Xylazine is not currently a controlled substance but has played a role in an increasing number of heroin, fentanyl and cocaine overdose deaths.

The drug xylazine has been in the headlines due to its role in increasing overdose deaths. In 2019, the Centers for Disease Control and Prevention found xylazine in 5.8% of overdose deaths. During the first six months of 2020, that number almost doubled to 11.4%.

Drug traffickers are now using the sedative xylazine as an adulterant for other illicit drugs, mixing it in to increase or change the effects. People who use drugs like heroinfentanyl or cocaine adulterated with xylazine are increasing their risk for a fatal drug overdose, often without knowing they’re taking the sedative.

Article at a Glance

  • Xylazine is an FDA-approved sedative for animal use but is not approved for use in humans.
  • Xylazine is commonly added to heroin, fentanyl, and cocaine and has been implicated in increasing overdose deaths.
  • Even a tiny amount of xylazine can lead to harmful side effects and a fatal overdose, and many people may not even realize they are taking it.

What Is Xylazine or “Tranq”?

Xylazine is a sedative used in animals that can double as a muscle relaxant and pain reliever. Although the drug is sometimes known as a horse tranquilizer, xylazine is used to treat a wide variety of animals, including cats, dogs, cattle, sheep, horses, deer, elk and even rats.

Identifying Xylazine

Xylazine is manufactured as a liquid and comes inside a vial. It is available in strengths of 20, 100, and 300 milligrams per milliliter. The drug also comes in bulk by the gram as a powder veterinary pharmacies use to compound drugs for animal use.

Xylazine can be hard to identify, especially when it is mixed with another substance: it is a common additive in illicit drugs like cocaine, heroin and fentanyl.

Many different street names exist for the drug. These include:

What Does Xylazine Do To Humans?

Similar to its action in animals, xylazine acts as a central nervous system depressant and sedative in humans. Criminals have even used the drug to induce sleep in their victims. Little is known about the drug’s addiction risks at this time, and it is not currently classified as a controlled substance.

Some people who abuse stimulants like cocaine use xylazine (with or without heroin) as a component in a speedball. This means that they mix a depressant like xylazine or heroin with cocaine to increase a drug high and reduce the crash symptoms. However, many people aren’t even aware they are taking the drug as it is commonly added to other illicit drugs like heroin.

In animals, xylazine tends to work within a few minutes and lasts up to four hours. Little data is available about how long the drug lasts in humans.

Common Side Effects

It can be hard to know if a person is using xylazine because the side effects are similar to those of other central nervous system depressants. Common xylazine side effects in humans include:

  • Blurred vision
  • Confusion
  • Sleepiness
  • Problems walking
  • Low blood pressure
  • Small pupils
  • High blood sugar
  • Skin necrosis
  • Slow heartbeat
  • Slow breathing
  • Unconsciousness

It can take very little xylazine to experience harmful effects. Doctors have found these side effects in people who have a xylazine blood concentration between 30 and 4,600 nanograms (one billionth of a gram) per milliliter.

Withdrawal Symptoms/Implications

Little data is available about withdrawal from xylazine. Unfortunately, fatal xylazine overdoses are common, so there have been few opportunities to study the withdrawal symptoms of someone who used xylazine long-term. Some experts theorize that the drug may have withdrawal symptoms similar to other sedatives like benzodiazepines.

Xylazine’s Overdose Risk

One of the big overdose risks of xylazine is that people may not even realize they are taking it. One study showed that 22% of street drug users who tested positive for xylazine had no idea they had taken it. This is likely because xylazine is commonly added to illicit drugs like cocaine, heroin, and fentanyl to increase or impact their effects.

Further, xylazine can cause an overdose whether you inject it, inhale it or swallow it. The amount of xylazine in people who have had a fatal overdose ranges widely from a mere trace amount up to 16,000 nanograms per milliliter. It is possible for even a tiny amount of xylazine to contribute to an overdose death, so doctors cannot say for sure how much xylazine it takes to overdose. This means that no amount of xylazine is safe.

Xylazine Overdose Symptoms

Doctors have limited information on the specific overdose symptoms of xylazine. However, they appear to be similar to the drug’s common side effects, although more intense. For this reason, even nonfatal xylazine overdoses typically need to be treated in a hospital setting. Xylazine overdose has been found to cause symptoms like:

  • Small pupils
  • Low body temperature
  • Dry mouth
  • Slow heartbeat
  • Unconsciousness
  • Slowed or stopped breathing (which is often fatal)

One barrier to treating a xylazine overdose is that although the drug can be found in blood and urine, it is not included in routine drug tests. This means it may take time for a doctor to realize that a person is having a xylazine overdose.

Xylazine Reversal Drug

There is no reversal drug for xylazine overdose at this time. Because xylazine is not an opioid, the opioid reversal agent naloxone will not work on it. However, an overdose can be treated in the hospital with supportive care, meaning that the person’s symptoms are addressed. Some doctors recommend treating a person experiencing a xylazine overdose with IV fluids, atropine, and intubation if needed.

If you or your loved one is using drugs like heroin, fentanyl or cocaine, you are at a higher risk for a fatal xylazine overdose, often without knowing you’re taking it. The Recovery Village can help you enter lifelong recovery from drug addiction with evidence-based, compassionate addiction treatment that is personalized to your unique needs. Contact us today to discuss our treatment programs and how they can help.

Melissa Carmona
Editor – Melissa Carmona
As the content manager at Advanced Recovery Systems, Melissa Carmona puts years of writing and editing experience to work helping people understand substance abuse, addiction and mental health disorders. Read more
Jessica Pyhtila
Medically Reviewed By – Dr. Jessica Pyhtila, PharmD
Dr. Jessica Pyhtila is a Clinical Pharmacy Specialist based in Baltimore, Maryland with practice sites in inpatient palliative care and outpatient primary care at the Department of Veteran Affairs. Read more
Sources

Kidron, Ariel; Nguyen, Hoang. “Phenothiazine.” StatPearls, July 25, 2021. Accessed October 8, 2021.

Drug Enforcement Administration. “Controlled Substances.” August 27, 2021. Accessed October 8, 2021.

Drug Enforcement Administration. “Xylazine.” February 2021. Accessed October 8, 2021.

U.S. National Library of Medicine. “Xylazine Injection, Solution.” May 15, 2020. Accessed October 8, 2021.

U.S. National Library of Medicine. “Xylazine Hydrochloride, Powder.” October 14, 2019. Accessed October 8, 2021.

Reyes, JC; Negrón, JL; Colón, HM; et al. “The Emerging of Xylazine as a New Drug of Abuse and its Health Consequences among Drug Users in Puerto Rico.” Journal of Urban Health, March 6, 2012. Accessed October 8, 2021.

Gallanosa, AG; Spyker, DA; Shipe, JR; Morris, DL. “Human xylazine overdose: a comparative review with clonidine, phenothiazines, and tricyclic antidepressants.” Clinical Toxicology, June 1981. Accessed October 8, 2021.

Mobile Health Management Services. “What Are the Different Drug Panels?” Accessed October 8, 2021.

Capraro, AJ; Wiley, JF; Tucker, JR. “Severe intoxication from xylazine inhalation.” Pediatric Emergency Care, December 2001. Accessed October 8, 2021.

Ruiz-Colón, Kazandra; Chavez-Arias, Carlos; Díaz-Alcalá, José Eric; Martínez, María A. “Xylazine intoxication in humans and its importance as an emerging adulterant in abused drugs: A comprehensive review of the literature.” Forensic Science International, July 2014. Accessed October 8, 2021.

Thangada, Shobha; Clinton, Heather A.; Ali, Sarah; et al. “Notes from the Field: Xylazine, a Veterinary Tranquilizer, Identified as an Emerging Novel Substance in Drug Overdose Deaths — Connecticut, 2019–2020.” Centers for Disease Control and Prevention, September 17, 2021. Accessed October 8, 2021.

National Drug Early Warning System. “COVID-19 and Drug-Related Trends.” March 12, 2021. Accessed October 8, 2021.

McNinch, James; Maguire, Michael; Wallace, Lisa; Care, Christiana. “A Case of Skin Necrosis Caused by Intravenous Xylazine Abuse.” Journal of Hospital Medicine, 2021. Accessed October 8, 2021.

Medical Disclaimer

The Recovery Village aims to improve the quality of life for people struggling with substance use or mental health disorder with fact-based content about the nature of behavioral health conditions, treatment options and their related outcomes. We publish material that is researched, cited, edited and reviewed by licensed medical professionals. The information we provide is not intended to be a substitute for professional medical advice, diagnosis or treatment. It should not be used in place of the advice of your physician or other qualified healthcare providers.