Atipamezole as an emergency treatment for overdose from highly concentrated alpha-2 agonists used in zoo and wildlife anesthesia

PROTOCOL FOR HUMAN EXPOSURE TO OPIOIDS AND CONCENTRATED MEDETOMIDINE USED IN FIELD APPLICATIONS

Wildlife professionals routinely use potent sedatives and anesthetics when chemically immobilizing wildlife and zoo species in remote environments. Accidental exposure to these prescription veterinary drugs is rare but could be rapidly fatal. Commonly used agents include opioids and α2 adrenoreceptor agonists. These drugs can be reversed with specific antagonists; however, they are often not approved for human use. The protocol created here can be used by wildlife health professionals in a field setting with basic human emergency medical response training in coordination with local Emergency Medical Services (EMS). Key components include, building local relationships between EMS and wildlife professionals, focused EMS training, administering opioid and α2 adrenergic antagonists off label, and local evacuation procedures. This framework could allow wildlife management agencies or zoos to mitigate the risk of human exposures to these commonly used drugs, significantly improving occupational safety in an otherwise high-risk environment.

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.

A case series of accidental xylazine intoxication in humans; Is there a role of naloxone as an antidote?

Xylazine is a type of sedative commonly used in veterinary medicine. It acts on the central alpha-2 receptor and suppresses norepinephrine release from the peripheral nerve terminal. It is also reported to have action on cholinergic, serotogenic, H2-histamine, dopaminergic, and opioid receptors. Once administered in animals, it causes hypotension, bradycardia, central nervous system depression, and respiratory depression. The effect will start within minutes after absorption and last up to 4 h depending on the dosage given. Till date, it is only exclusively used in animals as approved by the Food and Drug Administration. Human intoxication is uncommon, and no specific antidote is available. Naloxone, a competitive opioid receptor antagonist, was postulated to have an antidotal effect on xylazine. We report two cases of accidental human injection with xylazine. Naloxone was administered in one of the cases. Acute hypertension and mydriasis were observed; however, no apparent reversal of toxidrome was seen. This finding reveals the question regarding the efficacy and benefit of naloxone usage in xylazine intoxication. General management remains supportive of care focusing on ventilation and hemodynamics. Attending physicians should be aware of potential xylazine intoxication incidents in the area of livestock or veterinary activities.