Xylazine is a tranquilizer approved by the Food and Drug Administration for veterinary use. It is not approved for use in people.

“As a physician, I am deeply troubled about the devastating impact of the fentanyl-xylazine combination … I am immensely concerned about what this threat means for the nation,” White House Office of National Drug Control Policy Director Dr. Rahul Gupta said in a statement. “By declaring xylazine combined with fentanyl as an emerging threat, we are being proactive in our approach to save lives and creating new tools for public health and public safety officials and communities across the nation.”

“Xylazine is making the deadliest drug threat our country has ever faced, fentanyl, even deadlier,” DEA Administrator Anne Milgram said in a statement.

U.S. officials reported 107,735 overdose deaths between August 2021 and August 2022 from drug poisonings, according to the U.S. Centers for Disease Control and Prevention. About 66% of those deaths involved synthetic opioids such as fentanyl.

National overdose death numbers have flattened or decreased for seven consecutive months, however, “xylazine is complicating efforts to reverse opioid overdoses with naloxone and threatens progress being made to save lives and address the opioid crisis,” according to a statement from the White House Office of National Drug Control Policy.

“Following today’s public declaration, the administration will take steps to publish a whole-of-government response that includes evidence-based prevention, treatment, and supply reduction,” according to the office.