U.S. authorities speak of an emerging threat.
A new drug that has hit the market is wreaking havoc in the country. Nicknamed the "zombie drug," xylazine is even more dangerous than fentanyl. It is now thought to be responsible for one-third of overdose deaths in the United States. It can cause respiratory problems, heart problems and can even cause coma. The city of Philadelphia has become the epicenter of this new scourge. The United States, which is already facing an epidemic of opioid overdoses, has sounded the alarm.