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.