The Shape-Shifter: How Nitazenes Became America's Next Synthetic Opioid Wave

You don’t know you’ve taken it. That’s the part AmandaLynn Reese of Harm Reduction Ohio wants people to understand. The person who takes what they believe is fentanyl, or heroin, or even a pressed pill that looks like an oxycodone, doesn’t know that what they’re holding has been cut with a compound that is up to 40 times stronger than fentanyl and for which the antidote in the nasal spray in their pocket may not be enough.

“People are going to use drugs,” Reese said, describing her organization’s approach to the emerging threat of nitazenes—a class of synthetic opioids that barely appeared on the toxicology radar five years ago and now shows up in overdose deaths in 48 of 50 states. “Those are ways you can engage in your drug use to increase safety and reduce harm.”

The harm reduction framing matters because nitazenes have introduced a specific kind of psychological terror into the drug supply: you cannot know what you’re taking. You cannot dose with any precision. You cannot predict whether the naloxone in your possession will bring you back. The pharmacology of unknowing is itself a crisis—and it is spreading faster than any surveillance system has been able to track.

From 27 deaths to 409 in four years

In 2020, the CDC’s State Unintentional Drug Overdose Reporting System—SUDORS—confirmed 27 deaths involving nitazenes in the United States. By 2024, that number had reached 409. That’s a fifteenfold increase in four years, in a confirmed count that researchers believe substantially undercounts the true toll.

Alex Krotulski, director of the Center for Forensic Science Research and Education, put it bluntly to STAT News: nitazene deaths are underreported because the compounds are not part of standard toxicology panels. Most medical examiner labs test for fentanyl, heroin, cocaine, methamphetamine, benzodiazepines, and a handful of other scheduled substances. They do not test for nitazenes unless they specifically look—and most do not. Krotulski estimates that actual deaths since 2019 could reach 2,000.

The DEA’s seizure data tracks alongside this curve. In 2019, the agency recorded 43 positive laboratory tests for nitazenes. By 2024, that number had climbed to nearly 2,000. Over 8,000 nitazene reports have been recorded since 2019 across federal databases.

What the numbers don’t capture is the psychology of what’s actually happening in the drug supply. Nitazenes don’t typically arrive at a transaction as “nitazenes.” They arrive as something else. Frank Tarentino, who runs the DEA’s northeast regional operations, described the dealer logic to STAT News with uncomfortable clarity: “Dealers often mix nitazenes into other drugs to make them more powerful and addictive. It becomes a brand. Dealer’s choice becomes a deadly decision.”

A dealer who has a drug that’s more potent than anything available from competitors has a commercial advantage. The fact that a user doesn’t know what’s in the supply is not incidental—in the perverse economics of the illicit drug market, it’s a feature. More powerful drugs produce stronger dependence faster. The information asymmetry is intentional.

Ohio, Florida, Illinois—and the pattern moving west

Ohio accounts for over one-third of all positive national nitazene lab reports, and the death toll there has been devastating: 4 confirmed deaths in 2020, climbing to 90 in 2021, then to more than 200 across 2022–2024. The pattern in Ohio traces to an established trafficking network operating through eastern supply chains—a Bronx case unsealed in 2024 involves a defendant who transported more than 100,000 isotonitazene pills in buckets from Canada.

Florida has the second-highest confirmed reports. Illinois has emerged as a new epicenter, with more than 150 cases between 2024 and 2025 involving a compound called “metonitazepyne”—which is sold on the street under the name “orphine.” The naming matters, because orphine’s emergence is not accidental.

In July 2025, China placed the majority of known nitazenes under national control—a scheduling action that responded to years of pressure from U.S. authorities, DEA indictments of Chinese chemical suppliers, and a 2024-2025 interdiction surge by U.S. Customs that caught 41 nitazene consignments. The scheduling appeared to work: imports from mainland China dropped. But by the time the scheduling took effect, suppliers had already begun the workaround.

In July 2025, China placed the majority of known nitazenes under national control—a scheduling action that responded to years of pressure from U.S.

Jared Brown, a synthetic drug specialist at the UN Office on Drugs and Crime, described the dynamic to STAT News with a phrase that captures the entire arc of the synthetic opioid crisis: “Orphines have just enough of the molecule difference that it isn’t covered by the core definition that China has made.”

The pattern is identical to what happened after 2019, when China scheduled fentanyl analogs and suppliers in Mexico and India filled the resulting gap. You schedule the molecule; the chemists change the molecule. The substance is, in Brown’s framing, a shape-shifter—“always changing, evolving and adapting to their environment.”

Why naloxone isn’t enough

Every piece of public health messaging about opioid overdose in the last decade has emphasized naloxone: carry it, use it, give it to your friends. The message is correct, and it has saved hundreds of thousands of lives. It remains correct for nitazene overdose.

But the pharmacology of nitazenes introduces a new variable that the fentanyl era did not fully prepare the field for.

Naloxone works by binding to opioid receptors and blocking the opioid from activating them. The speed and completeness of reversal depend on two things: how much opioid is present, and how tightly the opioid has bound to the receptor. Fentanyl binds very tightly and dissociates slowly—which is one reason why fentanyl overdoses sometimes require multiple doses of naloxone to reverse. Nitazenes have similar or worse binding kinetics.

A 2026 review in the Journal of Medicinal Chemistry titled “The Nitazene Era: A Critical Turning Point in the Synthetic Opioid Crisis Beyond Fentanyl” described this precisely: the slow dissociation kinetics of nitazenes correlate with reduced naloxone sensitivity at the mu-opioid receptor. Cases of nitazene overdose have been documented requiring very high doses of naloxone, with deaths occurring despite administration. Prolonged toxicity—meaning the person revives initially, then crashes again hours later as the naloxone wears off and the nitazene reasserts—has been documented in clinical cases.

This creates a specific challenge for bystander overdose response. The standard protocol—administer naloxone, call 911, observe for several minutes, administer again if the person doesn’t revive—may not be sufficient for nitazene exposure. Extended monitoring, potentially in an emergency department, is likely necessary in ways that street-level response cannot provide.

What this means practically for people who use drugs is that carrying naloxone is still the right decision. It is better than not carrying it. But it is not the guarantee it may have functioned as during earlier phases of the fentanyl crisis. The compounds have become harder to reverse, and the people using them—unknowingly, in most cases—have no way of knowing to ask for more naloxone or to request extended monitoring.

The regulatory loop that won’t close

The nitazene scheduling history reveals something important about the structural failure of the current international drug control system: it is built to respond to what was, not to what’s coming.

When a compound gets scheduled—by China, by the DEA, by the WHO—the chemists who produce it already know what the scheduling covers. They have been watching the regulatory proceedings. The structural analog approach to scheduling (banning compounds that are “substantially similar” to scheduled substances) has been the DEA’s primary tool for keeping pace with novel synthetics since 2012. It has not worked. It has slowed individual compounds while accelerating the production of analogs designed to fall outside the definition.

The orphine compounds arriving in Illinois in 2025 and 2026 were not an accident. They were engineered responses to a scheduling action that the suppliers anticipated would come. The drug control architecture is, structurally, one step behind—and the step behind is now measured in deaths.

What would actually work is contested. Drug checking services—laboratory or point-of-care testing that can identify what’s actually in a sample—represent one approach. Several European countries have developed robust drug checking programs; the U.S. has not, and STREETS, the flagship new federal program for reaching people with addiction, explicitly prohibits harm reduction services that would include drug checking. Expanded naloxone access, formulations with longer half-lives, and novel opioid antagonists with extended efficacy are research priorities—but research timelines operate on a different schedule than the illicit drug supply.

Drug checking services—laboratory or point-of-care testing that can identify what’s actually in a sample—represent one approach.

In the meantime, the shape-shifter keeps shifting. Ohio is already tracking compounds that didn’t exist eighteen months ago. Florida’s toxicology labs are developing new testing protocols faster than the national surveillance system can absorb them. The confirmed death count will continue to rise, and the actual death count will be higher—because most labs still aren’t testing.

AmandaLynn Reese, doing street outreach in Columbus, knows this. The people she meets on rounds know it too, in a different way: they know the supply is unpredictable. They know something has changed. They don’t always know the name of what changed it.

The shape-shifter doesn’t introduce itself. That is its only reliable characteristic.

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The Rize newsroom tracks novel and emerging drug threats as part of its substance coverage mission. If you or someone you know needs help with opioid use disorder, find verified treatment options near you.