By Philippa RoxbyHealth reporter
Getty ImagesThe death of a 43-year-old man is the first in the UK to be linked to the "zombie" drug xylazine, which is prompting overdose warnings in the US.
Normally used as a large-animal tranquiliser but now being found in heroin, it can cause a dangerously low heart rate and large open skin wounds.
UK experts are calling it "a really concerning drug".
They say drug users should be warned it is now present in the UK but there is no safe dose in humans.
'Bought heroin'
Karl Warburton, form Solihull, West Midlands, died in May 2022 at home and had a history of illicit drug use, according to the coroner's report. He had been referred to addiction services on a number of occasions.
An examination of his body detected heroin, fentanyl and cocaine in his system, as well as xylazine.
A report on his death in the Journal of Forensic and Legal Medicine says he was "likely to have bought heroin and not known it was laced with xylazine and fentanyl".
"To the best of our knowledge, this is the first death associated with xylazine use reported in the UK, and even Europe, and indicates the entry of xylazine into the UK drug supply," it adds.
Skin ulcers
Xylazine is used by vets as a powerful sedative but it's not approved for use in humans.
Known as "tranq" or "tranq dope" when cut with heroin and fentanyl by drug dealers, xylazine has been causing huge problems in the US.
If injected directly into someone's bloodstream, it can cause large open skin ulcers to form. These can start to rot and lead to amputation.
It also lowers breathing and heart rate to dangerously low levels, which has led to it being dubbed a "flesh-eating zombie drug".
Xylazine emerged on the illicit drug market in Puerto Rico in the early 2000s and has since been found in the US, mainly in the east, and in Canada.
The US government has called it "an emerging threat" because of its growing role in fatal overdoses across the country - about 7% of the total.
And in some states, the drug was found in more than a quarter of overdoses.
But until now, there has been no sign of xylazine in the UK.
The drug was detected only because the Birmingham lab that carried out tests after the man's death noticed some strange results and identified xylaxine.
Death certificate
"The drug is not included in standard drug screens in the UK, so we don't know how widespread the xylazine problem is," said Dr Caroline Copeland, King's College London lecturer and director of the National Programme on Substance Abuse Deaths.
"We need to find out how that person ended up with it in his system."
Xylazine was listed on the man's death certificate as contributing to his death but there was no way of recording it in the UK drug-deaths database.
The report highlights the need to monitor changes in illicit-drug markets and in emerging drugs.
"There is no safe dose to use", it concludes, because there is an overlap between fatal and non-fatal doses of xylazine reported in people.
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