Xylazine Exposures Reported to Texas Poison Centers.

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.

Xylazine intoxication in humans and its importance as an emerging adulterant in abused drugs: A comprehensive review of the literature.

Xylazine is not a controlled substance; it is marketed as a veterinary drug and used as a sedative, analgesic and muscle relaxant. In humans, it could cause central nervous system depression, respiratory depression, bradycardia, hypotension, and even death. There have been publications of 43 cases of xylazine intoxication in humans, in which 21 (49%) were non-fatal scenarios and 22 (51%) resulted in fatalities. Most of the non-fatal cases required medical intervention. Over recent years xylazine has emerged as an adulterant in recreational drugs, such as heroin or speedball (a cocaine and heroin mixture). From the 43 reported cases, 17 (40%) were associated with the use of xylazine as an adulterant of drugs of abuse. Its chronic use is reported to be associated with physical deterioration and skin ulceration. Literature shows some similar pharmacologic effects between xylazine and heroin in humans. These similar pharmacologic effects may create synergistic toxic effects in humans. Therefore, fatalities among drug users may increase due to the use of xylazine as an adulterant. Xylazine alone has proven harmful to humans and even more when it is combined with drugs of abuse. A comprehensive review of the literature of non-fatal and fatal xylazine intoxication cases including those in which the substance was used as adulterant is presented, in order to increase the awareness in the forensic community, law enforcement, and public health agencies.

Xylazine (veterinary sedative) use in Puerto Rico.

Human xylazine use in Puerto Rico merits particular attention for its unprecedented scale and depth. Although Puerto Rican injecting drug users (IDUs) have reported using this drug since the early 2000s, little is being done in the research and service delivery sectors as it is claimed that xylazine severely impacts the health of its users. This report provides information on xylazine use and its associated harms. Data from one semi-structured interview collected in New York City (2007-2008) as part of a larger research study with migrant Puerto Rican drug users is presented as a case study. Xylazine, a veterinary sedative, is an adulterant and complement to other drugs and its chronic use is reported to be associated with physical deterioration. Because human xylazine use has been reported in other locations outside of Puerto Rico, this substance could also emerge as an adulterant in other markets to the levels currently experienced in Puerto Rico. Research and interventions are needed to provide adequate services on the island, better understand how the use of xylazine affects its users, and to reduce the possibility of increased xylazine use on the state-side.

Systemic toxicity after an ocular exposure to xylazine hydrochloride.

There are limited reports of human overdose with the animal tranquilizer, xylazine hydrochloride. The reported effects include hypotension, bradycardia, and respiratory depression. Ocular exposures to xylazine have not been previously reported. A 38-year-old man arrived in the Emergency Department, reporting the accidental irrigation of both eyes with approximately 8 mL of xylazine (100 mg/mL) 30 min before arrival. The patient was asymptomatic. The eyes were copiously irrigated with isotonic crystalloid. Two hours after the exposure, the patient developed sinus bradycardia (40-50 beats/min), hypotension (90/60 mm Hg), and a decreased level of consciousness. The patient was admitted for observation, during which the bradycardia and hypotension were noted to persist. He remained otherwise asymptomatic. The symptoms resolved without intervention, other than i.v. fluids, approximately 25 h after the exposure. The patient was discharged home. This case demonstrates that ocular exposure to xylazine can cause systemic central nervous system and cardiovascular effects.

An unusual presentation from xylazine-ketamine.

Veterinary anesthestics have gained popularity as drugs of abuse. A case of multiple drug abuse by a 36-y-old veterinarian involved the injection of xylazine-ketamine, resulting in gastrointestinal, cardiovascular and central nervous system effects, and unexpected hypertension, tachycardia and electrocardiogram changes.

Drug abuse with inhalated xylazine.

Given the difficulty of obtaining traditionally illicit drugs, consumption is turning towards less restricted products. We report the case of an 18-year-old man, who after inhaling xylazine (a non-narcotic sedative used in veterinary medicine for analgesia, hypnosis and muscle relaxation) presented with an episode of chills and dizziness followed by sweating, gait instability, palpitations and two episodes of syncope with bradycardia and hypotension. Ten cases of toxicity caused by xylazine consumption by oral and parenteral administration (intramuscular, subcutaneous, and intravenous) have been documented in humans. In these cases, consumption was either involuntary or for suicidal or homicidal purposes, or used as an agent of drug abuse, occasionally resulting in death. We present the second documented case of toxic effects of drug abuse with inhalated xylazine.

Severe intoxication from xylazine inhalation.

We present the first documented case of overdose from xylazine inhalation. The patient developed findings consistent with alpha 2 adrenergic agonist toxicity, eg coma, miosis, apnea, bradycardia, hypothermia, and dry mouth 2 hours after exposure. Standard dose naloxone did not reverse these effects. The patient fully recovered after appropriate supportive measures. A review of prior reports of xylazine exposure is provided.

Severe intoxication with the veterinary tranquilizer xylazine in humans.

Xylazine (Rompun, Proxylaz) is a veterinary tranquilizing agent. A case of self-injection of 1.5 g xylazine by a 27-year-old farmer is reported. He subsequently became comatose, hypotensive, bradycardic, and mildly glycemic. An intensive supportive therapy including intubation and ventilation was required. The patient made a full recovery over the next 30 h. The largest concentrations measured were 4.6 mg/L in plasma, 446 mg/L in gastric fluid, and 194 mg/L in urine. The calculated plasma half-life was 4.9 h. Kinetic data correlated with clinical symptoms. Qualitative and quantitative analyses of xylazine were done by thin-layer chromatography, gas chromatography-mass spectrometry, and high-performance liquid chromatography. These methods allow the detection of small amounts substance in stomach, plasma, and urine. Liquid-liquid extraction was used for the isolation of drug. The sensitvity is high, and with these methods, a rapid analysis is possible. Xylazine intoxications in humans are rare. We describe the management of acute poisoning and present a review of xylazine toxicity in humans.

Xylazine toxicity--literature review and report of two cases.

Xylazine is a veterinary sedative, analgesic or general anesthetic. Its pharmaceutical action results in sympathetic discharge via stimulation of alpha-2-adrenoceptors. In humans, toxicity consists of central nervous system depression, bradycardia and hypotension. The dosages known to produce toxicity in humans vary from 40 mg up to 2400 mg. Because of decomposition, xylazine blood concentrations in two homicide victims were unknown; however, the concentrations in the brain, liver, and kidneys were much higher in the 23-year-old female versus the 33-year-old male victim. A bottle of xylazine found on the crime scene had a concentration of 100 mg/mL. This 50 mL bottle had 32 mL remaining. Therefore at some point in time 18 mL had been utilized. The amount of available milligrams of xylazine (1800 mg) were enough to cause toxicity in both the woman and the man. Of interest was the fact that the partially skeletonized heads were found remote from the torsos, however, the concentration of xylazine in the body tissues provided a toxicological match of which head belonged to which body. Xylazine toxicity in humans and its relationship to these homicides will be the focus of this report.

A case report of the treatment of an overdose of xylazine in a cow.

An adult Holstein cow was inadvertently administered an overdose of xylazine hydrochloride. The cow became weak, collapsed, and developed severe bradycardia and intermittent heart block. Initial therapy for cardiovascular collapse consisted of rapid infusion of large volumes of intravenous fluids and intravenous injection of atropine sulfate. Yohimbine, an alpha 2-adrenergic antagonist, and tolazoline hydrochloride, an alpha 1- and alpha 2-adrenergic antagonist, were administered intravenously as antidotes for xylazine overdose. The cow recovered but calved prematurely 4 days later.

Accidental self administration of xylazine in a veterinary nurse.

A 19 year old male veterinary nurse accidentally injected himself with 200 mg of xylazine (a muscle relaxant and sedative used in veterinary practice). He subsequently became comatose, hypotensive, bradycardic and acidotic. He required intensive supportive therapy, and made a full recovery over the next few hours. Xylazine toxicity in humans is very rare, and the effects are discussed.

Human overdose with the veterinary tranquilizer xylazine.

Three patients self-injected the veterinary tranquilizing agent xylazine (Rompun). The first patient developed mild bradycardia and hypotension, miosis, and a feeling of disorientation. The other two patients became apneic and required intubation and mechanical ventilation. Initial mild hypertension followed by mild hypotension and a mildly elevated blood glucose was seen in the second patient, whereas both the second and third patients developed mild bradycardia. Xylazine has structural similarity to the phenothiazines and pharmacological activity similar to clonidine. With increasing veterinary use, the availability and potential for human exposures may also increase.

Xylazine in human tissue and fluids in a case of fatal drug abuse.

A fatal case of multiple drug abuse in a 36-year-old veterinarian involving injection of xylazine and ingestion of alcohol and clorazepate is presented. Quantitative analysis of xylazine was by gas liquid chromatography with a nitrogen detector. Xylazine concentrations (mg/L or mg/kg) were: blood, 0.2; brain, 0.4; kidney, 0.6; liver, 0.9; lung, 1.1; omentum adipose 0.05; and urine, 7.0. Blood ethanol and nordiazepam concentrations were 380 mg/dL and 2.5 mg/L, respectively.