Medetomidine: The New Veterinary Sedative Ravaging Philadelphia

Philadelphia might be ground zero for a new and dangerous phase of the nation’s drug crisis as medetomidine, an extremely potent veterinary sedative, rapidly replaces xylazine in the city’s fentanyl supply. Unlike xylazine, or tranq, a large-animal tranquilizer infamous for causing severe tissue damage in users, medetomidine’s most devastating effects stem from extreme dependence and subsequent withdrawal. 

“Our ICUs have been overwhelmed,” emergency physician Daniel del Portal told the New York Times, with people ravaged by withdrawal that can leave them mute, unaware and seemingly unable to control bodily functions, with blood pressure so high that it could cause brain damage. The Center for Forensic Science Research and Education has identified the substance – which can be 200 times more potent than xylazine – in 91 percent of Philadelphia’s tested drug supply. 

Now, it’s making its way to other cities across the east and midwestern parts of the country. Medetomidine causes users to black out almost instantaneously, and life-threatening withdrawal symptoms – including dangerously fast heart rates, sky-high blood pressure, tremors, delirium, and uncontrollable vomiting – kick in if it’s not used every few hours. 

Knowing this, many users are terrified to seek help. Some describe waiting for hours with worsening withdrawal, as patients with serious physical injuries are treated first, before having to leave and seek more medetomidine to end their agony, or remain alive long enough to get help. It’s a choice that Joseph, six months sober, remembers having to make. Facing convulsions, vomiting, delirium and hallucinations in the home of a friend who had been attempting to help him get sober, he asked for a few dollars. “I have to get right,” he said. The quick hit he purchased put off his withdrawal just long enough to get him to the hospital’s doors. 

Public health officials trace the drug’s arrival in Philly to late April 2024, when ERs were flooded with more than a hundred opioid overdose patients who, though treated with overdose reversal medication, did not resume consciousness as their breathing restarted – as is typical for such cases. Instead, they remained sedated for as long as 12 hours, with very slow heartbeats. The picture became clearer by that fall, and the danger of medetomidine continues to show in Philly hospitals. 

From January to September 2025 alone, the city recorded 7,252 ER visits for withdrawal, compared to 2,787 for all of 2023. To help patients stabilize, doctors now administer intravenous dexmedetomidine, a safer human relative of the drug.

But medetomidine withdrawal is not a recognized diagnosis that requires extended hospitalization, limiting reimbursement by insurers. As weather gets colder, sedated users outside are at increasing risk – but doctors fear they don’t have capacity for what Dr. Teixeira da Silva of the city’s health department called “a public health crisis of prolonged sedation.”