Super-strength opioids manufactured in illegal Chinese labs have been linked to at least 54 deaths in Britain in the past six months.
Nitazenes, smuggled into Britain via typical criminal routes, are mixed with heroin because they are cheap and addictive. Sometimes they are sold as oxycodone pills or Xanax powders.
As such, addicts do not always know they are consuming the substances, which can be up to 40 times more powerful than fentanyl.
Nitazenes – which ministers want to make a Class A drug like cocaine – have started flooding Britain in the past year, police forces say.
A sudden spike in deaths this summer prompted a warning from the NHS and addiction services, urging healthcare workers to be aware of the symptoms of overdoses involving synthetic opioids.
Nitazenes, which are smuggled into Britain via typical criminal routes, are mixed with heroin because they are so cheap and addictive. Sometimes they are sold as oxycodone pills or Xanax powders. As such, addicts do not always know they are consuming the substances, which can be up to 40 times more powerful than fentanyl.
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Figures shared with BBC News by the National Crime Agency (NCA) show that 17 (31 per cent) of all 54 recorded deaths from nitases were recorded in the West Midlands.
The east of England and Scotland followed, with nine deaths between June 1 and December 7.
South East England also recorded six. No deaths have been reported in Northern Ireland, Wales or the North East of England.
MarchThe actual total nationwide could be even higher, police chiefs warned Another 40 cases are still awaiting further investigation.
Nitazenes were originally developed in the 1950s by a Swiss drug company that was trying to create an alternative to painkillers.
But they never hit the market because of the high risk of overdose.
Yet its use has exploded in the US in recent years. They have been nicknamed 'Frankenstein' opioids because they are so powerful.
The drug was first discovered in Britain from a sample of white powder found in the back of a taxi in Wakefield in April 2021.
They are available in powder, tablet and liquid form and can be injected, swallowed, placed under the tongue, snorted and vaporized.
They have since been found in what users thought were black market versions of the anxiety drug diazepam and even cannabis vape liquid.
The drugs cause feelings of pain relief, euphoria, relaxation and drowsiness. But they can also lead to hallucinations, irregular heartbeat and nausea.
Nitazenes mimic the effects of natural opioids – such as morphine – and are often adulterated with these drugs, creating a deadly cocktail.
One user, who spoke to BBC News, said she 'didn't expect' how strong the drugs would be and described their effects as 'like a blanket'.
Amy, who first used heroin at the age of 16 and has been dealing with addiction for 20 years, said: 'I didn't expect it (the strength). I've lost four or five people in the last few months. I have to stop it.'
She also claimed dealers were wrongly calling heroin containing nitasenes 'fentanyl' and selling it for as little as £10 a bag in Birmingham. Some offered multi-purchase deals.
The NCA believes that nitazenes are produced in illegal laboratories in China and often enter the UK by post.
Others have also suggested that their presence in Britain may have increased following the Taliban's crackdown on heroin production.
This halted the flow of the drug from Afghanistan, which previously supplied the bulk of the UK heroin market, forcing criminal gangs to find alternatives.
In July, the Office for Health Improvement and Disparities (OHID) issued a national patient safety alert regarding nitazenes.
While around 40 opioid-related deaths are recorded in England and Wales every week, there was an “increased number of overdoses” on average, especially among heroin users, some of which led to death, the OHID said.
The drug (pictured) was first discovered in Britain from a sample of white powder found in the back of a taxi in Wakefield in April 2021. They are available in powder, tablet and liquid form and can be injected, swallowed and placed under the tongue. , sniffed and evaporated
It added that tests showed nitasenes were the “common cause” behind the overdoses.
Because the substance is often disguised as something else, there is currently little data on the true prevalence of nitasenes in Britain.
But in October, a police raid on a 'sophisticated factory' in Waltham Forest recovered around 150,000 nitazene tablets, the largest ever recovered stash of synthetic opioids. Eleven people were arrested.
The OHID notes that naloxone – the antidote for opioid overdoses – works against nitasenes.
But it must be given 'quickly' as the drug is more likely to cause respiratory arrest because it is so powerful.
Research shows that patients who take too many nitazenes typically need two doses of naloxone to recover, while fentanyl users only need one.
Experts have also previously told MailOnline that it is 'too late' for most before they realize they have taken nitasenes.
Ian Hamilton, an associate professor of addiction at the University of York, said the rise in deaths from nitasenes is “very worrying, but not surprising given how powerful they are.”
He added: 'Unfortunately the demand for opiates has not decreased and it appears that these types of drugs are filling the gap.
“Most people will not be aware that they are taking these types of opiates or how strong they are until it is too late and they experience problems, including overdose.”