New research from King’s College London suggests the true scale of deaths linked to synthetic opioids may be far higher than official figures show. Scientists warn that nitazene deaths in the UK are likely undercounted by as much as a third, raising urgent questions about the data that shapes the country’s drug harm reduction response.

Nitazenes are a group of synthetic opioids first developed in the 1950s as potential painkillers. Researchers abandoned them after recognising that their extreme potency made them dangerously addictive. At up to 500 times stronger than heroin, the drugs were simply too dangerous to bring to market. Decades later, they have re-emerged on illicit drug markets, and people are dying.

Nitazene Deaths in the UK: Why Official Numbers Fall Short

In 2024, the National Crime Agency recorded 333 UK fatalities connected to nitazenes. That figure is now believed to be a substantial underestimate. King’s College London researchers found that nitazenes degrade rapidly after death. By the time pathologists test postmortem blood samples under standard laboratory conditions, the drug may be almost entirely undetectable.

The research team tested samples from rats anaesthetised with nitazenes. On average, only 14% of the substance present at the point of overdose remained detectable under real-world handling conditions. Researchers then applied that finding to mortality data from the UK National Programme on Substance Use Mortality. They found an excess of unexplained drug deaths in Birmingham in 2023, roughly a third more than recorded nitazene fatalities would suggest.

Toxicology tests are simply not catching the drug before it breaks down. That means a significant portion of nitazene deaths in the UK go unrecognised.

“We Are Trying to Tackle a Crisis Using Incomplete Data”

Dr Caroline Copeland, senior lecturer in pharmacology and toxicology at King’s College London and lead author of the study, did not mince her words.

“If nitazenes are degrading in postmortem blood samples, then we are almost certainly undercounting the true number of deaths that they are causing,” she said. “That means we are trying to tackle a crisis using incomplete data. When we do not measure a problem properly, we do not design the right interventions, and preventable deaths will continue.”

Dr Copeland added: “Behind this undercount are people dying suddenly from extremely potent opioids, families left without answers, and communities facing a growing but largely hidden toll.”

This is not merely a statistical problem. Drug-related mortality data directly shapes how government funding gets allocated and which harm reduction strategies receive investment. Policymakers cannot design the right response to a crisis they are not fully measuring.

Synthetic Opioid Deaths in the UK: A Broader Epidemic

Nitazenes are not the only synthetic opioid causing alarm. Health experts in Scotland have warned of a fresh drug deaths crisis, with more than 100 fatalities already linked to highly potent synthetic substances in that country alone. Across the UK, over 17,000 people die from drug or alcohol-related causes every single year.

Mike Trace, chief executive of the Forward Trust and co-creator of the UK’s first national drug strategy, welcomed the research and called for bolder action.

“The extreme potency of nitazenes has clearly contributed to rising overdose and death rates amongst people who use drugs,” he said. “This research shows the official numbers are probably underestimates, supporting our calls for the government to be braver in rolling out drug testing and overdose prevention measures to save lives.”

He continued: “With over 17,000 people per year across the UK dying from drug or alcohol-related causes, we cannot afford to be hesitant in providing lifesaving health services to people taking illegal drugs.”

What the Government Is Doing

A government spokesperson acknowledged that every drug-related death was a tragedy and confirmed that work to identify and respond to emerging threats was ongoing. Border Force has become the first agency in the world to deploy specially trained dogs capable of detecting both fentanyl and nitazenes.

Border detection matters, but it is only one part of the response. When synthetic opioid deaths go unrecorded, the full scale of the crisis stays hidden. Decisions about prevention, treatment and funding then rest on numbers that do not reflect what is actually happening.

King’s College researchers are clear: improving postmortem toxicology testing for nitazenes is not a technical detail. It is a public health necessity. Without accurate data, the right interventions will never reach the people who need them most.

Source: theguardian