Source: The Conversation – UK – By Philip A. Berry, Visiting Research Fellow, King’s College London
In the early hours of September 14 2021, three men parked in a quiet car park in the southern English market town of Abingdon-on-Thames. The men, returning from a night out, had pulled over to smoke heroin.
Unknown to them, the drug had been fortified with a nitazene compound called isotonitazene, a highly potent new synthetic opioid. Two of the men, Peter Haslam and Adrian Davies, overdosed and went into cardiac arrest. The third, Michael Parsons, tried to save them and himself by injecting naloxone, an opioid overdose antidote. Despite paramedics also trying to resuscitate Haslam and Davies, both died at the scene.
Their deaths were among at least 27 fatalities linked to nitazenes that year in the UK. Since then, nitazenes – otherwise known as 2-benzylbenzimidazole opioids – have become more prevalent in the UK’s illegal drug supply, leading some experts to warn that they are a major new threat because of their extreme potency.
In June 2023, the UK’s most recent outbreak of deaths linked to synthetic opioids emerged in the West Midlands when drug dealers used nitazenes to fortify low-purity heroin. By August, there were 21 nitazene-related fatalities in Birmingham alone. In some cases, dealers also added xylazine (colloquially known as “tranq”), a non-opioid sedative used by vets.
The increasing availability of these and other synthetic drugs led the UK’s National Crime Agency (NCA) to warn in August 2024 that “there has never been a more dangerous time to take drugs”. Like Haslam and Davies, many heroin users are unaware they might also be consuming nitazenes, which significantly increase the risk of overdose.
Given their potency, only a small amount of nitazene is required to produce a fatal dose. While some studies have concluded that nitazenes are even more potent than the synthetic opioid fentanyl, which causes many thousands of deaths in the US, the NCA judges it a “realistic possibility” that the potency of both substances are “broadly equivalent” – making them roughly 50 times more potent than heroin.
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Officially, more than 400 deaths plus many non-fatal overdoses were linked to nitazenes in the UK between June 2023 and January 2025. But this is likely to be an underestimate because of gaps within forensic and toxicology reporting. These figures come amid record levels of drug-related deaths in England and Wales. In 2023, there were 5,448 deaths related to drug poisoning, an 11% increase on the previous year and the highest total since records began in 1993.
This is of particular concern given that the UK has the largest heroin market in Europe, comprising around 300,000 users in England alone. While nitazene-related deaths are still relatively low (although by no means insignificant) compared with those from heroin and other opioids, these new synthetic opioids are cheap and easy to buy, and offer dealers multiple advantages over traditional plant-based drugs.
Unlike opium, nitazenes and other synthetic opioids can be produced anywhere in the world using precursor chemicals that are often uncontrolled and widely available. Producer countries including China and India have not yet banned all nitazene compounds, meaning they are sold legally – mostly online. Chemical manufacturing companies in these countries can synthesise nitazenes at scale using a comparatively easy three or four-step process.
Opioid use death rates around the world:
Our World In Data, CC BY
For the past 15 years, I have researched and advised on the international narcotics industry, especially the Afghan drug trade, as an academic, UK Home Office official and consultant. I’ve observed many shifts within global drug markets, and I believe the increasing availability of synthetic drugs in the UK and Europe may represent a new chapter in illicit drug use here – with the emergence of nitazenes only adding to these concerns.
A brief history of synthetic opioids
New synthetic opioids (NSOs) are one of the fastest-growing groups of new psychoactive substances around the world. The EU Drugs Agency (EUDA) currently monitors 81 NSOs – the fourth-largest group of drugs under observation.
NSOs largely fall into two broad groups: fentanyl and its analogues, and non-fentanyl-structured compounds – these include nitazenes, among many other substances.
Many of these “new” synthetic opioids have, in fact, existed for decades. Nitazenes were first synthesised in the 1950s by the Swiss pharmaceutical company, Ciba Aktiengesellschaft, as pain-relieving analgesics, although they were never approved for medical use.
Prior to 2019, there had only been limited reports of nitazenes in the illegal drug supply – including a “brownish looking powder” found in Italy in 1966; the discovery of a lab in Germany in 1987; several nitazene-related deaths in Moscow in 1998; and a US chemist illegally producing the drug for personal use in 2003. But since nitazenes re-emerged at the end of the last decade, over 20 variants have been discovered.
Johnson & Johnson
The most common NSO in the illegal drug market, fentanyl, was first synthesised by Belgian chemist Paul Janssen in 1960. Fentanyl, which is roughly 100 times more potent than morphine, was approved in the US in 1968 for pharmaceutical use as an analgesic.
Over the next four decades, however, illegally produced fentanyl resulted in three relatively small outbreaks of deaths in the US. A fourth, larger fentanyl outbreak in Chicago, Detroit and Philadelphia resulted in about 1,000 deaths between 2005 and 2007.
The current US fentanyl crisis started in 2013, expanding to affect much of the country. Between 2014 and 2019, Chinese companies were the main manufacturers of finished fentanyl substances in the US – to combat this, both the Obama and Trump administrations lobbied Beijing to curtail the fentanyl industry.
The Chinese government responded by controlling specific fentanyl analogues. However, every time an analogue was banned, chemists there would slightly adjust the formula to produce a new compound that mirrored the banned substance.
China finally banned all fentanyl-related substances in May 2019, prompting two significant changes in the drug’s supply: a slowdown in the development of new fentanyl analogues, and a reduction in their direct sale to the US from China. Instead, Chinese companies increasingly sent fentanyl precursors to Mexican drug cartels who would synthesise fentanyl (or counterfeit medication) in clandestine labs, before smuggling it across the US border. Consequently, Mexico is now the primary source of fentanyl in the US.
But these supply changes led to another shift in the global drugs arena, as China’s chemical and pharmaceutical businesses – keen to develop new markets – adjusted their focus to producing uncontrolled synthetic substances, including nitazenes. At the same time, they expanded their geographical focus from North America to include Europe and the UK.
The nitazene supply chain
Producing nitazenes is a relatively low-cost exercise. They are largely manufactured in laboratories – both legal and illegal – in China, before being smuggled to the UK and Europe via fast parcel and post networks.
Nitazenes’ high potency means only small quantities are required, making them easier to transport and harder for border officials to detect. Some Chinese vendors have reportedly been offering to hide nitazenes in legitimate goods such as dog food and catering supplies, to circumvent custom controls. All of this decreases the risk to sellers, and lessens the price of doing business.
In March 2024, two China-based sellers operating on the dark web were selling a kilo of nitazene for between €10,000 and €17,000 (£12,000-£20,000). During roughly the same period, a kilo of heroin at the wholesale level in the UK was selling for between £23,000 and £26,000. Once bought, nitazenes are largely used to fortify low-purity heroin, although the drug can also be made into pills.
Nitazenes are not limited to the dark web. They are widely and openly advertised on the internet, social media and music streaming platforms. In February 2024, one China-based e-commerce site displayed 85 advertisements for nitazenes. Such sites also sell a range of other synthetic drugs, including fentanyl analogues and precursors, xylazines, cannabinoids and methamphetamine.
This means drug dealers in the UK and across the world no longer need to have established connections to underworld figures to source illegal drugs. With a click of a mouse, they can have them delivered to their home address. In this sense, the internet has democratised the drug trade by widening access beyond “traditional” criminals.
In the UK, while the supply of nitazenes is currently assessed as “low”, a number of smaller-scale organised crime groups are importing them to fortify low-purity heroin, before largely dealing it at the “county lines” level. This involves organised crime groups moving drugs – primarily heroin and crack cocaine – across towns, cities and county borders within the UK, using mobile phones or another form of “deal line” to sell to customers.
In November 2023, Leon Brown from West Bromwich was imprisoned for seven years for dealing drugs containing nitazenes – a verdict described as “a great result in our ongoing efforts to tackle county lines drug dealing” by detective sergeant Luke Papps of the South Worcestershire county lines team.
A few larger UK criminal networks have also been involved in nitazene distribution. In October 2023, the police and Border Force conducted raids across north London, arresting 11 people. They dismantled a drug processing site and seized 150,000 tablets containing nitazene – the UK’s largest ever seizure of synthetic opioids – as well as a pill-pressing machine, a firearm, more than £60,000 in cash and £8,000 in cryptocurrency. The police suspected the group had been selling the tablets on the dark web.
Anecdotal reports suggest there have been mixed reactions to the introduction of nitazenes into the illegal drug supply. Richard, a recovering heroin user from Bristol, told Vice magazine that, given their potency, some “people are scared of [nitazenes]” while others are “actively seeking” them.
As has been the case with fentanyl in the US, users build up tolerance and therefore seek stronger doses. Manny, a heroin user from Bristol, told Vice: “I smoked [heroin cut with nitazenes] and it felt like the first time I’d ever taken drugs.”
UK-based criminals also use the dark web to export nitazenes abroad. In October 2023, the Australian Border Force identified 22 nitazene discoveries in packages shipped to the country via mail cargo from the UK. British criminals have also trafficked counterfeit medicines containing nitazenes to Ireland and Norway.
Use of nitazenes is now being detected all over the world. Within Europe, Ireland experienced several nitazene outbreaks in 2023-24 while in Estonia, nitazenes now account for a large share of overdose deaths – a trend also seen (to a lesser extent) in Latvia. Preliminary data suggests at least 150 deaths were linked to nitazenes in Europe in 2023.
Nitazenes have also been discovered in fake pain medication such as benzodiazepines, oxycodone and diazepam, which widens the number of people at risk to include those with no opioid tolerance. The death in July 2023 of Alex Harpum, a 23-year-old British student who was preparing for a career as an opera singer, was a stark reminder of the danger of buying fake medicine online that may have been contaminated with nitazenes.
The nitazene ‘boom’ and the global heroin trade
For decades, Afghanistan was the world’s largest opium producer and the source of most of Europe’s heroin. Then in April 2022, the ruling Taliban announced a comprehensive prohibition on the use, trade, transport, production, import and export of all drugs. As a result, poppy cultivation has fallen to historically low levels for a second consecutive year.
While this has not, as yet, translated into a shortage of heroin on European streets, including in the UK and Germany, some indicators suggest a slowdown in heroin supplies to the UK. In the year March 2023-24, the quantity of heroin seized in the UK fell by 54%, from 950kg to 441kg. This is the lowest quantity of heroin seized since 1989, when about 350kg was intercepted.
The NCA assesses that the Taliban ban has created market “uncertainty”. The wholesale price of heroin has increased from roughly £16,000 per kilo prior to the COVID-19 pandemic to about £26,000, while anecdotal reports suggest average heroin purity for users dropped to under 30% (often to 10-20%) in 2024, compared with around 35% in 2023 and 45% in 2022.
Even without the Taliban’s ban, heroin is not easy to produce and supply. Cultivating opium poppy is labour-intensive, taking five or six months. The static nature of opium fields means they are visible and susceptible to eradication; poppy crops can also be negatively affected by blight or drought.
Converting opium into heroin base is also a labour-intensive process that can involve (depending on the production method) at least 17 steps. Acetic anhydride, the main chemical used to convert morphine into heroin, is relatively expensive compared with synthetic precursors. Moreover, heroin is a bulky product, which means it is harder to move in large volumes.
While the relationship between events in opiate-producer countries and the introduction of synthetic opioids to consumer markets should not be overstated, this new type of drug offers economic advantages to criminals whose “sole motivation is greed”.
For decades, Turkish, Kurdish and Pakistani criminal networks have been responsible for importing heroin into the UK. Once in the UK, both Turkish and British groups largely control its wholesale supply, with some participation of Albanian gangs.
To date, there is little evidence to suggest these groups have transitioned to supplying NSOs, including nitazenes. The shifting dynamics in the global drug supply chain, however, could upend traditional markets and the gangs who profit from them.
America’s synthetic drug crisis
The synthetic opioid fentanyl has devastated the US, having been linked to about 75,000 deaths in 2023 alone. It is the primary cause of death for Americans aged 18-49. Canada, too, has experienced a wave of deaths: between January 2016 and June 2024, there were 49,105 apparent opioid deaths there, with fentanyl implicated in a large proportion.
While the North American nitazene market is still small in comparison, the US, followed by Canada, has reported the highest number of unique nitazenes to the UN Office on Drugs and Crime’s Early Warning Advisory on New Psychoactive Substances.
More than 4,300 reports of nitazenes have reached the US National Forensic Laboratory Information System since 2019. They are typically used to fortify fentanyl and other opioids, which can produce a fatal concoction.
Efforts to stem the flow of NSOs, including nitazenes, from China to the US and elsewhere will prove challenging. And even if China does implement stricter controls, other countries could step in to fill the void. According to the Commission on Combating Synthetic Opioid Trafficking:
The overall sizes of these industries, limited oversight efforts and political incentives contribute to an atmosphere of impunity among firms and individuals associated with those industries.
While US and Chinese counter-narcotics cooperation ended in 2022 amid increasing geopolitical tensions, the following November’s summit in Woodside, California, between presidents Joe Biden and Xi Jinping saw them agree to recommence collaboration.
As a result, China recently closed several chemical companies that were shipping fentanyl precursors and nitazenes to the US. These vendors used encrypted platforms and cryptocurrency to conduct the deals, and mislabelled the consignments to try to ensure the substances evaded border controls. China has also outlawed more chemicals and substances, including several nitazene variants.
But President Trump’s imposition of tariffs on imports from China – which sit alongside proposed taxes on imports from Canada and Mexico, in part for supposedly not doing enough to curb the trafficking of fentanyl and its precursors to the US – threatens this counter-narcotics cooperation.
While nitazenes are not yet widely available in the US, their presence within some fentanyl batches is complicating the US opioid crisis – and according to some experts, has the potential to further increase the already shocking number of synthetic opioid-related deaths.
The UK response to nitazenes
Successive UK governments have made tackling NSOs a high priority. Shortly after the most recent nitazene-related deaths were discovered in the UK in summer 2023, the NCA launched Project Housebuilder to lead and coordinate the law enforcement and public health response.
This was soon followed by the establishment of a government-wide Synthetic Opioids Taskforce “to improve…understanding, preparedness and mitigation against this evolving threat”. Chris Philp, then the UK’s combatting drugs minister, stated that “synthetic opioids are at the top of [this government’s] list because of the harm they cause”.
The taskforce has taken a range of measures, such as controlling more NSOs as class A drugs, conducting more intelligence operations at UK borders, widening access to naloxone, and enhancing the UK’s real-time, multi-source drug surveillance system. The government also worked with the US and Canada to learn from their experiences.
Recently, the current UK government banned a further six synthetic opioids and introduced a generic definition of nitazenes as class A drugs. And the UK’s current government, unlike its Conservative predecessor, has also indicated its willingness to consider evidence from the UK’s first drug consumption facility, which recently opened in Glasgow.
Other policy measures worthy of consideration include expanding drug checking services whereby drug users submit drugs to a lab to test what is in them, then are provided with information about the sample. These services offer vital information to the public and authorities about current drug trends.
While there is high uncertainty about what is going to happen next in the UK regarding illicit drug trends, the evolution of the US drug landscape over generations provides some important lessons.
Lessons from the US
The US fentanyl crisis shows drug markets can change quickly with long-lasting consequences. Most heroin on US streets contains – or has been replaced by – fentanyl. According to DEA seizure data, US heroin seizures declined by nearly 70% between 2019 and 2023, whereas fentanyl seizures have increased by 451%.
However, illegal drug markets evolve in different ways and at different paces. In May 1989, Douglas Hogg, a UK Home Office minister, travelled to the US and the Bahamas on a fact-finding mission about crack cocaine, a drug that was predicted to spread from the US to the UK. Upon his return, Hogg noted:
The ethnic, social and economic characters of many of our big cities are very similar to those in the US. If they have a crack problem, why should not we? … The use of crack in Great Britain is likely to develop very substantially over the next few years.
But this “crack invasion”, as some called it, did not materialise in the UK to the extent it had in the US – and the same was true about a predicted wave of methamphetamine use in the UK, which remains low compared with the US.
It is also unlikely the UK and Europe will experience a synthetic opioid crisis on the same scale as the US. The first wave of the US crisis was driven by extensive overprescription of opioids for pain relief. This increased the number of people addicted to opioids, some of whom later turned to heroin, before transitioning to fentanyl. In contrast, large-scale opioid prescriptions have not been a major issue in the UK or Europe, although there is some diversion of legal fentanyl into the illegal drug market in Europe.
According to Alex Stevens, professor of criminology at the University of Sheffield, another factor differentiating the US and Europe is the provision of drug treatment and harm reduction programmes. Opioid users in Europe, and to a lesser extent in the UK, are much more likely to be in medication-assisted treatment than their US counterparts, thus reducing the number of people at risk. These interventions are reinforced by different socioeconomic factors in much of Europe, such as lower economic inequality, stronger social protections, and better healthcare systems.
None of this, though, means the nitazene threat in the UK and Europe should be underestimated, nor that use and supply of these drugs (and other NSOs) will not increase from its current relatively low base. As the NCA recently warned:
While a zero-tolerance approach from law enforcement, plus advice to users on the heightened dangers, may contain or slow the current uptake, we must prepare for these substances to become widely available, both unadvertised in fortified mixes and in response to user demand as a more potent high.
The future of new synthetic opioids
Predicting the future of NSO use and trafficking is a challenging task. Projections for Europe range from existing opiate stockpiles ensuring that heroin consumer markets remain serviced (assuming the Taliban ban is short-lived), to a heroin shortage which results in more drug dealers turning to NSOs to plug the shortfall, which in turn could lead to lasting changes in European drug markets (as happened in a few countries following the Taliban’s first opium ban in 2000-01).
In such a scenario, it is possible that Turkish criminal networks may exploit their links with Mexico’s Sinaloa cartel to source NSOs. Mexican criminal gangs also operate in Europe, which may increase the likelihood of them trying to open a new NSO market on the continent.
There is also evidence that some Italian criminal organisations have entered the NSO marketplace. In November 2023, Italian authorities announced the seizure of 100,000 doses of synthetic drugs, including fentanyl, as part of operation Painkiller, a joint Italian-American initiative.
Given the many advantages for criminal groups of NSOs, it seems likely they are here to stay. A key question is whether nitazenes (or other NSOs) will supplant traditional heroin as the opioid of choice, as they have done in the US, or remain at relatively low levels in Europe, co-existing with or mixed into the heroin supply.
In December 2023, Paul Griffiths, the EUDA’s scientific director, told Vice: “We’re not seeing much new initiation of heroin use in Europe. So in five to ten years … as heroin users get older and more vulnerable, we’re not going to have much of an opiate problem left.”
But he warned that if heroin use does dry up: “You might then see opioids appearing in other forms and preparations, such as pills, that could potentially become popular among younger age groups who currently do not appear attracted to injecting heroin.”
While previous NSO outbreaks in the UK were relatively short-lived and limited in scale, the most recent nitazene outbreak, which started in summer of 2023, has been more sustained, covered more parts of the UK, and involved more fatalities. The broader trend in Europe also suggests the prevalence and variations of NSOs are increasing at a faster pace than in previous years.
Notwithstanding, nitazene use and supply in the UK currently remains relatively low. In fact, the rate of nitazene-linked deaths – at least those officially reported – decreased between spring 2024 and the end of the year.
In the short term, then, it seems unlikely there will be a nitazene “explosion”. Rather, criminal groups will probably try to increasingly embed nitazenes into the UK drug market at a similar pace to the last 18 months.
However, this situation could change rapidly in future, especially if larger criminal networks involved in heroin importation switch to smuggling NSOs, and there is a genuine shortage of Afghan heroin. This problem would be compounded if drug users start seeking nitazenes, thus creating demand for them.
Either way, the UK government, along with its European partners, should continue to reinforce the whole drug system, to prepare for the worst-case scenario.
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Philip A. Berry does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
– ref. ‘There has never been a more dangerous time to take drugs’: the rising global threat of nitazenes and synthetic opioids – https://theconversation.com/there-has-never-been-a-more-dangerous-time-to-take-drugs-the-rising-global-threat-of-nitazenes-and-synthetic-opioids-247268
