'Zombie' drug xylazine found in cannabis THC vapes in UK

People using cannabis THC vapes risk inhaling a very dangerous substance called xylazine, UK experts warn after discovering some confiscated products contained the "zombie" drug.

The sedative, designed to put big animals such as cows and horses to sleep, can be lethal for humans.

It is "alarming" to find it in "even a few" illicit e-cigarettes that many think are pretty harmless, experts say.

It puts people, as well as those who inject or take strong drugs, at risk.

The illegal global xylazine market has so far mostly seen it mixed with strong opioid drugs, such as heroin or fentanyl.

There has been at least one xylazine-related UK death already - and there are fears misuse could grow, as it has in the US.

• BBC Inside Health: On the trail of a new street drug

Dr Caroline Copeland and colleagues from King's College London say new types of illicit xylazine products are now entering the UK market.

As well as risky vapes, they found tablets being sold as codeine and diazepam, or Valium, that contained xylazine.

The researchers contacted all toxicology laboratories in the UK last year to gather evidence.

They also looked at drug-testing results from hauls seized by law enforcement.

The findings are published in the journal Addiction.

Although the numbers found were small - only two THC vapes and a small number of illegally sold pills out of tens of thousands of products - the experts say it is still extremely concerning.

What are cannabis vapes?

• tetrahydrocannabinol (THC) is the main psychoactive constituent of cannabis - and THC vapes are illegal in the UK

• cannabidiol (CBD) is also a component of the cannabis plant but does not give a high - and CBD oil, including in vapes, is legal to sell in the UK

Dr Copeland told BBC News: "People may not realise what they are actually buying.

"They think they are getting a THC vape - but it could contain much more than they expect.

"It's really alarming."

The UK's Advisory Council on the Misuse of Drugs recently recommended to the government xylazine be listed as a Class C drug, putting it in the same category as laughing gas, anabolic steroids and benzodiazepines, which would mean people possessing it could be jailed for two years and those dealing it 14 years.

The health risks are amplified when it is taken with other strong sedatives.

It can cause:

• difficulty breathing

• dangerously low blood pressure

• slowed heart rate

• wounds that can become infected

• addiction and severe withdrawal symptoms

• death

It is not clear what level of harm inhaling it might do.

Some children and teenagers in the UK have needed hospital treatment after they were thought to have used a vape spiked with another illegal drug, Spice.

King's College London Institute of Psychiatry, Psychology and Neuroscience addictions head Prof Sir John Strang, who was not involved in the study, said: "We need to be constantly alert to changes in the nature of the illicit drug market, especially as these changes sometimes bring new health complications or challenges."

A government spokesperson said: "We are aware of the threat from xylazine and are determined to protect people from the threat posed by this drug and other illicit synthetic drugs.

"We will not hesitate to act to keep the public safe. Following advice from the Advisory Council on the Misuse of Drugs (ACMD), we intend to make xylazine a Class C drug."