UK Government Bans 15 Synthetic Opioids

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More synthetic opioids have been placed under the strictest controls in the United Kingdom.

The government of the United Kingdom announced on March 20, 2024 that it is banning a further 15 synthetic opioids that are considered highly addictive, dangerous, and pose a higher risk of accidental overdose (1). These substances will now be subjected to the strictest controls, in line with the controls placed on fentanyl.

As a result of these new government controls, if anyone is involved in the production or supply of the synthetic opioids, they will be subjected to the full force of the law. “We are highly alert to the threat from synthetic drugs and have been taking a range of preventative action, learning from experiences around the globe,” said James Cleverly, UK home secretary in a press release. “Our plan is working—the overall quantities of synthetic opioids reaching the UK remain lower than other countries, but we are not complacent.”

Synthetic opioids are a major contributor to preventable drug overdose deaths, particularly affecting the United States. However, Europe is also now fearing a crisis, as the availability of these drugs is increasing (2). Although opioids can be prescribed for pain relief, any regular non-medical use, prolonged use, misuse, or use without medical supervision can result in dependence on the drug and various related health problems (3).

Of the 15 synthetic opioids, 14 are nitazenes, which were developed by the pharmaceutical industry during the 1950s but were never approved for use as medicines and can cause fatal respiratory depression. Some nitazenes are known to be hundreds of times more potent than heroin, and these compounds are being detected in other products, meaning consumers may be using these substances without realizing (4).

“Synthetic opioids are significantly more toxic than heroin and have led to thousands of deaths overseas,” added Chris Philp, UK’s crime and policing minister. “We are determined to ensure these destructive and lethal drugs do not take hold in our communities in the UK.”


The opioids that have been made Class A drugs under the UK’s Misuse of Drugs Act 1971 are metonitazene; protonitazene; isotonitazene; butonitazene; flunitazene; metodesnitazene (metazene); etodesnitazene (etazene); N-pyrrolidino-etonitazene (etonitazepyne); N-piperidinyl-etonitazene (Etonitazepipne); N-pyrrolidino protonitazene; ethyleneoxynitazene; N-desethyl protonitazene; N-desethylisotonitazene; N-desethyl-etonitazene; and brorphine.

Additionally, the UK government has placed controls on five other substances on March 20, 2024. Of these substances, three are stimulants—diphenidine, ephenidine, and methoxyphenidine—that are now Class B drugs; one is a synthetic cannabinoid receptor agonist (cumyl-PeGaClone) that is also now a Class B drug; and the final one is a short-acting benzodiazepine (remimazolam), which is now a Class C drug.


1. UK Gov. More Synthetic Opioids Banned to Protect Communities., News Story, March 20, 2024.
2. Bauer-Babef, C. Opioids on the Rise, Under Close Surveillance in Europe. Euractiv, March 6, 2024.
3. WHO. Opioid Overdose., Fact Sheet, Aug. 29, 2023.
4. Holland, A.; Copeland, C.S.; Shorter, G.W.; et al. Nitazenes—Heralding a Second Wave for the UK Drug-Related Death Crisis? The Lancet, 2024, 9 (2), E71–E72.

Source: UK Gov