Sweden's Efforts Curb Nitazener Drug Deaths

The life-threatening drug Nitazener has killed hundreds of people around Europe. But thanks to a sharp warning from the police, the death toll in Sweden is relatively low. The police efforts have strangled the supply, says the National Board of Forensic Medicine's chief toxicologist Robert Kronstrand.

» Published: August 07 2025

According to the Wall Street Journal, for example, at least 400 Britons have died from Nitazener overdoses in the last 18 months. The drug, which is a very potent synthetic opioid, has also claimed victims in Sweden. But after, among other things, the police and the National Board of Forensic Medicine last autumn issued a sharp warning about Nitazener, the death toll has decreased.

We had many deaths in Sweden until 2024, then it decreased. This year, there are four cases where we have found Nitazen in some autopsy case, says the National Board of Forensic Medicine's chief toxicologist Robert Kronstrand.

Respiratory depression

What is it about Nitazener that is so incredibly dangerous?

Robert Kronstrand explains.

Nitazener is a collective name, and a Nitazen is a substance that resembles Fentanyl, i.e. a strong pain-relieving preparation used in healthcare. The danger of Nitazener is that it can cause respiratory depression, just like Fentanyl or heroin. Nitazener can cause such serious side effects that you stop breathing and die.

Nitazener, which is often imported from China, is considered to be significantly stronger than both Fentanyl and heroin. And just like with the more well-known opiates, the user develops a tolerance.

There is a human study on Metonitazen, which has been most common in Sweden, where they gave it to test subjects with intramuscular injection and then saw that some got respiratory depressive effects when they gave them one milligram, i.e. one thousandth of a gram. It's very little, like a very small part of a sugar cube, says Kronstrand.

Sites shut down

In connection with the warning last autumn, the police carried out a number of measures that, according to Robert Kronstrand, may have saved many lives.