There have been 17 non-fatal overdoses linked to drugs containing nitazene in Cork City over the past 10 days.
It is understood that while 12 of the overdoses took place between Wednesday, December 6, and Tuesday, December 12, a further five occurred up to Friday.
On December 8, the HSE issued an “extreme risk” warning after nitazene was linked to eight non-fatal overdoses over the preceding 36 hours.
It followed 57 such incidents over a two-week period in Dublin last month which were also linked to a nitazene-type substance.
Toxicology and autopsy reports of drug users who died in Dublin during that period are also set to be analysed to establish if any fatalities in the capital are linked to the drug.
In a warning on social media on December 8, the HSE said it “has been confirmed through analysis conducted by Forensic Science Ireland that a trace amount of a nitazene-type substance has been identified in a light brown powder associated with Cork City overdoses”.
A statement from the HSE said that “ongoing analysis is being conducted on the sample to identify the exact composition of the substance”.
The HSE has urged people not to experiment with new drugs or new batches being sold on the drugs market in the Cork area.
Garda sources said they are aware of the emergence of the drug among heroin users in the city in recent weeks.
The HSE warns that users of the drug face "a substantial risk of overdose, hospitalisation and death.” Nitazene is a synthetic opioid which was sold more than 60 years ago as a morphine alternative but never approved for the medical market.
It comes in two forms: powder and tablets. The overdoses in Ireland have been linked to the powder variant.
In September, six deaths which had gone to inquest in the North were found to be linked with the presence of nitazene, with the first death having occurred in April 2022.
The HSE has urged people to access the naloxone antidote which is available from addiction services in Cork City, and to avoid using drugs while alone.
Posters have been erected in Cork City as part of a collaboration between health officials and Cork City Council in a bid to make opioid users aware of the circulation of the drug.
Last month, public safety messages were placed on digital road traffic signs across the capital.