Tasmania's First U-Class Opioid Death Is a Warning About a Supply Nobody Can See

There is a particular kind of overdose notice that public health departments dread writing, the one that says: we do not know what this was, we know it was new, and we think the person who died did not know either. On October 6, Tasmania’s health department wrote one. ABC News reported that a person died after taking a substance suspected to have been laced with a strong opioid, and that it was the first known detection in the state of a novel synthetic opioid from the so-called U-class.

A drug you can’t see coming is a drug you can’t plan around, and that is the whole problem with this family of compounds.

Dr Dinesh Arya, quoted in the health department’s alert, said “U-class opioids are not regularly detected in Australia.” Amanda Roxburgh of the Burnet Institute, an Australian public health research group, told ABC the window between taking it and overdosing is so short that people can “overdose and die within minutes.” The department urged health professionals to keep naloxone on hand. ABC also reported that the person who died may not have known what they were taking.

What “U-class” means, in plain words

Start with what these drugs are. They are synthetic opioids, made in a lab rather than grown or extracted from a plant, that act on the same receptors in the brain as heroin, fentanyl and prescription painkillers. “U-class” refers to a family named for a laboratory compound, U-47700, that first drew attention a decade ago. It sits alongside the nitazenes, a related group of lab-made opioids that researchers describe as similar to fentanyl, with some variants up to 50 times more potent and acting within about two minutes.

The potency is only half the problem. The other half is the surprise. A study of 32 Australian emergency department presentations, published in Drug and Alcohol Review, found that 84% of the people who ended up in hospital were unaware they had taken a nitazene; they believed they had taken something else. Nearly all of them, 97%, had other drugs on board, mainly methamphetamine. Thirteen patients, about 41%, needed intensive care.

That study has limits you should know about: it is 32 patients across two surveillance systems, so it describes a pattern in people who got to a hospital, not the risk to everyone who uses. It also carries one genuinely good piece of news. Naloxone, the overdose reversal medication, was given in 72% of the presentations at a median dose of 400 micrograms by IV in the first hour, and the authors concluded that standard dosing appeared effective in most cases. The thing everyone is told to carry still works on these.

The surveillance gap is the story

Here is why a single death in a single state deserves attention. A 2025 scoping review by Emmanuel Mammoliti, Suzanne Nielsen and Roxburgh counted what Australia could document: 22 deaths involving fentanyl analogues between 2013 and 2021, 12 involving U-47700 between 2016 and 2021, and 33 nitazene deaths, 24 of them in Victoria. The Australian Federal Police made 47 nitazene seizures from July 2023. And, the review noted, nitazene detections had turned up in every Australian state except Tasmania.

Until now.

The authors are candid about what they could not see. Their data on deaths is incomplete because coroners’ investigations take time. Publication lags mean trends are visible late. Nitazenes can occur in low concentrations that standard screens miss, and toxicology testing varies from one jurisdiction to the next. The review also names the gap that matters most to the person holding the pill or the powder: researchers do not really know how many people are taking these drugs on purpose and how many are being handed them inside something else. Roxburgh put the conclusion bluntly in Burnet’s statement: “Now is the time to strengthen how we respond on the front line.”

Roxburgh put the conclusion bluntly in Burnet’s statement: “Now is the time to strengthen how we respond on the front line.”

The review’s recommendations are specific. It calls for expanding drug checking, the service that lets someone have a substance tested before they take it, beyond the three jurisdictions that currently offer it (ACT, Victoria and New South Wales), and for expanding take-home naloxone in entertainment settings and to everyone who uses drugs. Tasmania is not among the three.

We have been told this was handled before

If any of this sounds like the same lesson wearing a new name, that is because it is. In November 2016, the DEA placed U-47700 into Schedule I, effective November 14, on an emergency basis, citing at least 46 confirmed deaths, 31 of them in New York and 10 in North Carolina. The drug, nicknamed “pink,” was showing up as a powder and in counterfeit pills made to look like pharmaceutical opioids, often in people who did not know they were taking it. Emergency scheduling of one molecule was supposed to close the door. A decade later the same chemical family is being reported on another continent, in a place that had never found it. The lesson of 2016 is the lesson of every ban on a single compound: a chemist can change a few atoms faster than a legislature can change a schedule. Burnet’s researchers say the same thing about nitazenes now, that rapid evolution of variants outpaces surveillance. Prohibition chases molecules. People die in the gap between the chase and the catch.

What to do with this, whoever you are

If you use drugs, or you love someone who does, the plain advice does not change just because the chemical name is unfamiliar. The thing still available to you is naloxone: carry it, keep it where others can find it, and tell the people around you where it is. Because a substance that acts within minutes leaves little room, the person nearby is the intervention. If a drug checking service exists where you live, use it. If it doesn’t, ask your local harm reduction group why.

If you work in a clinic, an emergency department or a recovery program, three things are worth doing this week. First, ask intake staff to record whether a patient believed they had taken one substance and the presentation suggests another, because the Australian data suggests that mismatch is the signature. Second, confirm that whoever is on shift knows the standard naloxone dose and the instruction to repeat it, since the research found standard dosing worked in most cases. Third, find out whether your lab’s toxicology can detect novel synthetic opioids at all, and if it cannot, tell your medical director so the gap is on someone’s list. We covered the same kind of unseen-sedative problem in our reporting on medetomidine, and you can find more on how we track the novel and emerging substances and the harm reduction beat.

Tasmania’s health department could not tell the public what the person who died took. It could tell them what to do next: have naloxone ready. That is a small instruction, and it is the one that has a record of working.