Nobody Had a Name for What Dominic Cipriano's Body Was Doing. Doctors Took Nine Months to Write One Down.

In the spring of 2024, according to the Philadelphia Inquirer’s reporting, Dominic Cipriano started shaking and could not stop. It was not the kind of shaking he knew. He rocked side to side on the Kensington sidewalk, sweating, vomiting, jerking, and then the street went dark. He had blacked out. By the Inquirer’s count he went on to have more than a dozen suspected seizures that year. His own question, as the Inquirer’s story relays it, was the one every doctor in the city was about to ask: what the hell is that from?

Medetomidine didn’t just make the supply deadlier. It made quitting dangerous in a new way, and the people going through it learned that first.

The answer, it turned out, was a sedative made for dogs, one more entry in the novel and emerging substances we keep having to learn the hard way. It had begun appearing in Philadelphia’s fentanyl supply, and when people who had been using it stopped, their bodies did something no withdrawal chart described. If you have ever gone through opioid withdrawal, you know the shape of it: the aches, the sweats, the gut, the misery that feels like it will kill you and almost never does. This was something else. Cipriano’s half-sister, Diamond Stahl, a certified recovery specialist at Penn Medicine who has been in recovery for three years, went looking for him on the streets and texted him the only thing she could think of: please don’t die.

The warning didn’t come from a lab; it came from bodies

For a stretch of 2024, the people who knew about medetomidine were the people who were taking it without being told. It rode inside fentanyl, the way xylazine had before it, and the people taking it were not choosing it by name. The CDC reports that 98% of the medetomidine-positive samples it tracks also contained fentanyl. By the time hospitals could confirm what they were looking at, the drug was already widespread: the Inquirer reported that by early 2025 it was in roughly 70% of the illicit opioid samples tested in Philadelphia, and that it turned up in about 15% of fatal overdoses between May 2024 and May 2025.

Here is the part that matters if you have been on the receiving end. Medetomidine is a close cousin of a drug hospitals already use, called dexmedetomidine, which goes by the brand name Precedex. It is an ICU sedative that works by turning down the body’s adrenaline alarm system. Pull it away from a body that has gotten used to it and the alarm doesn’t just ring. It screams. Heart rate climbs, blood pressure spikes, the hands shake, and the mind goes somewhere it does not want to go. The CDC says symptoms can begin within hours of the last use and peak 18 to 36 hours later, and they include a racing heart over 100 beats a minute, severe high blood pressure, swings in alertness, tremor, chest pain and vomiting that will not quit.

Here is our read of what that does to the head, and it is an inference, not a study finding, so test it against your own history. If every earlier attempt to stop taught you that withdrawal was miserable and survivable, then you learned to trust your read of your own body. A withdrawal that behaves differently breaks that trust. You stop being afraid of the symptoms you know and start being afraid of the ones you don’t, and fear of the unknown is exactly the kind of pressure that sends a person back to the one thing that quiets the shaking. If that has been you, it was not a character flaw. It was a reasonable response to a body that had started giving you bad information.

If every earlier attempt to stop taught you that withdrawal was miserable and survivable, then you learned to trust your read of your own body.

We have written before about how a ban on one substance can leave a withdrawal gap with no plan behind it, and about what recovery looks like from the inside. This story belongs on that shelf. The Inquirer story tracks Cipriano through all of this, the seizures, the hospital, the Precedex drip at Penn Presbyterian, the symptoms that lingered even after he was treated. What it does not describe is a clean path. It describes a man whose supply changed under him, whose own family was texting him not to die, and who showed up to a medical system that had not yet decided what to call his condition. He did, in the end, enter an inpatient program. His own summary of it: “I made it. I picked myself up.”

Doctors named it in the ICU, 165 patients at a time

If you want the clinical version, it exists, and it is stark. In May 2025, doctors at three Philadelphia health systems published a report in the CDC’s Morbidity and Mortality Weekly Report describing 165 patients admitted between September 2024 and January 2025 with what the authors, led by Dr. Samantha Huo, called suspected medetomidine withdrawal syndrome. Of those 165, 91% needed intensive care and 24% had to be put on a breathing tube. The typical patient was 38 years old. The median systolic blood pressure, the top number, was 195. The median heart rate was 145.

The finding that changed practice was a negative one. The standard drugs used to ease opioid withdrawal were not enough, and the report says patients’ symptoms were resistant to increasing doses of them. What worked, for 83% of the patients, was an infusion of dexmedetomidine, the same cousin of the street drug, given in a hospital where staff could watch the heart. In plain terms: the thing the body was missing turned out to be the thing the hospital had in its pharmacy. Three patients developed posterior reversible encephalopathy syndrome, a dangerous brain condition that blood-pressure spikes can trigger, and at one health system 39 of the 62 patients tested had lab results consistent with a type of heart attack known as NSTEMI.

It is important to be exact about what that report is and is not. It is a “Notes from the Field” case series, one city, a few months, no comparison group. It tells clinicians what they will see; it does not tell anyone how often it happens per person who uses. Penn doctors quoted by the Inquirer were open about the guesswork, saying they were “really throwing the kitchen sink” at it: opioid medications like methadone and buprenorphine to start, clonidine to bring blood pressure down, ketamine infusions in some cases, Precedex where they could get it. At Jefferson Methodist, the Inquirer reported, clinicians began giving Precedex outside the ICU because there were not enough ICU beds to go around.

The scale shows up in the volume. The Inquirer reported emergency room visits for withdrawal in the city rising from roughly 800 to nearly 2,400 in a year. And the thing has not stayed in Philadelphia. In April 2026 the CDC and the White House drug policy office took the unusual step of issuing a national health advisory, which reports that federal seizure records of medetomidine rose from 247 in 2023 to 8,233 in 2025, and that 98% of the samples that contained it also contained fentanyl.

That last number is the one to hold onto if you use. Because fentanyl is in almost everything that has medetomidine in it, an overdose is still, first, an opioid overdose. Naloxone, the reversal medication, still works on the part of it that is opioid, and the CDC’s guidance is to give it and repeat it every two to three minutes if breathing does not return. The Inquirer reported that naloxone does not reverse the sedative itself, so a person can come back to breathing and still be hard to rouse. Call for help anyway; the CDC says to consider medetomidine when sedation continues after adequate naloxone.

The Inquirer reported that naloxone does not reverse the sedative itself, so a person can come back to breathing and still be hard to rouse.

None of this is new as a pattern, only as a chemistry. The people closest to a harm learn the rules long before the paperwork does, and for a while the gap between knowing and acting is paid for in bodies.

In 1988, as HIV moved through people who inject drugs, Congress, pushed by Senator Jesse Helms, banned federal money for syringe exchanges. The evidence moved faster than the law. In 1995 an Institute of Medicine panel recommended lifting the ban and a CDC review confirmed that exchanges reduced HIV infection. In 1997 Health Secretary Donna Shalala endorsed the science, and the administration kept the ban anyway. Congress did not lift it until 2009, and reinstated it in 2011. Zoe Hudson, of the Open Society Foundations, called the reinstatement “a lethal blow to HIV programs that are proven to work.” The people who inject were never confused about whether a clean syringe worked. They had it figured out in the first year. It took the government more than two decades to stop standing in the way.

Medetomidine is that story on a shorter clock. By the Inquirer’s account, roughly nine months passed between Philadelphia doctors first coordinating on the pattern and official treatment guidance arriving in June 2025. Nine months is fast, by the standards of medicine. It is a lifetime if you are the one on the sidewalk.

What a clinic can do this week, and what only a hospital can

If you work in a treatment program, a detox, an outpatient clinic or a harm reduction van, the instruction from the people who have lived this is simple: stop assuming that a person who tells you they are going through withdrawal is going through the withdrawal you already know how to manage.

Start with intake. Ask the question nobody used to ask: have you been told your supply has a sedative in it, and how long since your last use? The CDC says to consider medetomidine when a person has unexplained prolonged sedation, or atypical and severe withdrawal. Write down a numeric threshold with your local emergency department for sending someone out, for example the racing heart and severe blood pressure the CDC describes, so that nobody is making that call alone at 2 a.m. Put the poison control number, 1-800-222-1222, which the CDC lists for clinicians, where your night staff will see it. Ask your lab whether your toxicology panel can detect medetomidine at all; the CDC’s advisory asks laboratories to help monitor it, and you cannot treat what your lab cannot see.

Then be honest about the limits of your own building. The dexmedetomidine infusion that worked in Philadelphia is a hospital tool, given where someone can watch a heart monitor. No outpatient clinic should try to copy it. Clonidine and standard opioid treatment may help a milder case, and whether a given state or payer covers a given step is something to settle with your medical director before the 2 a.m. call, not during it. The honest provider move this week is to know exactly where your threshold for “this belongs in a hospital” sits, and to have the phone number of the hospital that will take the transfer.

The door that is still open

If you are someone who uses, and your last withdrawal did not feel like the ones before it, here are things that are still yours tonight. Naloxone is still available, and it is still the first move when breathing stops. You can ask for it at a pharmacy or a harm reduction program, and you can carry two. The CDC advises avoiding mixing sedating substances and notes that test strips can miss things, which is the kind of caveat you earned the right to hear in plain words. And if you are shaking in a way that scares you, go to an emergency room and say the word “medetomidine.” It is a real word now, in real charts, and a growing number of staff know what to do when they hear it.

Naloxone is still available, and it is still the first move when breathing stops.

Dominic Cipriano did not need anyone to explain that his body had changed the rules. He needed a bed, a nurse who recognized the pattern, and a half-sister who kept texting. A system can build the first two. The third is something you can be for someone this week.