Responding to the Emerging Threat of Xylazine

On April 24, 2026, harm reduction program directors across the country received an email from SAMHSA that began like many routine funding communications — until they got to the part that wasn’t routine. The “Dear Colleague” letter, six pages, declared that federal grant funds could no longer be used to purchase fentanyl test strips. Or xylazine test strips. Or test strips for medetomidine, the veterinary sedative that had quietly colonized the illicit drug supply in cities from Philadelphia to Pittsburgh to Knoxville, and that would, by June, appear in 91 percent of fentanyl-positive samples tested in Philadelphia.

The policy change was precise about who it did and didn’t apply to. Law enforcement could still buy test strips. Medical workers in the regular course of their professional duties could still buy test strips. Public health officials doing institutional surveillance could still buy test strips. The one group that could not — the group most likely to be standing in front of someone holding a syringe who needed to know right now what was in it — was the people running syringe service programs and community harm reduction outreach. The only people whose entire job was keeping drug users alive long enough to reach treatment.

This is not an abstract policy dispute. Medetomidine, the drug the federal government just decided not to test for, causes a withdrawal syndrome so severe that emergency departments are reporting patients who require hospital admission simply to survive stopping it. Unlike xylazine, it cannot be reversed by naloxone. It also cannot be detected without a test strip, because it looks and acts like fentanyl until withdrawal hits — and then it doesn’t act like anything the medical system has ever seen at scale.

The question this policy raises is not whether the Trump administration supports harm reduction. It clearly does not, and it has never claimed to. The question is whether this particular restriction makes sense on its own terms — and the answer, according to the pharmacists, physicians, epidemiologists, and county health officials who have been saying so in public since April, is that it does not.

The drug moved faster than the policy did

Medetomidine is an alpha-2 adrenergic agonist used in veterinary medicine to sedate cats and dogs before surgery. It first appeared in Philadelphia’s drug supply in meaningful concentrations around late 2023. By April 2024, the Center for Forensic Science Research and Education was detecting it in the majority of fentanyl samples it tested in the city. By early 2026, that number had climbed to 91 percent, according to Labcorp’s June 2026 Drug Trends Report — a figure that made Philadelphia’s drug market essentially medetomidine-fentanyl market, xylazine mostly gone, the new adulterant so entrenched it had become the baseline.

The national picture is following the same arc, just a few months behind. A study published in the journal Tandfonline examining the Great Lakes states documented xylazine declining as medetomidine rises across that entire region. In Tennessee, crime labs began detecting medetomidine in September 2025. The CDC and the White House Office of National Drug Control Policy issued a joint national alert on April 2, 2026 — three weeks before SAMHSA prohibited the test strips that would allow frontline workers to detect it.

The alert was appropriately alarming. Medetomidine is roughly two to four times more potent than xylazine in its sedative effects. Like xylazine, it is an alpha-2 agonist, meaning it doesn’t respond to naloxone — you can administer all the naloxone you want and the opioid component of the overdose will reverse, but the person will remain profoundly sedated from the medetomidine and may stop breathing anyway. Unlike xylazine, which causes severe skin wounds but has a relatively manageable withdrawal, medetomidine dependence — which can develop rapidly in people using fentanyl-medetomidine daily — produces a withdrawal that is, in the words of the multicenter Philadelphia study published in PubMed in April 2026, potentially life-threatening and requiring hospital management.

Medetomidine is roughly two to four times more potent than xylazine in its sedative effects.

Emergency departments in Philadelphia and Pittsburgh began reporting cases in early 2026: people seeking treatment for fentanyl use disorder who went into withdrawal not from opioids but from medetomidine, a drug their physicians had never managed at scale in humans, a drug with no FDA-approved treatment protocol, a drug that for most of American medicine doesn’t yet exist as a human disease category.

What test strips actually do — and what defunding them actually costs

A fentanyl test strip costs between $0.50 and $1.50. It takes about two minutes to use. A person using drugs dissolves a small amount of their supply in water and dips the strip; a positive result means fentanyl (or an adulterant with similar chemistry, including medetomidine) is present. The test is not perfect — it doesn’t tell you how much is present, or in what concentration — but in the context of an illicit drug supply contaminated with unpredictable adulterants, imperfect information is substantially better than no information.

For xylazine and medetomidine specifically, strips designed to detect them function as critical early warning tools. A person who knows their fentanyl is adulterated with medetomidine can make a different choice: use less, use with someone else present, seek a naloxone kit designed for stimulant overdoses (which can keep a person’s airway open longer), or decide to seek medical supervision. These are the kinds of informed decisions that harm reduction is built to enable.

The American Society of Health-System Pharmacists, which represents pharmacists in hospital and clinical settings, released a formal statement on April 30 opposing the SAMHSA restrictions. The statement was direct: the restrictions undermine a proven life-saving intervention at the worst possible time, precisely when the drug supply is becoming more dangerous, not less. The organization cited the approximately 19 percent national decline in overdose deaths since their August 2023 peak and the role of expanded harm reduction services in that decline.

Dr. Nab Dasgupta, an epidemiologist at Columbia University’s Mailman School of Public Health who has testified before Congress on the failures of drug scheduling policy, has written that what makes harm reduction politically vulnerable is that it operates at the margins of legality in a legal culture that punishes drug use. The people it serves — people who use drugs, people in active addiction — are not a constituency that calls their representatives. They are exactly the population least able to defend the programs designed to keep them alive.

On June 11, 2026 — seven weeks after the test strip ban — SAMHSA announced $40 million in new funding opportunities under the President’s Great American Recovery Initiative. The programs include $9.2 million for Behavioral Health and Community Safety Partnerships and funding to strengthen the behavioral health workforce. The announcement described the initiative as “preventing addiction” and addressing “mental illness and suicide.”

There is no contradiction in the administration’s framing. The policy defines harm reduction — distributing test strips to people who use drugs in the community — as “facilitating illegal drug use.” It defines recovery programs as evidence-based. Those two categories are treated as mutually exclusive. The people running syringe service programs, who have watched overdose deaths fall as test strip distribution expanded, find this distinction difficult to understand.

A two-tiered system built on a legal fiction

The Dear Colleague letter does not ban test strips. It bans the use of federal grant funds to purchase them for public distribution. The distinction matters — and it is also a fiction.

Harm reduction organizations that distributed test strips under SAMHSA grants do not have alternative funding sources for the same scale of distribution. The infrastructure — trained staff, community relationships, storage, distribution routes, trust built over years — runs on the grants. When the grants can no longer pay for test strips, organizations don’t find another funder and carry on. They make do, which means fewer strips, less distribution, less reach into the communities where the drug supply is most dangerous.

The infrastructure — trained staff, community relationships, storage, distribution routes, trust built over years — runs on the grants.

Law enforcement can still buy strips. Medical workers can still buy strips. County health departments, when acting in their professional capacity, can still buy strips. This is the two-tier system: the people with institutional authority and likely lower direct exposure to the worst of the drug supply retain access to the detection technology. The people physically present at the point of use, in the encampments and doorways and apartments where medetomidine-fentanyl is being consumed, cannot use federal funds to provide the one tool that might give the person in front of them actionable information about what they’re about to inject.

The National Association of Counties documented the practical consequences in a May 2026 analysis: counties that depend on SAMHSA grant funding for behavioral health services — a substantial portion of American counties, particularly rural ones — cannot absorb the test strip costs out of discretionary budgets that are already stretched. The restriction hits hardest in the places with the least capacity to absorb it.

The overdose decline and the thing that could end it

The approximately 19 percent decline in overdose deaths since August 2023 is real, and it represents tens of thousands of lives. It is the most significant sustained decline in overdose mortality in the history of the opioid crisis, and public health researchers have pointed to multiple contributing factors: expanded naloxone access, broader fentanyl test strip distribution, increased medication-assisted treatment availability, and naloxone co-prescribing requirements in many states.

The medetomidine complication does not fit neatly into any of those buckets. Naloxone doesn’t fully reverse it. Test strips — now defunded for community distribution — would detect it. Medication-assisted treatment doesn’t address the medetomidine withdrawal component. The medical system is not yet equipped to manage it at scale.

What this means for the overdose decline is uncertain. Medetomidine spread rapidly enough to reach 91 percent of Philadelphia’s fentanyl supply in under two years. If that trajectory holds nationally, the conditions that drove the 19 percent decline — including test strip distribution — will be operating against a drug supply that is materially more dangerous than the one they were designed for, with at least one of the key tools defunded.

The people tracking this trajectory most closely are the ones in the field. The harm reduction workers who run syringe service programs, who have held the federal Dear Colleague letter and looked at their supply budget and made the math work out somehow, are not confused about what is happening. They have watched the drug supply evolve for years, and they know what medetomidine looks like when it arrives in a community that isn’t ready for it. It looks like people going into withdrawal that the emergency department doesn’t know how to treat. It looks like deaths attributed to fentanyl that were actually medetomidine-fentanyl, which matters for how you respond to the next one.

It looks like something you would want a test strip for.

The strip that, as of April 24, you can no longer buy with federal money — at least if your job is keeping people alive at the point of use rather than in a hospital or a courtroom. That distinction, in the specific geography of this overdose crisis, is the one that will count.