What is xylazine? The flesh-eating ‘zombie’ drug linked to 11 deaths in UK

Xylazine, designed as an animal tranquillizer, has been linked to at least 11 deaths in the UK

It was designed to sedate cows, horses and other large animals, but now xylazine, the flesh-eating super-strength ‘zombie’ drug, has been detected in illicit THC vapes, potentially putting recreational cannabis smokers at risk from its deadly effects.

That was one of the “alarming” conclusions of a study by researchers at King’s College London (KCL), which linked the substance to at least 11 deaths in the UK, with fears the tranquiliser could be present in drugs other than opioids such as fentanyl and heroin.

Here we take a look at everything you need to know about the drug:

What is xylazine and how does it work?

Xylazine is approved for veterinary use in the UK and the US and used on many different animal species such as cattle, sheep and horses to calm and facilitate handling, perform diagnostic and surgical procedures, relieve pain, or act as a local anesthetic. It works by slowing down the nervous system and relaxing the muscles.

Sometimes known as ‘tranq’ or tranq dope in the US, Xylazine can dangerously lower an individual’s level of consciousness and lower their heart rate.

In America, it is most frequently used in combination with fentanyl to help better recreate the long-lasting highs experienced by heroin users.

What are its effects?

The drug causes deep sedation and can result in a heavy nod of the user’s head, especially in the first 20-30 minutes after use, depending on the method of administration. People who have taken xylazine can be sedated for several hours.

When injected it is reported to be associated with the development of skin ulcers. Other side effects include dry mouth, drowsiness, hypertension, and tachycardia followed by hypotension and bradycardia, hyperglycemia, reduced heart rate, hypothermia, coma, respiratory depression, and dysrhythmia.

Where did the drug come from?

Xylazine, which is sometimes added to heroin or illicitly manufactured fentanyl (IMF) was first detected in illegal drug markets in Puerto Rico around 2001 and has been found in other countries.

In November 2022, the United States Food and Drug Administration (FDA) issued an alert to healthcare professionals concerning the increased prevalence in illicit drug overdose deaths involving xylazine. It was first linked to deaths in the US mainland in 2006.

File photo: In America, it is most frequently used in combination with fentanyl to help better recreate the long-lasting highs experienced by heroin users (Getty Images)

Since then the detection of xylazine has been reported to mirror the supply in the US, starting in the northeast and then spreading southwards and westward.

Xylazine has now been detected in IMF in 48 states and is reported to have been identified in 23 per cent of IMF powder and 7 per cent of fentanyl tablets seized in 2022.

Arrival in the UK

And now it has arrived in Britain after researchers detected the drug in 16 people, and linked it to 11 deaths since it was first connected to the overdose of 43-year-old Karl Warburton from Solihull, West Midlands, in May 2022.

His case was the first death outside North America and the first in the UK to be linked to xylazine use.

Worryingly, researchers believe the drug has infiltrated a much wider range of illicit substances in the UK – including cocaine, counterfeit codeine and diazepam (Valium) tablets, and even THC cannabis vapes.

Call for action

Experts have called for urgent action to improve testing and wider investment in drug treatment initiatives to avert a US-style drug death crisis.

Senior author Dr Caroline Copeland, from the national programme on substance abuse mortality at KCL, said the findings were cause for alarm.

“Until the 2022 death was reported there was only one lab in the UK that was testing for xylazine. But if you are not looking for something you are not going to find it,” she told The Independent.

Dr Copeland warned some people suffering the chronic skin ulcers caused by the drug limiting blood supply to the extremities – commonly the legs – have had to have limbs amputated.

However British labs are also detecting xylazine in different types of illegal drugs, including cannabis vapes.

Calling for urgent action to avert a crisis, she called for better testing to ensure drug users can identify contaminated supplies.

She said: “There are three simple measures the UK can introduce to prevent the epidemic of xylazine use that has emerged in the USA.

“Cheap xylazine test strips should be made available, healthcare providers need to be aware of the signs that chronic skin ulcers are due to xylazine use, and pathologists and coroners should specifically request toxicology testing for xylazine in relevant cases to understand the true prevalence of the drug.”

The government said it was aware of the threat caused by xylazine and was determined to protect people against it and other illicit synthetic drugs.