Selected Topics: Toxicology
Xylazine Exposures Reported to Texas Poison Centers

https://doi.org/10.1016/j.jemermed.2015.09.051Get rights and content

Abstract

Background

Xylazine is a sedative, analgesic, anesthetic, and central muscle relaxant approved for animals but not humans. Although xylazine is an emerging drug of abuse, there are limited data on potentially adverse exposures to the drug.

Objectives

The intent of this study was to describe potentially adverse xylazine exposures reported to a large poison center system.

Methods

All xylazine exposures reported to Texas poison centers between 2000 and 2014 were included. The distribution of cases by select variables was determined.

Results

Of 76 total cases, 93% of the patients were ≥20 years of age, and 54% were male. Fifty-one percent of the exposures occurred by injection, 28% by ingestion, 16% were dermal, 14% were ocular, and 3% by inhalation. Sixty-four percent of the exposures were unintentional, 32% were intentional, and 1% each was related to malicious use and adverse reaction. Sixty-seven percent of the patients were already at or en route to a health care facility when the poison center was contacted, 21% were managed on-site, and 9% were referred to a health care facility. The most common clinical effects were drowsiness or lethargy (47%), bradycardia (20%), hypotension (11%), hypertension (9%), puncture or wound (8%), and slurred speech (8%).

Conclusion

Xylazine exposures tended to involve patients who were adult males, exposures were typically unintentional; and most often occurred by injection. Most of the patients were already at or en route to a health care facility when a poison center was contacted. The most frequently reported adverse effects were cardiovascular or neurologic in nature.

Introduction

Xylazine is a partial alpha-2 adrenergic receptor agonist with characteristics similar to phenothiazines and clonidine 1, 2. It acts as a sedative, analgesic, anesthetic, and central muscle relaxant (3). Xylazine is not approved by the United States (US) Food and Drug Administration (FDA) for human use in the United States, but is approved for use in dogs, cats, horses, and other large mammals (3). It is typically administered by injection. Xylazine is an emerging drug of abuse. It has been reported as an adulterant of heroin and may be used with other drugs, such as cocaine 3, 4, 5, 6, 7, 8.

There is limited information on the effects of xylazine in humans. A study that reviewed the literature from 1966 to 2013 found 43 reported cases of human exposure (3). These included accidental and intentional exposures to the drug. Adverse effects reported with the human exposures to xylazine in this review included central nervous system depression, hypotension, bradycardia, tachycardia, respiratory depression, miosis, hyperglycemia, and hypothermia (3). Deaths of people who have used xylazine have been reported 4, 9. No antidote exists; treatment recommendations include supportive care (3).

A limitation of the published review is that it included xylazine exposures from a number of different data sources (3). The objective of this study was to describe potentially adverse exposures to xylazine in humans reported to a single data source.

Section snippets

Methods

This retrospective descriptive study used data collected by the Texas Poison Center Network (TPCN). The TPCN is a system of six poison centers that together service the entire state, a current population of over 26 million. All poison centers in the TPCN use a common electronic database to collect information on all calls in a consistent manner. The data variables and allowable codes in this database were standardized by the American Association of Poison Control Centers (AAPCC) (10).

All

Results

Between 2000 and 2014, there were 76 xylazine exposures reported to the TPCN. Twenty-eight (36.8%) of the exposures involved other substances. The most frequently reported other substances were ketamine (n = 9), tiletamine and zolazepam in combination (n = 5), alcohol (n = 3), detomidine (n = 3), butorphanol (n = 2), cocaine (n = 2), and pentobarbital and phenytoin in combination (n = 2). Heroin was not reported in any xylazine exposure.

The annual number of cases ranged from 1 to 10, without

Discussion

This study describes 76 xylazine exposures reported to Texas poison centers over a 14-year period. Review of the literature failed to find as large a number of exposures reported from a single data source.

The patients were predominantly adult, with no exposures reported among children who were <11 years of age, and the majority were male.

Many of the xylazine exposures probably occurred because of accidents during normal use of the drug. This is supported by the observation that >50% of the

Conclusion

Reported xylazine exposures tended to involve adult male patients, were unintentional,and occurred via injection. Most of the patients were already at or en route to a health care facility when a poison center was contacted. The most frequently reported adverse effects were cardiovascular or neurologic in nature.

Article Summary

1. Why is this topic important?

  1. Although the veterinary drug xylazine is an emerging drug of abuse, there are limited data on potentially adverse exposures to the drug in humans.

2. What does this study attempt to show?
  1. This study describes potentially

References (10)

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    Xylazine is a veterinary tranquilizer, which is not approved for human use in the United States, but is commonly used for sedating large animals (Reyes et al., 2012; Ruiz-Colón et al., 2014). Although human intoxication with xylazine has been reported sporadically over the past several decades in a number of case studies (Ruiz-Colón et al., 2014; Forrester, 2016), it was first described as a more prevalent additive in the unregulated drug supply of Puerto Rico (Reyes et al., 2012; Rodríguez et al., 2008; Torruella, 2011). It was also noted in the literature describing drug overdose deaths in Philadelphia as early as 2006, yet it did not appear in high prevalence at that time (Wong et al., 2008).

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The Department of State Health Services institutional review board considers this analysis exempt from ethical review.

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