Why were nitazenes created?

Nitazenes were original developed in the 1950s by scientists in Switzerland looking for ways to treat severe pain, particularly when existing opioids like morphine or diamorphine weren’t strong enough. However, they were never approved for medical use because of their high potency, enormous risk of overdose, and lack of increased benefit compared to other licensed medications.

Today, nitazenes have emerged on the illicit drug market. Some nitazenes can be up to 500 times stronger than heroin, posing a serious risk of overdose, even in extremely small amounts.

Types of nitazene

There are several types of nitazenes which vary in potency, including:

• Protonitazene
• Metonitazene
• Isonitazene
• Etonitazene

Nitazenes are predominantly found in contaminated batches of heroin and other opioids, as well as counterfeit oxycontin tablets, unknown pills (thought to be purchased as ecstasy), cannabis vapes, ketamine and cocaine.

Most of the nitazenes sold on British streets are thought to arrive from China, where they are manufactured and sold through online markets in large wholesale quantities. The small size of the drug relative to its potency makes nitazenes easier to smuggle through the post than other opioids.

Stronger than other opioids

Nitazenes carry similar but increased health risks as other opioids, which include a high propensity for dependency, as well as significant risk of overdose and fatality. The risks for nitazenes are particularly high given they are many hundred times more potent than most other opioids.

According to the UN World Drug Report 2025, some nitazenes are up to 500 times stronger than heroin, which itself is around three times stronger than morphine. Other nitazenes are also several times stronger than fentanyl.

How many people have died after taking nitazenes?

In the UK, there have been at least 400 recorded deaths involving nitazenes. However, this has been described as “the tip of the iceberg” by The Lancet, with the actual figure thought to be significantly higher. This is due to a lag in reporting data and the fact that nitazenes have only recently started being tested for in post-mortem examinations.

Figures released by National Records of Scotland showed the sharp rise in nitazene deaths: after one death attributable to nitazenes in the years from 2000 to 2022, there were 23 deaths in Scotland linked to this class of drugs in 2023.

Punishments for nitazene use and supply

As of 2023, nitazenes are classified as a Class-A controlled substance under the Misuse of Drugs Act 1971, with possession carrying a sentence of up to seven years in prison.

The maximum penalty for producing or supplying nitazenes is life imprisonment, with police and border control agencies intercepting several attempts to import them in tablet and powder form.

The UK government released a “nitazenes preparedness plan” in 2025, which aims to communicate and enact a strategy to address the issues associated with these substances. The government has also created early warning systems and re-introduced the use of waste water testing to better understand the prevalence of nitazenes in the drug supply.

Our view on nitazenes

Cranstoun believes that the threat of nitazenes is cause for alarm, and without evidence-based interventions, could lead to a public health emergency like we have seen with fentanyl in North America.

We’ve launched a report outlining our harm reduction plan, which includes:

• Expanding drug testing services
• Establishing overdose prevention centres (OPCs)
• Increasing access to treatment and support

We’re also advocating for a whole-system approach to tackle the spread of synthetic opioids and prevent further loss of life.