Synthetic opioids mixed with powerful animal tranquilizers are fueling a deepening overdose crisis across the United States, according to reporting from Columbus, Ohio and Chicago.

Fentanyl, a man-made opioid 50 to 100 times more potent than heroin, is now routinely combined with substances like xylazine and medetomidine, veterinary tranquilizers that extend the high but prevent naloxone from reversing overdoses. These drug cocktails are manufactured in American basements and bathtubs, making them difficult to predict or counteract.

Overdose deaths peaked at 110,000 Americans in 2022, mostly from opioids, declining to around 70,000 last year. However, the nature of the crisis has shifted. In Franklin County, which includes Columbus, 78 percent of fatal overdoses in the last 12 months involved stimulants, according to Scott Sanders, who runs Hope Dealers, a recovery group. Sanders is almost 10 years sober and works with the Centers for Disease Control and Prevention on a drug sampling program.

The new threat targets users who believe they are purchasing crack cocaine but receive fentanyl or opioid blends instead. A recovery group member identified only as Tonya described losing her nephew to an overdose while she was simultaneously overdosing from crack cocaine spiked with fentanyl. On the street, this is called a "hot dose."

Xylazine causes necrotic skin ulcers that can extend to bone and are difficult to treat. Because naloxone, the nasal spray that reverses opioid overdoses, does not work against animal tranquilizers, standard overdose intervention fails. One recovery group member required paramedics to administer naloxone four times before it worked, after tranquilizers had been added to his fentanyl dose.

Sanders notes that overdose deaths among Black men in Ohio are increasing. He says the drug supply is now mixed and unpredictable, shifting the composition of street drugs faster than public health response can track.