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Xylazine: The Emergence of a New Drug

Xylazine: The Emergence of a New Drug

You might have heard of people going to extreme lengths to get high, but have you ever heard of a horse tranquilizer high? The drug Xylazine made headlines due to its role in increased overdose deaths. In 2019 alone, Xylazine was involved in 5.8% of drug overdose deaths. That number nearly doubled to 11.4% by the first half of 2020.1 While the stats may seem small compared to other drug-related incidents, considering that Xylazine is a tranquilizer designed for large animals, we can’t help but wonder why people thought it was worth experimenting with it in the first place. 


What Is Xylazine?

Xylazine is an FDA-approved tranquilizer used for medium to large animals like sheep, horses, dogs, cats, deer, rats, and elk. It calms the animals and allows for diagnostic and surgical procedures, pain relief, or acts as a local anesthetic. The drug is available in liquid solutions at 20, 100, and 300 milligrams or milliliters.2

As a tranquilizer, Xylazine acts as a sedative with analgesic and muscle relaxant properties, meaning it can be used to either fully sedate animals or to alleviate pain. Although Xylazine is only meant to be used in veterinary medicine, horse tranquilizer abuse among humans has become a growing trend.

The drug was originally synthesized in 1962 by the pharmaceutical Bayer Company.2 Although it was first studied for its potential use as an analgesic, hypnotic, and anesthetic in humans, clinical trials were eliminated due to adverse Xylazine side effects, including hypotension and severe central nervous system depression.

Despite this, reports, alerts, and advisories indicate a recent increase in the use of Xylazine in humans for recreational purposes. Exposure to Xylazine is common among people who use heroin, fentanyl, cocaine, and other illicit drugs that are used recreationally. Both accidental and intentional exposure to Xylazine has been reported among these users.2


How Does Xylazine Work in Humans?

While Xylazine’s mechanism of action is understood in animals, studies on Xylazine’s side effects in humans are scarce. Norepinephrine is a naturally occurring chemical in the body that acts as a stress hormone and neurotransmitter (chemical messenger used by nerve cells to communicate with each other.) It’s released into the blood as a stress hormone whenever the brain perceives a threat. This may lead to increased heart rate, breathing, and other side effects.

Dopamine is another naturally occurring chemical in the brain that acts as a neurotransmitter. It’s associated with feelings of pleasure, satisfaction, and motivation. It’s released whenever we do something we enjoy, like eating. Xylazine acts as an agonist at alpha-2 adrenergic receptors, which decreases levels of norepinephrine and dopamine in the central nervous system.

This causes sedation, analgesia, and muscle relaxation. Based on its effects on animals, it’s safe to say that Xylazine acts as a central nervous system depressant and sedative in humans.


Xylazine (Horse Tranquilizer) Effects on Humans

Although Xylazine usually comes as a liquid solution, it also comes in bulk by the gram as a powder that veterinary pharmacies use to compound drugs for animal use. This drug can be hard to identify, especially when it’s used as a cutting agent in other substances with similar textures, such as cocaine, heroin, and fentanyl.

In addition to recreational use, the sedative effects of Xylazine have made it a popular method of operation among criminals who have used the drug to induce sleep in their victims. Some people who abuse stimulants like cocaine may mix it with Xylazine as a component in speedball.

Speedball refers to a mixture of a depressant and stimulant to increase the duration and intensity of a drug high. However, many cocaine and heroin users are unaware that they’re even taking Xylazine or that it’s commonly added to other drugs.

So, what does this drug do to people? Common Xylazine side effects in humans include:

  • Sedation
  • Drowsiness
  • Blurred vision
  • Confusion
  • Sleepiness
  • Impaired coordination and movement
  • Low blood pressure
  • Small or pinpoint pupils
  • High blood sugar
  • Skin necrosis (skin death)
  • Slow heartbeat
  • Slow breathing
  • Unconsciousness

It doesn’t take a high dose of Xylazine to experience adverse effects. Doctors have found side effects in people who had as little as 30 to 4,600 nanograms (one billionth of a gram) per milliliter of Xylazine in their systems.


Xylazine Overdose Risk

A major risk of Xylazine abuse is overdose. Considering that most drug users aren’t aware they’re even taking the drug, the risk of overdose and intoxication is high.

One study showed that 22% of illicit drug users who tested positive for Xylazine had no idea they’d even taken it.3 This is likely due to the drug’s common use as an additive in substances like cocaine, heroin, and fentanyl to increase the impact and duration of their side effects. Additionally, considering that this drug was designed for large mammals, it’s understandable why a possible side effect of horse tranquilizers on humans is overdose.

Furthermore, it’s often difficult for illicit drug users to tell whether the substance they’re using is laced with other drugs and how much of the drug they’re laced with. As a result, one batch of heroin might have significantly higher doses of Xylazine than another. The obscurity in potency and dosage also increases overdose risk.

The Xylazine overdose amount has ranged widely from mere traces of the drug to up to 16,000 nanograms per milliliter. This means overdose is possible even with only a tiny amount of the drug. To be clear - no amount of Xylazine is safe to take.


Illicit Drug Addiction Treatment

If you or a loved one uses drugs like heroin, fentanyl, or cocaine, you’re at a higher risk of Xylazine overdose, often without knowing it. Our Heartland rehab facility offers various Illinois addiction treatment programs for both street and prescription drugs. Starting with medically supervised detox, we treat both the physical and physiological challenges of addiction recovery to increase clients’ chances of long-term success.


Whether it’s drug or alcohol addiction treatment you need, we’re here for you. For further information about our levels of addiction care and how to get started, call Banyan Heartland today at 888-280-4763.



  1. CDC - Notes from the Field: Xylazine, a Veterinary Tranquilizer, Identified as an Emerging Novel Substance in Drug Overdose Deaths — Connecticut, 2019–2020
  2. Drug Enforcement Agency - Xylazine
  3. National Library of Medicine - The Emerging of Xylazine as a New Drug of Abuse and its Health Consequences among Drug Users in Puerto Rico


Related Reading:

How Long Does a Fentanyl High Last?

Difference Between Carfentanil and Fentanyl

Alyssa, Director of Digital Marketing
Alyssa, Director of Digital Marketing
Alyssa is the National Director of Digital Marketing and is responsible for a multitude of integrated campaigns and events in the behavioral health and addictions field. All articles have been written by Alyssa and medically reviewed by our Chief Medical Officer, Dr. Darrin Mangiacarne.