Xylazine (Tranq Dope): The Dangerous New Adulterant

Xylazine is a veterinary sedative with no approved human use that has infiltrated the illicit drug supply across the United States.

It is most commonly found mixed with fentanyl and is known on the street as tranq, tranq dope, or the zombie drug. It is not an opioid, and naloxone will not reverse its effects. Xylazine is clinically dangerous. Every harm reduction tool and overdose response protocol built around the opioid epidemic was designed for opioids.

Xylazine operates outside those protocols entirely. A person overdosing on tranq dope may receive naloxone, regain some respiratory function from the fentanyl reversal, and still die from xylazine-induced sedation that continues uninterrupted.

Is someone you love using drugs that may contain xylazine?

Key Takeaways

• The DEA has seized xylazine and fentanyl mixtures in 48 of 50 states. In 2022, approximately 23% of fentanyl powder and 7% of fentanyl pills seized by the DEA contained xylazine, according to the DEA’s own laboratory system.
• The Biden administration formally designated fentanyl combined with xylazine as an emerging threat to the United States in April 2023, the first time the government had issued such a designation for any drug combination.
• Xylazine is not an opioid and naloxone does not reverse its effects.
• Xylazine causes severe, progressive skin wounds and tissue death (necrosis) that can appear anywhere on the body, not only at injection sites, and can lead to amputation if untreated.
• From January 2019 to June 2022, the monthly percentage of fentanyl-related overdose deaths with xylazine detected increased 276% across 20 states and the District of Columbia, according to the CDC.

What Is Xylazine?

Xylazine (pronounced zye-luh-zeen) is a non-opioid veterinary sedative, analgesic, and muscle relaxant that is FDA-approved for use in large animals, including horses, cattle, and deer. It is sold under brand names including Rompun, Anased, Sedazine, and Chanazine.

It has no approved application in humans, and human trials conducted in the 1960s were discontinued because xylazine caused severe CNS depression and dangerously low blood pressure in humans at effective doses.

Xylazine is an alpha-2 adrenergic receptor agonist, meaning it works by stimulating receptors that reduce neurotransmitter release throughout the central nervous system. This mechanism produces sedation, pain relief, and muscle relaxation in animals. In humans exposed to illicit doses, it produces profound sedation, respiratory depression, and a dangerous drop in heart rate and blood pressure.

What Is Tranq Dope?

Tranq refers to xylazine when used alone as a street drug. Tranq dope refers specifically to the combination of xylazine with fentanyl or other opioids, which is by far the most common form in which people encounter xylazine.

When xylazine entered the illicit drug market in Puerto Rico in the early 2000s under the name anestesia de caballo (horse anesthetic), it was mixed with heroin. As fentanyl overtook heroin as the dominant opioid in the U.S. supply, xylazine migrated with it.

Why Is Xylazine Called the Zombie Drug?

The zombie drug label originates from two visible and disturbing effects of xylazine in people who use it regularly. The first is extreme, prolonged sedation that causes people to become immobile and unresponsive for hours, often in fixed, slumped positions.

The second is the progressive skin necrosis it causes, characterized by open, decaying wounds on the arms and legs that resemble tissue death and have been described in clinical reporting as rotting flesh. Both effects together produced the zombie drug name in media coverage and public discourse.

What Drug Class Is Xylazine?

Xylazine belongs to the alpha-2 adrenergic agonist drug class. It is structurally similar to clonidine, a human blood pressure medication, and shares pharmacological properties with phenothiazines and tricyclic antidepressants.

It is not a controlled substance under the federal Controlled Substances Act, though several states, including Pennsylvania, Florida, Ohio, West Virginia, and Delaware, have classified it as a scheduled substance under state law. In the United Kingdom, xylazine was made a Class C controlled drug in January 2025.

The absence of federal scheduling has historically limited law enforcement’s ability to prosecute xylazine trafficking and has contributed to its availability and spread.

Why Is Xylazine Added to Fentanyl?

Dealers add xylazine to fentanyl and heroin for three documented economic and pharmacological reasons. First, xylazine is cheap. It costs significantly less to produce or divert from veterinary sources than fentanyl, and mixing it into the supply reduces production cost per dose.

Second, xylazine extends the duration of the fentanyl high. Fentanyl’s effects are relatively brief compared to heroin. Xylazine-induced sedation lasts substantially longer, making the combined product feel more sustained and increasing its perceived value to buyers.

Third, xylazine accelerates dependence. Early research indicates that tranq dope may produce more intense withdrawal symptoms and stronger compulsive use patterns than fentanyl alone, which increases repeat purchases. Most people who encounter xylazine in their drug supply do not know it is present.

Effects of Xylazine on the Human Body

Immediate Effects

Xylazine produces the following acute effects in humans, particularly at the doses present in illicit drug supplies:

• Profound sedation that is deeper and longer-lasting than fentanyl alone, with episodes lasting hours rather than minutes
• Severe bradycardia (slowed heart rate) and hypotension (low blood pressure), creating cardiovascular stress independent of any opioid present
• Respiratory depression that, while not as acute as opioid-induced respiratory failure, can cause suffocation through airway compromise in a deeply sedated person
• Loss of postural control producing the same bent-over, immobile appearance as the fentanyl fold, but sustained for far longer periods
• Nystagmus (involuntary eye movement), a clinical sign specific to xylazine intoxication that distinguishes it from pure opioid presentation

The Xylazine Wounds

The most distinctive and clinically alarming physical consequence of regular xylazine use is severe skin and soft tissue damage. Xylazine causes ulcerations, abscesses, and areas of necrotic tissue death that spread progressively across the arms and legs, frequently appearing at locations distant from any injection site.

The mechanism is not fully understood, but xylazine’s alpha-2 agonist activity causes intense vasoconstriction that reduces blood flow to peripheral tissue, and the drug accumulates in fatty tissue, producing sustained local toxicity.

The wounds are clinically atypical: they spread faster than standard injection-site infections, they appear in people who snort or smoke the drug rather than inject it, and they do not respond well to standard wound care protocols.

Without treatment, these wounds can develop into deep tissue infections, osteomyelitis (bone infection), bacteremia, sepsis, and, in the most severe cases, limb amputation. In Philadelphia, the emergence of xylazine in the drug supply was directly followed by hospital systems reporting a sharp increase in severe skin and soft tissue infections requiring surgical intervention.

Any person with nonhealing skin ulcers or progressive wounds on their limbs who uses drugs should be evaluated clinically for xylazine exposure, regardless of their reported route of administration.

Xylazine vs. Fentanyl: Overdose Response Comparison

The table below illustrates why xylazine fundamentally changes overdose response and why everyone in contact with drug supply must understand the difference.

Feature	Fentanyl Overdose	Xylazine + Fentanyl Overdose
Primary mechanism	Opioid receptor-mediated respiratory depression	Opioid respiratory depression + alpha-2 CNS/cardiovascular depression
Responds to naloxone?	Yes	Partially: naloxone reverses fentanyl component only
Sedation duration after naloxone	Short (minutes to hours)	Extended: xylazine sedation continues after opioid reversal
Rescue breaths needed?	Sometimes	Yes — especially important given xylazine’s non-opioid respiratory effect
Skin wounds?	No	Yes — progressive necrotic wounds on limbs
How many naloxone doses needed?	1-2 typically	Multiple may be needed; 911 call essential regardless
Withdrawal syndrome	Opioid withdrawal only	Opioid withdrawal plus xylazine-specific withdrawal symptoms
Test strip detection?	Fentanyl test strips	Xylazine test strips (separate from fentanyl test strips)

The most critical clinical point in this table is the naloxone partial response row. A bystander who administers naloxone to someone who has used tranq dope may see partial improvement in breathing and conclude that naloxone has worked. The person may still be in life-threatening danger from the xylazine component. Calling 911 is not optional.

Does Xylazine Show Up on a Drug Test?

Standard drug testing panels do not screen for xylazine. A routine urine toxicology panel used in clinical, workplace, or legal settings will not detect xylazine. This is a significant clinical problem for emergency departments and treatment providers because a person presenting with xylazine-associated wounds or sedation may test negative for all substances on a standard panel while still being acutely intoxicated and dependent.

Specialized xylazine testing is available through forensic toxicology labs and is increasingly used in drug supply monitoring programs. As of March 2023, xylazine test strips became commercially available for harm reduction use, functioning similarly to fentanyl test strips. A positive xylazine test strip result means the substance is confirmed to contain xylazine, and the entire batch should be treated as hazardous.

Xylazine Withdrawal

Xylazine withdrawal is an emerging and poorly understood clinical challenge. Because standard opioid use disorder medications, including buprenorphine and methadone, do not address xylazine’s alpha-2 agonist mechanism, people physically dependent on tranq dope experience withdrawal symptoms that opioid-targeted medications do not fully relieve.

Xylazine-specific withdrawal symptoms documented in clinical literature include severe anxiety that can persist for weeks to months, intense agitation and restlessness, extreme irritability, and a general state of physical and psychological distress that is distinct from and may be more prolonged than opioid withdrawal alone.

The lack of an approved antidote or withdrawal management protocol makes xylazine dependence particularly difficult to treat and is a significant driver of relapse in people who want to stop using.

Treatment for Xylazine and Opioid Addiction

Xylazine exposure almost always occurs alongside fentanyl or other opioid dependence. Treatment must address the full substance use profile, and medically supervised detox is the essential starting point for anyone physically dependent on tranq dope or the opioids typically combined with it.

Medical Detox

Medical detox provides 24-hour nursing supervision and physician-directed care throughout withdrawal and stabilization. For people dependent on tranq dope, the clinical complexity of managing simultaneous opioid withdrawal and xylazine-related withdrawal symptoms, alongside the need to monitor and treat active skin wounds, makes medically supervised detox not just preferable but clinically necessary. Unsupported withdrawal from this combination carries serious risks that cannot be managed without medical oversight.

Medication-Assisted Treatment

Our medication-assisted treatment program uses FDA-approved medications including buprenorphine and naltrexone to address the opioid use disorder component of tranq dope dependence. While MAT does not directly reverse xylazine’s physiological effects, eliminating opioid dependence removes the primary mechanism driving continued tranq dope use and substantially reduces overdose risk.

Dual Diagnosis Treatment

Many people whose opioid use has escalated to include xylazine-contaminated supply are also managing untreated trauma, PTSD, anxiety, or depression. Our dual diagnosis program treats both the substance use disorder and co-occurring psychiatric conditions within the same integrated clinical framework. Untreated mental health conditions are consistently the strongest driver of relapse into a drug supply that may contain xylazine.

Residential Treatment

Our residential treatment program provides a fully supervised, structured environment where the earliest and most clinically vulnerable phase of opioid and xylazine recovery can proceed safely. Daily clinical programming runs seven days a week, with individual therapy, group therapy, and medical monitoring built into every day of treatment.

Contact our admissions team through the admissions process page for a confidential clinical assessment. Same-day assessments are available for individuals ready to begin treatment today.

Frequently Asked Questions

What is the drug xylazine?

Xylazine is an FDA-approved veterinary sedative with no approved human use that has entered the illicit drug supply as an adulterant mixed with fentanyl and heroin. It is an alpha-2 adrenergic receptor agonist, not an opioid, sold under veterinary brand names including Rompun. In the illicit market, it is called tranq, tranq dope, or the zombie drug. It causes profound sedation, cardiovascular depression, and progressive skin necrosis in humans and does not respond to naloxone.

What is tranq dope?

Tranq dope is the street name for the combination of xylazine with fentanyl or other opioids. The fentanyl component causes opioid-type respiratory depression that responds partially to naloxone. The xylazine component produces prolonged sedation, low heart rate, low blood pressure, and necrotic skin wounds that naloxone does not reverse. The Biden administration formally designated fentanyl combined with xylazine an emerging threat to the United States in April 2023.

Why is xylazine called the zombie drug?

Xylazine earned the zombie drug label from two clinical effects visible to observers. The first is extreme, prolonged immobility from sedation, in which users become unresponsive and fixed in slumped positions for hours. The second is the progressive necrotic skin wounds it causes on the arms and legs, characterized by open tissue death that spreads across the limbs. Both effects together produced the zombie drug description in media and public discourse.

Does naloxone work on xylazine?

No. Naloxone is an opioid antagonist and has no effect on xylazine’s alpha-2 adrenergic mechanism. However, because xylazine is almost always found alongside fentanyl, naloxone should always be administered in any suspected overdose to reverse the opioid component. After naloxone is given, rescue breaths should also be provided because xylazine-induced sedation may continue and compromise the airway even after the opioid effects are reversed. Calling 911 is essential regardless of naloxone response.

What does xylazine do to your body?

In humans, xylazine produces profound sedation lasting hours, severe drops in heart rate and blood pressure, respiratory depression, and loss of motor control. With repeated use it causes progressive necrotic wounds and abscesses on the limbs, appearing regardless of whether the drug was injected, snorted, or smoked. It also produces a withdrawal syndrome characterized by severe anxiety, agitation, and prolonged distress that standard opioid withdrawal medications do not fully address.

What drug class is xylazine?

Xylazine belongs to the alpha-2 adrenergic receptor agonist drug class, structurally similar to clonidine. It is not an opioid, not a benzodiazepine, and not a stimulant. It is not currently a federally controlled substance under the Controlled Substances Act, though multiple states have classified it as a Schedule. It is approved only for veterinary use and has never received FDA approval for any human application.

Does xylazine show up on a drug test?

Standard urine drug panels do not screen for xylazine. It requires specialized forensic toxicology testing to detect. Xylazine test strips, commercially available since March 2023, can detect xylazine in dissolved drug samples similarly to fentanyl test strips. A positive xylazine test result should be treated as confirmation that the entire drug supply is contaminated and dangerous.

References

1. Centers for Disease Control and Prevention. (2024). What you should know about xylazine. https://www.cdc.gov/overdose-prevention/about/what-you-should-know-about-xylazine.html
2. National Institute on Drug Abuse. (2025). Xylazine. https://nida.nih.gov/research-topics/xylazine
3. Drug Enforcement Administration. (2023). DEA reports widespread threat of fentanyl mixed with xylazine. https://www.dea.gov/alert/dea-reports-widespread-threat-fentanyl-mixed-xylazine
4. Kariisa, M., Patel, P., Smith, H., & Bitting, J. (2023). Notes from the field: Xylazine detection and involvement in drug overdose deaths — United States, January 2019–June 2022. MMWR Morbidity and Mortality Weekly Report, 72(26), 721-724.
5. Johnson, J., Pizzicato, L., Johnson, C., & Viner, K. (2021). Increasing presence of xylazine in heroin and/or fentanyl deaths, Philadelphia, Pennsylvania, 2010-2019. Injury Prevention, 27(4), 395-398.
6. Malayala, S. V., & Papudesi, B. N. (2023). Xylazine toxicity. In StatPearls. StatPearls Publishing.
7. The White House. (2023). Biden-Harris administration designates fentanyl combined with xylazine as an emerging threat to the United States.
8. Substance Abuse and Mental Health Services Administration. (2023). Key substance use and mental health indicators in the United States: Results from the 2022 national survey on drug use and health. https://www.samhsa.gov/data/