Horse tranquilizer crops up in overdose deaths around US

A horse tranquilizer drug often found mixed with opioids is increasingly involved in overdose deaths in some U.S. states.

The drug, called xylazine, is a sedative used in veterinary medicine, and it is not approved for use in humans. Recently, the tranquilizer began popping up in the U.S. illegal drug supply, frequently in combination with heroin or fentanyl (both types of opioids), a mixture sometimes referred to as “tranq dope,” Live Science previously reported.