'In her shattered Philadelphia neighborhood, and increasingly in drug hot zones around the country, an animal tranquilizer called xylazine — known by street names like “tranq,” “tranq dope” and “zombie drug” — is being used to bulk up illicit fentanyl, making its impact even more devastating.'

https://www.nytimes.com/2023/01/07/health/fentanyl-xylazine-drug.html