Xylazine: the animal tranquilizer rewriting the American overdose map

A sedative developed for horses and cattle has become one of the most dangerous additions to the American drug supply. On the street it is called “tranq,” and it is now turning up mixed into illicit fentanyl in nearly every state — deepening overdoses and leaving survivors with wounds that can cost them their limbs.

What xylazine is

Xylazine is a veterinary sedative and pain reliever approved by the FDA for animal use only; it has never been approved for people. Critically, it is not an opioid. That single fact shapes everything about how it behaves in the drug supply and how an overdose involving it has to be handled.

Why it is in the fentanyl supply

In April 2023 the White House Office of National Drug Control Policy took the unprecedented step of designating fentanyl adulterated with xylazine an emerging threat to the United States, followed by a national response plan that July. The DEA reports that it has seized fentanyl-xylazine mixtures in 48 of 50 states. Xylazine appears to be used to extend or intensify fentanyl's effects — at a serious cost to the people who take it.

The wounds

One of xylazine's most feared consequences is severe skin ulceration and tissue death that can appear anywhere on the body, not only at injection sites. The CDC warns that these necrotic wounds can progress to the point of requiring amputation. They are a distinct harm from overdose itself, and they can affect people regardless of how the drug is used.

Why naloxone still matters

Because xylazine is not an opioid, naloxone cannot reverse its sedative effects. But naloxone should still be given in any suspected overdose, because fentanyl is almost always present alongside it and naloxone does reverse the fentanyl. The guidance is unchanged: give naloxone, support breathing, and call emergency services — the presence of xylazine does not make naloxone useless, it makes the overdose harder.

The numbers

The spread has been fast. In one multi-city analysis cited by the CDC, xylazine was detected in under 1% of overdose deaths in 2015 and in roughly 7% by 2020, and federal surveillance has tracked illicitly manufactured fentanyl deaths with xylazine climbing across the country since. It is a reminder that the overdose crisis is not static — the supply keeps changing underneath it.