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Synthetic Opioids to Be Banned in UK

The Government is to ban synthetic opioids in a step to prevent further deaths from drugs, with 11 more lethal substances to be made Class A drugs. None of the drugs have been licensed for medical use.

Following a recommendation by the Advisory Council on the Misuse of Drugs (ACMD) 11 synthetic opioids will be banned in the UK, the Home Office has announced, in an effort to "stop lethal drugs claiming more lives".

"On the recommendation of the Advisory Council on the Misuse of Drugs (ACMD) 10 additional nitazenes and brorphine will be made Class A substances," a Home Office spokesperson said.

The substances to be added to Class A of the Misuse of Drugs Act 1971, subject to Parliamentary approval, are: butonitazene, etodesnitazene (etazene), flunitazene, isotonitazene, metodesnitazene (metazene), metonitazene, N-Desethylisotonitazene, N-piperidinyl-etonitazene (etonitazepipne), N-pyrrolidino-etonitazene (etonitazepyne), protonitazene, and brorphine.

These drugs are psychoactive substances and can be more potent than fentanyl, explained the Home Office spokesperson, who added that the drugs were often mixed into other pills sold on the street.

Policing Minister Chris Philp said: "Synthetic opioids are highly dangerous substances, which ruin lives and devastate communities."

There has been a "dramatic increase" in opioid mortality in the UK since 2008, according to a Lancet study. In England between April 2010 and March 2017, a total of 280,827 people were admitted to hospital due to an opioid overdose and 14,700 people died from opioids, according to data from 152 local authorities. 

"To protect lives, their possession will now be illegal and anyone who supplies the drugs will face up to life in prison, an unlimited fine or both," the Home Office spokesperson said.

However, asked to comment by Medscape News UK, a spokesperson for the charity Release warned that: "Adding these substances to the list of controlled drugs will not prevent them entering the market, as is the case with other controlled substances", and added that "criminalisation creates barriers to support, and can increase the harms faced by people who [use] drugs".

Substantial Public Health Challenge

The Government commissioned the ACMD to investigate these drugs after the substances were linked to rising overdoses in other countries, and to provide a review of the evidence on the use and harms of 2-benzyl benzimidazole (nitazene) and piperidine benzimidazolone (brorphine-like) opioids.

The ACDM report considered two similar but distinct types of new syntheticopioids - the 2-benzyl benzimidazole, 'nitazene', and the piperidine benzimidazolone, 'brorphine- like', opioids.

The authors of the report explained that new psychoactive substances have presented a "substantial public health challenge" over the last 13 years, with new synthetic opioids making an increasing recent contribution.

They explained that new synthetic opioids gave users similar effects to those of morphine and heroin, but "some are much more potent". This meant that substantially lower doses were needed to achieve the effects desired by users, they alluded, and cautioned there is also a "high risk of accidental overdose". This may cause life-threatening toxicity, including loss of consciousness, cardiorespiratory arrest, and death, they warned, and was consistent with the effects of established potent opioids such as fentanyl.

"The unregulated nature of the drugs market may lead to the sale of products containing inappropriately high doses of potent compounds, or preparations containing 'hot spots' of very potent material due to inadequate blending during the cutting process," they said. "These factors increase the risk of unpredictable and severe opioid toxicity," they warned.

The ACMD found one drug, isotonitazene, was responsible for 24 fatalities in the UK in 2021 alone.

Limited Legitimate Use

The authors stressed that 2-Benzyl benzimidazole and piperidinyl benzimidazolone opioids do have legitimate uses as analytical reference standards, and potentially for research, but "no other legitimate uses" have been identified, they said.

In response to enquiries from the ACMD, the Medicines and Healthcare products Regulatory Agency (MHRA) confirmed that "none of these compounds have ever been authorised in the UK as medicines". The MHRA added that there were "no licences", either currently or previously, for any of these substances and, as a consequence, "none will have been marketed in the UK as a medicine".

Mr Philp said: "We must stop these lethal drugs from reaching our streets, to prevent more tragic deaths and other harmful consequences of addiction, from violent crime to antisocial behaviour."

In a letter to the former Home Secretary Priti Patel MP last year, ACMD chair Professor Owen Bowden-Jones and ACMD Novel Psychoactive Substances  Committee chair Professor Simon Thomas, described the report's six recommendations, which included that 2-benzyl benzimidazole (‘nitazene’) opioids, (including isotonitazene) and piperidine benzimidazolone opioids (including brorphine) should be "controlled under the Misuse of Drugs Act 1971 as Class A compound", and should be listed in Schedule 1 of the Misuse of Drugs Regulations, as they "currently have no known legitimate use".

The ACMD also recommended that 10 specific substances - including isotonitazene and brorphine - were controlled by name as soon as possible.

"Their recommendation to place all 11 narcotics in Class A has been accepted," said the Home Office spokesperson.

However, Release argued that a different approach was required. "What we need to see urgently is clear harm reduction campaigns targeting people who are likely to come in contact with this group of substances, especially as a contaminant in heroin," the charity said. "We also need drug checking services across our cities so people can test their drugs, and we need to decriminalise possession of all drugs so that people can access emergency support without fear of prosecution."


The ACMD warned that there is a risk of further related compounds being developed, so a generic chemical description allowing the wider control of 2-benzyl benzimidazole opioids was also recommended, which the Government also agreed with.

Mr Philp commented: "Drugs like these erode our society and we accept the Advisory Council on the Misuse of Drugs’ recommendations, to bring proper penalties on their supply."

With regards the other ACMD recommendations, the Government agreed with the recommendations to update information on the health effects of new synthetic opioids, and to a consultation on the generic control of 2-benzyl benzimidazole drugs variants as "new examples may be encountered" and could present a serious risk of harm.

It also agreed in principle to form a working group to establish best practice for post-mortem toxicology tests and standards for reporting in apparent drug-related deaths, but only agreed to "consider" the recommendation for adequate funding to be made available for this.