A deadly new street drug caught the U.S. off guard. Experts say it'll happen again

https://www.npr.org/2023/06/17/ [login to see] /tranq-xylazine-fentanyl-street-drug-heroin-overdose
Public health and law enforcement agencies around the U.S. are scrambling to blunt the impact of xylazine, a deadly new threat to Americans who use street drugs.

That effort is complicated — some critics say crippled — by the fact that no one's sure who's mixing the dangerous chemical into fentanyl, methamphetamines and other street drugs. It's also unclear why they're doing it.

"Why has it gone national? I don't know why. Tough question out of the gate," said Dr. Nabarun Dasgupta, a researcher at the University of North Carolina who tests street drugs collected around the country.

Xylazine, or "tranq," is a horse tranquilizer used by the veterinary industry. Dasgupta says the mystery around it points to a wider public health problem: State and federal agencies lack the capacity to identify and track new drug threats in real time.