HEALTH experts at Public Health Wales are warning of the continuing dangers posed by highly potent synthetic opioids and synthetic cannabinoids.

The warning comes in the latest annual report from the Welsh Emerging Drug Identification Service (WEDINOS).

Between April 2024 and March 2025, WEDINOS received 9,784 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. 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 highlights growing risks from illicit THC vape products. Almost 40 per cent of samples submitted as cannabis vapes actually contained synthetic cannabinoids (SCRAs), which are significantly more potent than cannabis and linked to seizures, cardiovascular complications and sudden episodes of psychosis.

WEDINOS stands for Welsh Emerging Drugs and Identification of Novel Substances service. This harm reduction project is managed by Public Health Wales and is the UK's only nationwide public drug testing service.

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.”

Other statistics from this year’s report include:

  • 9,784 samples received, up from 8,466 in 2023–24.
  • 8,032 were samples analysed.
  • Community submissions increased to 6,894 (from 5,793).
  • 211 distinct substances identified, up from 206 last year.
  • Cocaine was the most commonly identified substance overall, while diazepam was the most common in community settings.
  • Bromazolam, a potent novel benzodiazepine, was frequently found as a substitute for diazepam.
  • 5 per cent of sample providers reported injecting drugs, up from 3.5 per cent last year.
  • Xylazine, a veterinary sedative associated with severe wounds, was detected in heroin samples.

The submission of samples to WEDINOS provides vital evidence for services across Wales, enabling targeted harm reduction advice and supporting both national and international early warning systems.

Those seeking support for drug or alcohol related concerns can contact the Wales Drug and Alcohol Helpline on Freephone 0808 808 2234, by texting DAN to: 81066, or by visiting dan247.org.uk