Super Heroin "will cause more deaths on city streets"
Fears are growing that the latest lethal drug to hit the streets - known as fentanyl or 'super heroin' - will drive up the death toll in the capital.
Even seasoned addicts are at grave risk from overdosing because of the strength of the drug, even in tiny quantities.
"There is serious concern about fentanyl among health professionals and groups of drug users," said Tony Duffin, director of the Ana Liffey Drugs Project.
"I am concerned there will be further deaths because it is so powerful. There is no safe dose.
A powerful pain killer, it is sold in Irish pharmacies on prescription under a wide variety of different brand names. It costs from €33 to €315 on prescription.
The HSE claim fentanyl can be up to 600 times more potent than Morphine and may be sold as 'designer' fentanyl or 'synthetic' heroin.
To date, five deaths are being investigated here where users are believed to have either smoked or injected the drug, the HSE have said.
"At this time, it seems most likely that fentanyls may be sold in powder form, possibly mixed with heroin or alternatively mixed with caffeine and paracetamol to mimic the effect of heroin," the HSE said.
"Therefore the drug can be snorted, swallowed or prepared for injection. By any route this drug is very dangerous.
"Fentanyl is extremely potent and even the smallest amount can cause overdose.
"It may also be absorbed through the skin.
"The effects of the drug may be indistinguishable from heroin meaning that at this time heroin users are most at risk to unwittingly consume this substance."
Mr Duffin said another drug, Pregabulin, has also been implicated in a number of drug overdose deaths in Dublin.
"It is being sold in tablet form and it is widely available on the streets of Dublin," he said.
"It has emerged in the last two years and has been present in a number of deaths where a cocktail of drugs have been used," he said.