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Xylazine (Tranq Dope)

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on May 5, 2023.

Common or street names: Tranq, Tranq dope, Sleep-cut, Philly dope, Zombie drug

What is xylazine?

Xylazine is a medicine used in veterinary (animal) medicine. It is NOT an opioid. It is a tranquilizer, sedative and pain reliever that is FDA approved ONLY for use in animal medicine. It has no FDA-approved uses for humans. In veterinary medicine, it is used as a component of diagnostic and surgical procedures in animals ranging from cats and dogs to horses and cattle.

In recent years, xylazine has been found as an adulterant in drugs of abuse often sold on the streets, such as in heroin or fentanyl. Although many of its effects are similar to opioids, chemically it is not an opioid;  therefore, naloxone is not known to be effective in reversing the toxic effects of xylazine.

Xylazine is structurally similar to a class of drugs known as phenothiazines. Xylazine also has chemical properties similar to other drugs like clonidine, levamisole and tizanidine and may have similar clinical effects. Similar to clonidine, it acts as an agonist at central alpha-2-adrenergic receptors in the brain. This causes a rapid decrease in the release of the neurotransmitters norepinephrine and dopamine. It may have effects on other receptors, but more research is needed. 

Large drug seizures of xylazine have occurred in Pennsylvania, Connecticut, Maryland, Puerto Rico and California. Xylazine was reported to be involved in 19% of all fatal drug overdose deaths in Maryland in 2021, and 10% of Connecticut overdose deaths in 2020. 

In April 2023, the White House designated xylazine an "emerging drug threat". This will allow the government to boost law enforcement, health care strategies, and data review to help fight the drug on the streets. It will also evaluation to help schedule it as a controlled substance. 

What is the history of xylazine?

Xylazine was first synthesized by Bayer in 1962 and then approved as an animal medicine by the FDA in 1972. It is a non-opioid used for its sedative, pain relieving with muscle relaxant properties in animal (veterinary) medicine. It is not approved by the FDA for use in humans.

Formerly, Bayer studied xylazine for use in humans but it was found to have serious side effects like the occurrence of very low blood pressure (severe hypotension) and severe central nervous system depressants effects.

In recent years, xylazine has been found as a component of street drugs and is complicating healthcare management of overdoses that also contain opioids. Healthcare providers should be aware of its increasing presence in illicit drugs of abuse. Patients who do not respond as expected to naloxone treatment or that have unusual necrotic skin ulcers may have been exposed to this drug.

In November 2022, the FDA released a Letter to Stakeholders and a Drug Alert to healthcare providers about the risk of xylazine exposure in humans. 

How does xylazine come?

Xylazine comes as a liquid solution for injection in 20 mg/mL, 100 mg/mL and 300 mg/mL strengths, for veterinary use only. It may be combined with other anesthetic medicines when used for animal surgery. It is typically given to animals intravenously, intramuscularly or orally. Xylazine has a rapid onset of action and its effects can last up to 4 hours in animals. 

Trade names for xylazine in veterinary medicine include: Rompun, Sedazine and AnaSed.

Xylazine is not yet controlled under the federal Controlled Substances Act. 

How do people use xylazine?

Xylazine has primarily been found as a contaminant in combination with illicit fentanyl and heroin sold on the streets. It is typically used by injection. It may be used unknowingly when injected with other street drugs, like heroin or fentanyl.

However, some people may knowingly abuse xylazine to help lengthen the euphoric effect (“high”) from fentanyl injections. People who inject drugs are at a high risk for exposure to xylazine due to its increasing prevalence on the streets.

Stimulants, such as methamphetamine and cocaine have also been combined with xylazine. There are reports of users combining it with “speedballs” (a mixture of an opioid and stimulant) to offset the unintended effects of the mixture.

Can I get addicted to xylazine?

Yes, repeated exposure to xylazine may lead to dependence, addiction and withdrawal symptoms, which may include agitation, vision changes, disabling migraines or severe anxiety when doses are decreased or stopped. These side effects may lead to continued abuse and undermine any efforts to treat an ongoing opioid use disorder (OUD).

What are the side effects of xylazine? 

Xylazine toxicity in humans may include:

In addition, it may interfere with the successful treatment of opioid use disorder (OU) and delay the management of an overdose. Death can occur in humans when used alone or as part of a multidrug overdose.

Healthcare providers should provide appropriate supportive care to patients who do not respond adequately to naloxone administration, if given. Xylazine in a polysubstance exposure may include symptoms such as low blood pressure, fast heart rate and abnormal heart rhythms. 

Severe, necrotic skin ulcers may also be a sign that repeated xylazine exposure has occurred. Wound management, antibiotics and hospitalization may be needed.

Is there a treatment for xylazine overdose in humans?

No, at this time there is no known xylazine antidote for safe and effective use in humans. Xylazine is NOT currently known to be reversed by naloxone (Narcan, Kloxxado, Zimhi, generics), an opiate antidote. Healthcare providers should provide appropriate supportive care to patients who do not respond adequately to naloxone administration. 

The serious side effects that can occur with xylazine use may not be reversed by narcotic antidote naloxone because xylazine is not an opioid. The reversal agents for xylazine that are used in animals (such as yohimbine or tolazoline) are not known to be safe or effective for a xylazine overdose in humans. Reversal agents regularly used in veterinary medicine should not be used in humans because it is not known if they are safe or effective in this population.

Routine toxicology screens do not identify xylazine and it may be difficult to determine if it is involved in an overdose without additional, more advanced analytical measures like gas chromatography–mass spectrometry (GC-MS). In addition, xylazine is rapidly removed from the body (half-life of 23 to 50 minutes), which may make detection even more difficult. 

Healthcare providers should continue to administer naloxone when they suspect an opioid overdose and consider that xylazine may be involved as a component of an overdose if the patient does not respond as expected.

How often do people use xylazine?

The full extent of xylazine use in humans is not known. From 2015 through 2020, based on forensic information from the DEA, xylazine was identified in over 3,800 reports. In 2020, there were 1,492 reports.

The National Institute on Drug Abuse reports that overdose deaths in Pennsylvania increased from 2% to 26% from 2015 to 2020. From 2019-2020, drug overdose death rates were highest in the 35 to 44 year old age group in Connecticut, 2019 – 2020. From 2019 to July 2020 in Connecticut, xylazine-associated deaths occurred primarily among males (80.9%) and non-Hispanic White persons (74%). Mortality was highest among persons aged 25–34 years (28.1%).

A study from 2022 found that Illicitly-manufactured fentanyl was present in 98.4% of overdose deaths where xylazine was also present. Other drugs detected with xylazine included cocaine (45.4%), benzodiazepines (28.4%), heroin (23.3%), alcohol (19.7%), as well as gabapentin, methadone, and prescription opioids.

In addition to its use as an adulterant in illicit drugs, the DEA reports it has been used in drug facilitated crimes to induce sleep.

It is not yet known if xylazine is produced illegally or diverted from the veterinary drug supply, although reports have stated supplies are thought to originate from China, Mexico, India or Russia. The FDA is continuing to investigate the source and will report when more information is available.

The FDA encourages health care professionals and patients to report adverse events in humans associated with possible illicit xylazine exposure to FDA’s MedWatch Adverse Event Reporting program. Complete and submit the report online at; or download and complete the form, then submit it via fax at 1-800-FDA-0178.

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