Health risk from synthetic opioids and cannabinoids highlighted by Welsh drug testing service

Health experts are warning of the dangers posed by highly potent synthetic opioids and synthetic cannabinoids following the publication of a shocking new report carried out by a Welsh drug testing service.

The Welsh Emerging Drug Identification Service, a harm reduction project managed by Public Health Wales, is the UK’s only nationwide public drug testing service.

Between April 2024 and March 2025, the service received 9,784 drug samples – the highest number in its 11-year history and a sign that more people are using the service to reduce harm.

Of these, more than a third (35 per cent) did not contain what people thought they had purchased.

Risks

In many cases, the substances contained high potency synthetic substances that are linked to numerous health risks.

Of particular concern is the continued rise of nitazenes – a group of synthetic opioids that can be hundreds of times stronger than morphine.

WEDINOS identified 13 different nitazenes this year – up from eight last year.

These substances were most commonly found in counterfeit diazepam tablets and in heroin, often without the user’s knowledge.

Nitazenes have been linked to at least 333 drug-related deaths in the UK in 2024.

The report also highlighted growing risks from illicit THC vape products.

Almost 40 per cent of samples submitted as cannabis vapes actually contained synthetic cannabinoids, which are significantly more potent than cannabis and linked to seizures, cardiovascular complications and sudden episodes of psychosis.

Reactions

Professor Rick Lines, Head of Substance Misuse at Public Health Wales, said: “Our report shows that drugs acquired on the illicit market very often contain substances other than what the consumer is intending to purchase, which can increase the risk of adverse reactions.

“WEDINOS shows the vital importance of drug testing services to reduce these harms and the risk of accidental overdose.

“Our service enables members of the public to receive anonymous analysis of substances they have purchased and which they may be considering consuming. It enables informed choice and encourages behaviour change.”

Those seeking support for drug or alcohol related concerns can contact the Wales Drug and Alcohol Helpline on Freephone 0808 808 2234, by emailing [email protected], or by visiting dan247.org.uk