Medetomidine, a potent animal tranquilizer commonly used by veterinarians, is now rapidly becoming the preferred additive in fentanyl sold on the streets by drug trafficking groups in the United States.
According to public health alerts, the frequency of medetomidine, also known as “rhino tranquilizer,” appearing in illegal drug supplies in cities like New York, Philadelphia, and Chicago is higher than its counterpart xylazine.
Public health officials note that both medetomidine and xylazine are not opioid drugs, but these substances are often mixed with fentanyl to prolong its effects.
Medetomidine, known for its pain-relieving, heart rate-reducing, and sedative properties, is not approved for human use due to its potential to cause hallucinations. The drug is mainly produced in China.
The effects of medetomidine are so strong that it can induce a several-hour-long coma. While naloxone is typically used in medicine to reverse potentially fatal respiratory depression caused by opioids or their synthetic alternatives like fentanyl, medetomidine does not respond to naloxone.
The Philadelphia Department of Public Health states that medetomidine, not only 200 times more potent than xylazine, also leads to life-threatening withdrawal symptoms like increased heart rate and high blood pressure after its effects wear off.
In December 2025, New York State Health Commissioner Dr. James McDonald issued a health alert regarding medetomidine, warning of its impact on the central nervous system, potentially causing severe vomiting and high blood pressure that may require intensive care.
For families of fentanyl victims, medetomidine represents a deadly new development.
April Babcock, whose son died seven years ago from a fentanyl overdose, expressed concern about the addition of medetomidine to fentanyl, saying, “It feels like there’s a new synthetic drug emerging, and I have to learn how to pronounce it. It’s just crazy, and they all originate from China.”
The rise of medetomidine is also a worrying trend for law enforcement agencies.
Frank Tarentino, Deputy Director of Operations for the Drug Enforcement Administration (DEA) in the Northeast, stated that medetomidine is cheaper and more potent than xylazine, leading distributors to maximize profits by using it in drug synthesis.
Tarentino revealed that DEA labs across the country have seen a sharp rise in the use of medetomidine. In 2024, 72 samples of the animal tranquilizer were detected in seized drug samples, rising to 1,082 cases in 2025, with most medetomidine being mixed with fentanyl.
Medetomidine first appeared in illegal street drugs in Maryland in 2022 before spreading to states like Pennsylvania, Illinois, and California. By the end of 2024 and into 2025, multiple states, including West Virginia, Minnesota, and New York, issued health alerts regarding the drug.
In 2024, this drug became a significant threat.
In May 2024, the Chicago Emergency Medical Services reported 50 suspected opioid overdose calls in a single day – double the average daily calls, based on data from the Centers for Disease Control and Prevention (CDC). Hospitals noted drug users having a slow response to naloxone and slow heart rates.
A CDC investigation into the May 11-17, 2024, cluster of overdoses in Chicago found 12 confirmed, 26 probable, and 140 suspected medetomidine-related overdose cases, resulting in one death.
In Pennsylvania, the Philadelphia Department of Public Health reported that from May to November 2024, the proportion of illegal drugs containing medetomidine surged from 29% to 87%, while xylazine showed a similar decreasing trend.
In 2024, the Philadelphia Medical Examiner’s Office conducted a seven-month toxicology analysis, detecting medetomidine in the bodies of 46 individuals who died from overdose. Fentanyl was also found in their systems.
Dr. Stephen Loyd, Director of the West Virginia Office of Drug Control Policy, mentioned a similar surge in overdose calls related to fentanyl crisis two months ago in West Virginia, including 45 incidents involving medetomidine in the state capital of Charleston.
“While fentanyl is still the deadly factor there, medetomidine ‘makes things more complicated,'” Loyd said. Without proper medical intervention, a combination of medetomidine and fentanyl may be more lethal than xylazine, depending on the potency of the fentanyl.
However, as the practice of mixing these substances is relatively new, sufficient data is still lacking. The occurrence of low blood pressure and slowed heart rates from medetomidine may rebound after the drug’s effects wear off, leading to severe withdrawal symptoms.
Following her son’s death, Babcock founded the nonprofit “Lost Voices of Fentanyl,” with nearly 47,000 followers on Facebook.
She noted that medetomidine remains relatively unknown to parents so far. However, the emergence of a new drug replacing the more common xylazine doesn’t surprise her, as opioid drugs and their synthetic counterparts like fentanyl keep users addicted, seeking more.
According to CDC statistics, nearly 570,000 Americans died from drug overdoses from 2019 to 2024, with the majority from synthetic opioids.
President Donald Trump made solving the fentanyl crisis a hallmark issue, imposing tariffs related to fentanyl on China, Mexico, and Canada, declaring Mexican drug cartels as terrorist organizations.
In December 2025, Trump declared fentanyl a weapon of mass destruction, stating, “There’s no doubt that hostile forces are bringing fentanyl into America, partly because they want to kill Americans.”
Babcock finds it hard to understand why another potentially deadlier street drug like medetomidine mixed with fentanyl is allowed to take root in the country.
“They all started as legitimate pharmaceuticals in China,” she pointed out. “I know China has cracked down on fentanyl and its precursors, but what about other crazy synthetics?”
Tarentino said that medetomidine is “one hundred percent provided and supported by drug cartels” to maximize profits.
Explaining the tranquilizer’s availability in China and India due to its low price and high potency, Tarentino added that the drug began appearing in Mexico shortly after China’s fentanyl crackdown, synthesized there and trafficked into the US.
Similarly, other synthetic drugs like nitazenes, synthetic opioids, and medetomidine have started being illicitly produced in China and smuggled into the US.
“It’s being weaponized for profit, plain and simple,” Tarentino pointed out.
He expressed concerns that the emergence of medetomidine highlights the complexity of drug enforcement in an ever-evolving landscape.
On December 19, 2025, New York State issued a health alert about medetomidine. The New York State Health Department monitoring illegal substances found that 37% of opioid samples tested in 2025 contained medetomidine, up from just 4% in May 2024.
Tarentino revealed that in July 2025, nearly 15% of seized drug samples analyzed in the Northeast DEA labs contained medetomidine, with testing over the past 90 days showing medetomidine present in 32% of sampled drugs.
He noted that medetomidine mainly exists in powder form and is often mixed with other drugs, primarily fentanyl.
While the New York alert reported only a few cases hospitalized for withdrawal symptoms, Tarentino believes it’s too early to fully understand how the drug impacts overdose deaths in the state.
Although medications like medetomidine play a role in overdose deaths, Tarentino noted a general decline in overall deaths nationwide caused by synthetic opioids.
Preliminary data from the CDC shows a 25% decrease in drug overdose deaths (primarily due to fentanyl) from February 2024 to January 2025.
He attributed part of the decline to government pressure on fentanyl production and distribution.
A recent study on the decrease in opioid overdose deaths suggested that the disruption of the supply chain for fentanyl precursors from China had led to the decline. Over the past six months, the potency of illegal drugs, including fentanyl-laced pills passed off as Xanax and Adderall on the streets, has decreased.
Tarentino stated that in the past few years, only 30% or fewer of fentanyl-laced pills were deadly, compared to 70% previously.
Operating under “Operation Fentanyl Free America,” the DEA aims to combat the fentanyl supply chain and reduce its circulation in the US.
“We’re working to dismantle the entire illegal supply chain and hold those responsible accountable. Our primary mission is safeguarding American communities and citizens,” he said.