An animal tranquilizer called medetomidine has been linked to a recent rise in overdoses in Illinois, Michigan and Pennsylvania.

Another powerful animal tranquilizer has made its way into street drugs, added to illicit fentanyl and other opioids to prolong a user’s high.

The drug, called medetomidine, is linked to a recent spate of deadly overdoses throughout the Midwest and Northeast. It dramatically slows down breathing, heart rate, blood pressure and decreases activity in the brain and spinal cord. It’s not meant for use in people.

“It’s really concerning, the types of contaminants that we are seeing,” said Dr. Natasha Bagdasarian, chief medical executive of the Michigan Department of Health and Human Services. “Drugs are becoming deadlier.”

Medetomidine is more potent than a similar animal sedative, xylazine, or “tranq,” that’s become widespread in the U.S. over the past several years.

NPS Discovery, a group that researches illegal drugs, reported finding medetomidine in Maryland as early as July 2022.