Fentanyl is already familiar to many – primarily because of its key role in the opioid crisis in the United States. Nitazenes, however, are less well known. However, they also belong to the synthetic opioids – and are currently spreading very quickly. Even the smallest amounts, barely visible to the naked eye, can have a deadly effect. Young people are often affected.
A new analysis shows that the number of unreported cases is much higher than statistics have previously suggested. According to a British study published in the journal Clinical Toxicology, there are a third more deaths caused by nitazoxanide than previously reported.
One reason is that these substances break down very quickly in blood samples after death. When toxicology analysis is needed to determine the cause of death, they are often difficult to detect.
What are nitazenes?
Nitazenes are among the most potent opioids – some members of this group can be up to 500 times more potent than heroin, according to experts led by Caroline Coupland of King’s College London. They were originally developed in the 1950s as potential analgesics – they are cheap and easy to produce. However, they have never been approved for medical use due to their extreme potency and high risk of overdose.
According to the German Observatory for Drugs and Addiction (DBDD), nitazines are consumed in very different forms – as vape liquid, as tablets, rolling papers or in other mixtures.
Nitazenes have psychoactive effects, which according to the World Health Organization (WHO) means that they "affect mental processes, including perception, consciousness, cognitive abilities, mood and emotions."
High risk of overdose
Signs of overdose include loss of consciousness, seizures, and severe sedation, followed by respiratory arrest. The therapeutic range – the difference between the effective and lethal dose – is extremely small. This is why even a single use can quickly become life-threatening.
Researchers led by Caroline Coupland simulated a typical toxicology test using animal experiments. In the UK, it usually takes about four weeks before blood samples are tested. At that point, on average, only 14 percent of the initial amount of the substance can still be detected – a key factor in why deaths are often not attributed to nitazoxanide. Based on the modelling, the scientific team concluded that the actual death rate is about a third higher than the recorded rate.
"If we don't measure the problem properly, we can't develop adequate measures – and the inevitable consequence is that avoidable deaths will continue to occur," warns Coupland. Finding typical metabolites of nitazene and developing methods to detect them could lead to better data in the future.
Germany: Only 40 percent of deaths are toxicologically tested
In Germany, the exact cause of death in drug-related cases is only determined on an individual basis anyway, according to the German Center for Drug Monitoring and Drug Addiction (DBDD). "In 2024, toxicology reports were only made in 40 percent of drug-related deaths."
And that's complicated - in about 80 percent of such cases, multiple substances were consumed, which often makes it impossible to clearly determine the cause of death.
Nitazenes conquer the drug market in Europe
The European Drugs Agency (EUDA) reports that in 2024, out of the nearly 50 new psychoactive substances reported in the EU, around half belonged to the nitazene group. Their presence on the European drug market has increased enormously over the past seven years. According to the Royal College, international institutions have already issued numerous warning reports. According to the DBDD, nitazenes were already among the most frequently registered substances within the synthetic opioids in 2023 and 2024. This group also includes well-known substances such as fentanyl or tramadol.
Young people are particularly vulnerable to nitazene
The Institute for Therapeutic Research in Munich reports that nitazene is particularly used by young people who are prone to experimenting with drugs. Several tragic cases have been documented in Germany. The United Kingdom reported more than 330 deaths linked to nitazene in 2024, many of the victims being very young.
For Germany, the DBDD registered a total of 32 deaths related to synthetic opioids in 2024, and in nine cases, the consumption of nitazene was explicitly confirmed. There are no complete data for 2025 yet.
Synthetic opioids – constantly new variants
Experts believe that the number of unreported cases is significantly higher – partly due to incomplete toxicological analyses, and partly because new substances are constantly appearing. For example, in 2025, new so-called orphins such as cyclorphin – another subgroup of opioids – were registered.
"One of the dangers of new synthetic opioids is that they can be found, for example, in counterfeit medicines that look completely authentic," it says. If accidentally consumed by people without a developed tolerance to opioids, it can be fatal for them within minutes.
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