Lab reports from drug busts increasingly list a substance most people had never heard of a few years ago: xylazine. Known on the street as “tranq” or “tranq dope,” it’s an animal sedative that has been mixed into the illicit fentanyl supply, and it has created new dangers for people who use drugs and new challenges for first responders.
What xylazine is
Xylazine is a veterinary drug used to sedate and relax large animals such as horses and cattle. It is approved by the FDA for animal use only. It is not an opioid. It belongs to a different class of drugs (alpha-2 adrenergic agonists) that slow the central nervous system, causing deep sedation, slowed breathing, low blood pressure, and slowed heart rate.
Why it’s being mixed with fentanyl
Xylazine is cheap and can extend the sedating effects of fentanyl. Traffickers use it as an additive to stretch or alter their product. Many people who use fentanyl don’t know xylazine is in it.
It first became widespread in the Philadelphia drug supply and spread to other parts of the country over the following years. It now appears in lab results from seizures in many states.
A national “emerging threat”
In April 2023, the White House Office of National Drug Control Policy designated fentanyl adulterated or associated with xylazine as an emerging threat to the United States. It was the first time any substance received that designation under federal law, which triggered a national response plan covering testing, treatment, data collection, and supply reduction.
Why naloxone doesn’t fully work
Naloxone (Narcan) reverses opioid overdoses. Because xylazine is not an opioid, naloxone doesn’t reverse its effects. Someone who overdosed on a fentanyl-xylazine mix may start breathing again after naloxone yet remain heavily sedated.
Health officials still strongly recommend giving naloxone in any suspected overdose, because fentanyl is almost always involved and naloxone can reverse that part. Calling 911 and supporting breathing are critical. For more on how opioids compare, see fentanyl vs. heroin vs. carfentanil.
The wounds
One of xylazine’s most alarming effects is severe skin wounds. People who repeatedly use xylazine-containing drugs can develop painful ulcers that may become infected and, in serious cases, lead to amputation. These wounds can appear even away from injection sites. Medical providers have had to develop specialized wound care approaches for patients exposed to xylazine.
Withdrawal
Xylazine dependence can complicate withdrawal. People who are dependent on both fentanyl and xylazine may experience withdrawal symptoms that standard opioid treatments don’t fully address, such as severe anxiety and restlessness. Treatment providers have been adjusting care accordingly.
Testing for it
Fentanyl test strips don’t detect xylazine. Separate xylazine test strips are available in many places. In a criminal case, crime labs identify xylazine through standard laboratory analysis of seized drugs (see what happens to seized drugs).
Is xylazine illegal?
Because xylazine is an important veterinary medicine, legal efforts have focused on controlling its illicit use while protecting access for veterinarians, farmers, and ranchers. Several states have added xylazine to their controlled substance lists, and federal lawmakers have pursued legislation targeting illicit xylazine. Laws vary, so the charges in a xylazine-related case depend heavily on the state and on whether fentanyl was involved, which carries its own heavy federal penalties.
Why it shows up in our coverage
When a bust’s lab results mention xylazine, it signals a drug supply with added risks: overdoses that don’t fully respond to naloxone and wounds that can cause lasting harm. We note xylazine whenever officials report it in a seizure. Browse our fentanyl busts for recent cases.
Quick facts
- Street names: tranq, tranq dope
- What it is: veterinary sedative, not approved for humans
- Is it an opioid? No
- Does Narcan reverse it? No, but give naloxone anyway because fentanyl is usually present
- Federal status: designated (with fentanyl) an emerging threat by ONDCP in April 2023
- Signature harm: severe skin wounds and heavy, prolonged sedation
Frequently asked questions
Why is xylazine called tranq?
Because it is a tranquilizer used on animals. The nickname “tranq” or “tranq dope” refers to fentanyl mixed with xylazine.
Should you give Narcan if xylazine might be involved?
Yes. Health officials recommend giving naloxone in any suspected overdose because fentanyl is usually present. Then call 911 and support the person’s breathing.
Where did xylazine first spread?
Philadelphia was one of the first places where xylazine became widespread in the drug supply before it spread to other regions.
If you or someone you know is struggling with substance use, the SAMHSA National Helpline is free, confidential, and available 24/7 at 1-800-662-4357. In an emergency, call 911.