It’s a centrally acting alpha 2 adrenergic agonist sedative (it’s not a tranquilizer; tranquilizers do not affect consciousness) commonly used in large animal veterinary medicine. We’ve had to start keeping ours in safes at the request of state police; I don’t live in any of the states mentioned in the article. It won’t get you high, but it will make you sleepy and has short-acting analgesic effects. Supposedly it potentiates the high of heroin and methamphetamine with how it interacts with them. Because it’s not a controlled substance it’s historically not been as well-secured as opioids (it’s also not uncommon for farriers and horse owners to illegally acquire and use it).

Detomidine or dexmedetomidine are in the same class of drugs. There’s a huge variation in species response to individual alpha 2 agonists. There’s a few anecdotes of veterinarians accidentally injecting themselves with xylazine; they usually end up waking up in the hospital hours or days later. And that’s with a known dose and immediate transport.

Because xylazine is labeled for large animal use the formulations are somewhat concentrated (100mg/mL for horses; usually 20mg/mL for cattle) and the dose for a horse is small (~1.5-2mL).

There are reversal agents for alpha 2 agonists (atipamezole and yohimbine), but not for humans. Atipamezole is only labeled for veterinary use (although it has been evaluated in humans). Veterinary yohimbine has been on backorder for years.