"Xylazine is approved by the U.S. Food and Drug Administration (FDA) for veterinary use only. It is available in liquid solutions at 20, 100, and 300 mg/mL."
"Xylazine is a pharmaceutical drug used for sedation, anesthesia, muscle relaxation, and analgesia in animals such as horses, cattle, and other non-human mammals. Veterinarians also use xylazine as an emetic, especially in cats. It is an analog of clonidine and an agonist at the α2 class of adrenergic receptor."
"Side effects - Xylazine overdose is usually fatal in humans.  Because it is used as a drug adulterant, the symptoms caused by the drugs accompanying xylazine administration vary between individuals."
"Recreational use - Since the early 2000s, xylazine has become popular as a drug of abuse in the United States and Puerto Rico. Xylazine's street name in Puerto Rico is anestesia de caballo, which translates to "horse anesthetic". Xylazine's street name in United States is "tranq", "tranq dope", and "zombie drug."
"Overdose - The known doses of xylazine that produce toxicity and fatality in humans vary from 40 to 2400 mg... Currently, there is no specific antidote to treat humans who overdose on xylazine. Hemodialysis has been suggested as a form of treatment, but is usually unfavorable due to the large volume of distribution of xylazine."
"Xylazine is being used to adulterate or “cut” recreational drugs, common opioids (fentanyl, heroin), and benzodiazepines, to extend the duration of the drug's effects or increase its street value. Law enforcement has identified xylazine in the unregulated fentanyl supply in West Texas."
"This drug has serious and deadly consequences and there is currently no approved drug to reverse its effects on humans. The Combating Illicit Xylazine Act is calling for xylazine to be classified as a Schedule III drug and invoke penalties on those who choose to illicitly use and distribute the drug."
"Xylazine can be picked up in a comprehensive toxicology screen (gas chromatography-mass spectrometry) but will not show on routine drugs of abuse testing."