Ground Zero
Kensington — a neighborhood in Philadelphia long devastated by opioid addiction — became the epicenter of a new crisis when xylazine, a large-animal veterinary tranquilizer, began showing up in the street fentanyl supply. Known on the street as "tranq," the drug amplified overdose risks and introduced gruesome, hard-to-heal wounds that overwhelmed local healthcare systems.
Now xylazine is being replaced by an even more potent veterinary sedative, medetomidine — nicknamed "rhino tranq" — creating what doctors are calling a full-scale withdrawal crisis in Philadelphia's intensive care units.
What Is Xylazine?
Xylazine is an alpha-2-adrenergic agonist used as a sedative and analgesic by veterinarians — primarily in large animals like horses and cattle. It is not approved for human use by the FDA.
Drug traffickers began adding xylazine to street fentanyl as a cheap "filler" that extended users' short-lived high and increased dealers' margins. Suppliers could purchase it for as little as $6 per kilogram online. Within a few years, it had fundamentally changed the street drug supply in Kensington.
"Opioid traffickers began adding the tranquilizer to fentanyl as a 'filler' that extended users' short-lived high — and increased dealers' profits."
— U.S. Drug Enforcement AdministrationWhy It's Dangerous
- Slows breathing, heart rate, and blood pressure to life-threatening levels
- Naloxone (Narcan) does not reverse xylazine's effects — only the opioid component
- Causes severe, persistent skin wounds and deep tissue ulcers
- Wounds can appear far from injection sites and expose bone
- Carries significant withdrawal risk with heavy use
Who Is Affected
- People who use drugs in Kensington often don't know xylazine is in their supply
- Study sample: 62% white, 26% Black, 67% male, 83% unhoused
- Wound patients frequently avoid hospitals due to stigma and withdrawal fears
- Amputations in Philly doubled among people addicted to opioids in recent years
Important for bystanders: Even though naloxone won't reverse xylazine, experts still recommend giving it during suspected overdoses — because fentanyl is almost always present alongside xylazine. Always administer naloxone and call 911.
How We Got Here
2019–2020
Xylazine Emerges in Philadelphia
Philadelphia becomes the first major U.S. city where xylazine is detected widely in the fentanyl supply. Harm reduction workers begin noting unusual, persistent skin wounds.
2022–2023
Crisis Reaches Scale
By late 2023, xylazine is found in over 90% of street fentanyl samples in Philadelphia. Hospitals report a surge in severe soft tissue infections. Amputations double. Kensington becomes ground zero of national media coverage.
2023
National Alert Issued
The Biden administration issues a national warning about xylazine in the fentanyl supply. Xylazine test strips become commercially available in March 2023, distributed by Philadelphia health programs.
2024
Xylazine Restricted; Medetomidine Arrives
Pennsylvania makes xylazine a controlled substance to limit dealer access. But cartels respond by switching to medetomidine. The last weekend of April 2024, emergency departments are overrun with 100+ unusual overdose cases — patients who received naloxone and resumed breathing, but did not wake up, remaining deeply sedated for up to 12 hours.
Late 2024 – 2025
The Withdrawal Crisis
Medetomidine dependence creates catastrophic withdrawal — racing heart rates of 170+ BPM, dangerous blood pressure swings, encephalopathy, and cases of suspected brain damage. ICUs are overwhelmed. By early 2025, medetomidine appears in roughly 91% of tested fentanyl samples. Between 2024 and 2025, skin infections from xylazine drop by more than half — but are replaced by a new crisis of severe withdrawal.
Health Effects of Xylazine
| Effect | What Happens | Clinical Significance |
|---|---|---|
| Respiratory depression | Dramatically slows breathing | Life-threatening; occurs alongside fentanyl's own respiratory effects |
| Cardiovascular | Low heart rate, low blood pressure | Can cause cardiac arrest; not reversed by naloxone |
| Skin wounds | Deep ulcers, abscesses, necrotic tissue | Appear all over body (not only at injection sites); can expose bone; slow to heal |
| Sedation | Deep, prolonged unconsciousness | Users incapacitated outdoors; vulnerability to violence and exposure |
| Withdrawal | Anxiety, irritability, elevated heart rate and blood pressure | Deters hospital visits; requires dedicated clinical management |
The Wound Crisis
Perhaps xylazine's most visible impact is the severe, necrotic skin wounds it causes. Unlike typical injection-site infections, xylazine wounds appear anywhere on the body and worsen rapidly. Many people experiencing these wounds avoid hospital treatment due to stigma and fear of withdrawal — leading to infection, bone exposure, and in many cases, amputation.
Wound care vans and clinics, including those run by Prevention Point Philadelphia and Kensington Hospital, now operate throughout the week to serve people who cannot or will not access traditional healthcare settings.
The New Crisis: Medetomidine
⚠ Critical Update for 2025
Xylazine is rapidly being replaced by medetomidine — a veterinary sedative 100–200 times more potent — in Philadelphia's street drug supply. As of early 2025, it is present in the overwhelming majority of tested fentanyl samples in Kensington.
Medetomidine, also called "rhino tranq," has been used by veterinarians for 30 years. When mixed into street fentanyl, it causes far more severe sedation than xylazine — users can remain unconscious for up to 12 hours after receiving naloxone. Its withdrawal syndrome has overwhelmed ICUs across Philadelphia.
Medetomidine Withdrawal Symptoms
- Uncontrollable tremors and shaking
- Heart rate surging to 170+ BPM
- Dangerous blood pressure swings
- Encephalopathy (brain dysfunction)
- Patients becoming mute, unresponsive
- Mimics heart attack symptoms
- 77.5% of hospitalized patients required ICU care (2024–25 study)
Why Cartels Switched
- Pennsylvania restricted xylazine purchases in 2024
- Medetomidine is cheaply available and poorly regulated
- Drug policy experts warn: crackdowns push traffickers to find alternative, often more dangerous, adulterants
- Medetomidine leaves the body quickly — hard to detect in standard drug tests
- No medical billing code yet exists for medetomidine withdrawal — limiting hospital reimbursement
"Our ICUs have been overwhelmed. Doctors, emergency workers and outreach teams now refer to 'the withdrawal crisis.'"
— Dr. Daniel del Portal, Temple Health Emergency PhysicianIn a six-month stretch in 2024–2025, a special critical care ambulance transported 255 patients on a two-mile trip from Temple's Kensington satellite to its main hospital — at a cost projected to reach $2 million for transport alone by year's end.
Resources in Kensington
Multiple organizations provide wound care, harm reduction supplies, overdose prevention education, and social services to people who use drugs in the Kensington area. Below are key local resources.
Prevention Point Philadelphia
Wound Care Clinic at 2913 Kensington Ave. Operates Mon, Wed, Fri 11am–3pm. Supplies, testing strips, naloxone.
ppponline.org ↗Substance Use Philly
Official Philadelphia Dept. of Public Health resource on xylazine, medetomidine, wound care, and treatment guidance.
substanceusephilly.com ↗The Everywhere Project
Weekend harm reduction outreach in Kensington. Wound care, naloxone, and community support. 300+ people served each weekend.
Learn more ↗Kensington Hospital Wound Care Van
Mobile wound care at Rock Ministries, 2755 Kensington Ave. Tuesdays 9am–4pm.
Details ↗Catholic Workers Clinic
1813 Hagert St. Wed 4:30–6:30pm, Thu 11:30am–1:30pm. Wound care and supplies.
Details ↗NIDA Xylazine Info
National Institute on Drug Abuse resource page on xylazine, research updates, and overdose guidance.
nida.nih.gov ↗Crisis line: If you or someone you know needs immediate help with substance use, call SAMHSA's National Helpline: 1-800-662-4357 (free, confidential, 24/7). For overdose emergencies, call 911 — Pennsylvania's Good Samaritan Law provides legal protections for those who call.