Powerful new synthetic opioids detected by Welsh drug testing service

Nation.Cymru staff

Powerful new synthetic opioids have been identified by a Welsh drug testing programme amid warnings that the illicit market is becoming increasingly unpredictable.

Public Health Wales said more than one in three samples submitted to its Welsh Emerging Drug Identification Service (WEDINOS) did not contain the substance the buyer expected.

Its latest annual report, covering April 2025 to March 2026, found 36.6% of community samples where the intended purchase was known did not contain the expected drug.

A further 7.7% contained the intended substance alongside additional psychoactive substances.

For the first time, WEDINOS identified high-potency synthetic opioids known as orphine analogues, including in samples submitted as heroin where they were found alongside veterinary sedatives.

The testing programme identified orphine analogues in 18 samples during the year, while nitazenes – another group of powerful synthetic opioids which have caused concern in recent years – were found in 110.

Public Health Wales said the presence of such substances increased the risk of accidental overdose.

Rick Lines, head of programme for substance misuse at Public Health Wales, said: “Our work at WEDINOS over the past year demonstrates again the continuing volatility of illicit drug markets, and the high level of substitutions within the market that may increase the risk of ill effects and accidental overdose.

“In particular, the growing detection of high potency orphine analogues – some of which have never been seen by WEDINOS before – continues to highlight concerns about the presence of high potency synthetic opiates in the UK drug market.”

The report also identified widespread substitution in illicit products sold as THC, CBD or cannabinoid vapes.

Some 43% of those submitted for testing contained synthetic cannabinoid receptor agonists, known as SCRAs and sometimes referred to as Spice.

Public Health Wales warned that SCRAs used in vapes can cause rapid and severe effects including anxiety, panic, psychosis, hallucinations and seizures.

Benzodiazepines remained the most commonly identified class of psychoactive substances for the eighth consecutive year, with 22 different types detected, compared with 19 the previous year.

Diazepam was the single most commonly identified substance.

Public Health Wales said products bought from online pharmacies can look identical to medication obtained legitimately but may contain substances other than those advertised.

It is advising people to use only medicines obtained through their GP and dispensed by a doctor or high street pharmacy.

Cocaine was the most commonly identified substance among samples submitted from the night-time economy.

Within criminal justice settings, the synthetic cannabinoid MDMB-4en-PINACA was the substance identified most frequently.

Samples

WEDINOS analysed 8,209 samples during 2025-26, up from 8,032 the previous year.

The number of community samples rose from 6,894 to 7,973, while the number of different substances detected increased from 206 to 238.

Samples were received from individuals as well as 103 organisations, services and night-time economy venues.

The median age of people providing samples was 36, although ages ranged from 11 to 88.

WEDINOS accepts drug samples anonymously from across the UK and uses the results to identify emerging substances and provide information about changes in the illicit market.

Mr Lines added: “The public health harm reduction work that WEDINOS is part of, alongside partners from across Wales and the wider UK, is vitally important to enable greater understanding of emerging threats and to reducing the risk of accidental overdose.”

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