 10.1016/j.neuropharm.2023.109816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/05/2023] [Accepted: 12/13/2023] [Indexed: 12/23/2023]
Abstract
The opioid use landscape has recently shifted to include xylazine, a veterinary anesthetic, as an adulterant in the fentanyl supply. The health impacts of xylazine as an emerging fentanyl adulterant has raised alarm regarding xylazine as a public health threat, warranting research on the impacts of xylazine on fentanyl's behavioral effects. No prior studies have evaluated the effects of xylazine on fentanyl consumption at various unit doses, fentanyl demand, or withdrawal as compared to the Food and Drug Administration-approved opioid withdrawal medication, lofexidine (Lucemyra®). This is important because lofexidine and xylazine are both adrenergic α2a (A2aR) agonists, however, lofexidine is not a noted fentanyl adulterant. Here we evaluated xylazine and lofexidine combined with self-administered fentanyl doses in male and female rats and evaluated fentanyl demand, body weight, and acute withdrawal. Consumption of fentanyl alone increased at various unit doses compared to saline. Xylazine but not lofexidine shifted fentanyl consumption downward at a number of unit doses, however, both lofexidine and xylazine suppressed fentanyl demand intensity as compared to a fentanyl alone control group. Further, both fentanyl + lofexidine and fentanyl + xylazine reduced behavioral signs of fentanyl withdrawal immediately following SA, but signs increased by 12 h only in the xylazine co-exposed group. Weight loss occurred throughout fentanyl SA and withdrawal regardless of group, although the xylazine group lost significantly more weight during the first 24 h of withdrawal than the other two groups. Severity of weight loss during the first 24 h of withdrawal was also correlated with severity of somatic signs of fentanyl withdrawal. Together, these results suggest that body weight loss may be an important indicator of withdrawal severity during acute withdrawal from the xylazine/fentanyl combination, warranting further translational evaluation.
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Affiliation(s)
- Safiyah M Sadek
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Shailesh N Khatri
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Zachary Kipp
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Kelly E Dunn
- Psychiatry and Behavioral Sciences Department, Johns Hopkins University, Baltimore, MD, USA
| | - Joshua S Beckmann
- Department of Psychology, University of Kentucky, Lexington, KY, USA
| | - William W Stoops
- Department of Behavioral Sciences, University of Kentucky, Lexington, KY, USA
| | - Terry D Hinds
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA
| | - Cassandra D Gipson
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington, KY, USA.
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Kiyatkin EA, Choi S. Brain oxygen responses induced by opioids: focus on heroin, fentanyl, and their adulterants. Front Psychiatry 2024; 15:1354722. [PMID: 38299188 PMCID: PMC10828032 DOI: 10.3389/fpsyt.2024.1354722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 01/04/2024] [Indexed: 02/02/2024] Open
Abstract
Opioids are important tools for pain management, but abuse can result in serious health complications. Of these complications, respiratory depression that leads to brain hypoxia is the most dangerous, resulting in coma and death. Although all opioids at large doses induce brain hypoxia, danger is magnified with synthetic opioids such as fentanyl and structurally similar analogs. These drugs are highly potent, act rapidly, and are often not effectively treated by naloxone, the standard of care for opioid-induced respiratory depression. The goal of this review paper is to present and discuss brain oxygen responses induced by opioids, focusing on heroin and fentanyl. In contrast to studying drug-induced changes in respiratory activity, we used chronically implanted oxygen sensors coupled with high-speed amperometry to directly evaluate physiological and drug-induced fluctuations in brain oxygen levels in awake, freely moving rats. First, we provide an overview of brain oxygen responses to physiological stimuli and discuss the mechanisms regulating oxygen entry into brain tissue. Next, we present data on brain oxygen responses induced by heroin and fentanyl and review underlying mechanisms. These data allowed us to compare the effects of these drugs on brain oxygen in terms of their potency, time-dependent response pattern, and potentially lethal effect at high doses. Then, we present the interactive effects of opioids during polysubstance use (alcohol, ketamine, xylazine) on brain oxygenation. Finally, we consider factors that affect the therapeutic potential of naloxone, focusing on dosage, timing of drug delivery, and contamination of opioids by other neuroactive drugs. The latter issue is considered chiefly with respect to xylazine, which strongly potentiates the hypoxic effects of heroin and fentanyl. Although this work was done in rats, the data are human relevant and will aid in addressing the alarming rise in lethality associated with opioid misuse.
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Affiliation(s)
- Eugene A. Kiyatkin
- Behavioral Neuroscience Branch, National Institute on Drug Abuse–Intramural Research Program, National Institutes of Health, DHHS, Baltimore, MD, United States
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Hays HL, Spiller HA, DeRienz RT, Rine NI, Guo HT, Seidenfeld M, Michaels NL, Smith GA. Evaluation of the relationship of xylazine and fentanyl blood concentrations among fentanyl-associated fatalities. Clin Toxicol (Phila) 2024; 62:26-31. [PMID: 38353935 DOI: 10.1080/15563650.2024.2309326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 01/18/2024] [Indexed: 03/01/2024]
Abstract
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.
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Affiliation(s)
- Hannah L Hays
- Central Ohio Poison Center, Nationwide Children's Hospital, Columbus, OH, USA
| | - Henry A Spiller
- Central Ohio Poison Center, Nationwide Children's Hospital, Columbus, OH, USA
| | - Rebecca T DeRienz
- Franklin County Coroner's Office, Franklin County Forensic Science Center, Columbus, OH, USA
| | - Natalie I Rine
- Central Ohio Poison Center, Nationwide Children's Hospital, Columbus, OH, USA
| | - Han-Tian Guo
- Franklin County Coroner's Office, Franklin County Forensic Science Center, Columbus, OH, USA
| | - Meagan Seidenfeld
- Department of Chemistry, University of South Florida, Tampa, FL, USA
| | - Nichole L Michaels
- Center for Injury Research and Policy, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Gary A Smith
- Center for Injury Research and Policy, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
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Mai T, Zhang Y, Zhao S. Xylazine Poisoning in Clinical and Forensic Practice: Analysis Method, Characteristics, Mechanism and Future Challenges. TOXICS 2023; 11:1012. [PMID: 38133413 PMCID: PMC10748319 DOI: 10.3390/toxics11121012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 12/07/2023] [Accepted: 12/09/2023] [Indexed: 12/23/2023]
Abstract
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.
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Affiliation(s)
- Tingting Mai
- Faculty of Forensic Medicine, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510275, China;
- Guangdong Province Translational Forensic Medicine Engineering Technology Research Center, Guangzhou 510275, China
| | - Youyou Zhang
- Department of Geriatric Neurology, The Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710004, China;
| | - Shuquan Zhao
- Faculty of Forensic Medicine, Zhongshan School of Medicine, Sun Yat-Sen University, Guangzhou 510275, China;
- Guangdong Province Translational Forensic Medicine Engineering Technology Research Center, Guangzhou 510275, China
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Acosta-Mares P, Violante-Soria V, Browne T, Cruz SL. Xylazine potentiates the lethal but not the rewarding effects of fentanyl in mice. Drug Alcohol Depend 2023; 253:110993. [PMID: 37883846 DOI: 10.1016/j.drugalcdep.2023.110993] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 10/12/2023] [Accepted: 10/14/2023] [Indexed: 10/28/2023]
Abstract
BACKGROUND Fentanyl is commonly laced with xylazine. People who use this combination report heightened effects, but it also increases death risk. Although no medication has been approved to counteract overdoses produced by fentanyl and xylazine, naloxone is frequently used. This paper studies the preclinical rewarding and lethal effects of fentanyl combined with xylazine and the efficacy of yohimbine or naloxone to prevent death. METHODS Male Swiss Webster mice were treated with (in mg/kg, i.p.) xylazine (0.3, 1, 3, or 5.6), fentanyl (0.01, 0.3, or 0.1), or 1 xylazine plus 0.01 (non-effective) or 0.1 (effective) fentanyl doses during the conditioned-place preference (CPP) test. In addition, independent groups received (in mg/kg, i.p.): xylazine (31.6, 60, 74.2, or 100), fentanyl (3.1 or 10), or both substances at two doses: 31.6 xylazine + 3.1 fentanyl, or 60 xylazine + 10 fentanyl to analyze lethal effects. We determined whether yohimbine or naloxone (each medication tested at 10 or 30mg/kg) could prevent the lethality produced by fentanyl/xylazine combinations. Female mice were also tested in key experiments. RESULTS Xylazine neither induced CPP nor altered fentanyl's rewarding effects. In contrast, lethality was potentiated when fentanyl was combined with xylazine. Naloxone, but not yohimbine, effectively prevented the lethality of the fentanyl/xylazine combinations. CONCLUSIONS At the doses tested, xylazine does not increase the rewarding effect of fentanyl on the CPP in male mice but potentiates the risk of fatal overdose in male and female mice. A high naloxone dose prevents death induced by coadministration of fentanyl and xylazine in both sexes.
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Affiliation(s)
- Palmira Acosta-Mares
- Department of Pharmacobiology, Center for Research and Advanced Studies (Cinvestav), Mexico City, Mexico
| | - Valeria Violante-Soria
- Department of Pharmacobiology, Center for Research and Advanced Studies (Cinvestav), Mexico City, Mexico
| | - Thom Browne
- Colombo Plan Secretariat, Drug Advisory Program, Colombo, Sri Lanka
| | - Silvia L Cruz
- Department of Pharmacobiology, Center for Research and Advanced Studies (Cinvestav), Mexico City, Mexico.
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D'Orazio J, Nelson L, Perrone J, Wightman R, Haroz R. Xylazine Adulteration of the Heroin-Fentanyl Drug Supply : A Narrative Review. Ann Intern Med 2023; 176:1370-1376. [PMID: 37812779 DOI: 10.7326/m23-2001] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/11/2023] Open
Abstract
Xylazine is an animal sedative, approved by the U.S. Food and Drug Administration, that is commonly used in veterinary medicine and is not approved for human use. Since 2016, xylazine has consistently appeared in the illicitly manufactured fentanyl supply and has significantly increased in prevalence, likely due to its low cost, easy availability, and presumed synergistic psychoactive effect. Clinical experience along with the available pertinent research were used to review xylazine adulteration of the drug supply and provide guidance on the care of patients exposed to xylazine. This review discusses xylazine pharmacology, animal and human clinical effects, and what is known to date about care of patients experiencing acute overdose, xylazine-fentanyl withdrawal, and xylazine-associated wounds.
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Affiliation(s)
- Joseph D'Orazio
- Cooper University Healthcare, Camden, New Jersey (J.D., R.H.)
| | - Lewis Nelson
- Rutgers New Jersey Medical School, Newark, New Jersey (L.N.)
| | | | - Rachel Wightman
- Alpert Medical School of Brown University, Providence, Rhode Island (R.W.)
| | - Rachel Haroz
- Cooper University Healthcare, Camden, New Jersey (J.D., R.H.)
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