Xylazine is an animal tranquilizer increasingly being found in illicit drugs like heroin and fentanyl.
This veterinary medication is not approved for human use but is linked to growing overdose deaths across the United States.
Key Facts:
- Xylazine is a veterinary medication used to sedate large animals like horses and cattle. It is not approved for use in humans.
- Traces of xylazine are being found in heroin, fentanyl and other illicit opioids at rising rates, especially in the Northeast U.S.
- Xylazine may be added to “cut” or adulterate illicit opioids to prolong the high from short-acting fentanyl.
- Overdose deaths involving xylazine rose 20-fold from 2015 to 2020. Xylazine was found in 6.7% of overdose deaths in 2020.
- Xylazine is linked to serious health risks like skin wounds, gangrene and overdoses resistant to the opioid antidote naloxone.
Source: Drug Alcohol Depend. 2022
What is Xylazine?
Xylazine is a veterinary medication that is used to sedate and relax large animals like horses, cows and deer before medical procedures.
It is in a class of medications called alpha-2 adrenergic agonists that work by depressing the central nervous system. Xylazine causes sedation, muscle relaxation and reduced pain perception.
While xylazine is approved for animal use, it is not approved for use in humans.
Illicit use of xylazine emerged in Puerto Rico over a decade ago, where people reported using it with opioids like heroin for its sedative effects.
More recently, xylazine has been increasingly found in illicit drugs like heroin and fentanyl in cities across the Northeast U.S., indicating its rise as an additive in the unregulated drug supply.
Why is Xylazine Added to Illicit Drugs?
According to people who use illicit opioids, xylazine may be added to drugs like heroin and fentanyl to “cut” or dilute the drug as well as prolong the high.
Fentanyl provides a euphoric high but has a very short duration of action, causing the high to wear off in less than an hour. This prompts more frequent dosing and injections.
Xylazine has sedative effects that can lengthen the effects of short-acting fentanyl when the drugs are used together.
People who inject drugs report seeking out opioid products believed to contain xylazine for its ability to “give fentanyl legs” or extend the duration of the high.
However, an overabundance of xylazine can lead to excessive sedation.
The Rise of Xylazine in Overdose Deaths
While xylazine has appeared sporadically in overdose deaths over the past 15 years, autopsy and toxicology reports show increasing xylazine detection over the last several years:
- Xylazine-involved overdose deaths rose nearly 20-fold between 2015 and 2020.
- In 2015, xylazine was detected in just 0.36% of overdose deaths.
- By 2020, this grew to 6.7% of overdose fatalities, a dramatic increase.
- From 2019 to 2020 alone, xylazine detection jumped by 45%.
Geographic Trends
The highest rates of xylazine detection are in northeastern states like Pennsylvania, Maryland and Connecticut. This mirrors the trajectory of fentanyl spread across the U.S. in recent years.
- In Philadelphia, xylazine was detected in 26% of overdose deaths in 2020.
- In Maryland and Connecticut, xylazine was found in 19% and 10% of overdose deaths, respectively.
- Lower levels of xylazine overdoses are seen in southern and western states.
Links to Fentanyl
There appears to be a strong ecological relationship between xylazine and illicit fentanyl.
Among overdose deaths involving xylazine:
- Fentanyl was present in 98% of cases.
- 45% also involved cocaine.
- 28% involved benzodiazepines like Xanax.
- 23% involved heroin.
This indicates xylazine is commonly being added to fentanyl and is part of a dangerous pattern of polysubstance drug use.
Health Risks of Xylazine
While more research is needed, xylazine poses several health risks:
Skin wounds – Xylazine is linked to skin wounds, abscesses and necrosis, especially with missed injections into the skin and soft tissues. Harm reduction workers note an increase in severe skin infections.
Gangrene – Xylazine may cause tissue damage through reduced oxygen supply, resulting in gangrene and loss of limbs in some cases.
Naloxone-resistant overdose – Xylazine causes sedation through non-opioid pathways in the brain. This may render overdoses partially resistant to the opioid overdose reversal drug naloxone.
Conclusion: Xylazine usage increasing…
The animal tranquilizer xylazine is an emerging adulterant in illicit opioids like heroin and fentanyl.
While more research is needed, current death investigations and community reports suggest xylazine is spreading across the unregulated drug supply with serious health consequences.
Improved surveillance and toxicology testing is needed to track xylazine and other new synthetic additives.
Harm reduction services like wound care and drug checking may help mitigate risks to people who use drugs.
References
- Study: Xylazine spreads across the U.S.: A growing component of the increasingly synthetic and polysubstance overdose crisis
- Authors: Joseph Friedman et al. (2022)
