SYNTHETIC drugs and so-called "legal highs" are becoming a major threat in Ireland, causing 11 deaths in just one year.
A major new European report also reveals how the drug overdose rate in Ireland is among the highest in Europe.
The latest findings come from the European Monitoring Centre for Drugs and Drug Addiction and reveal that Ireland now ranks third in terms of drug deaths per one million population.
Ireland recorded 70 drug deaths per million, compared with the European average of 17.
Sweden was ranked fourth with 63 and Finland fifth with 58 deaths per million.
The report describes the use of established drugs such as heroin, cocaine and cannabis as broadly stable or in decline.
But this is undermined by the proliferation of new psychoactive substances across the continent, with their volume, diversity and availability placing authorities under pressure.
More than 80 new chemical drugs were discovered in Europe last year, making a total of almost 250 detected over the past four years.
While several of these drugs that were previously sold as legal highs are now banned in countries like Ireland, including mephedrone (meow meow), new combinations of toxic chemicals are emerging.
Gardai fear that at least 10 young people have died after taking ecstasy-type tablets containing PMMA over the past two years. The substance causes severe agitation, rapid heart rate and high temperatures.
Last week a public alert was issued by the HSE and gardai following tragic deaths linked to pills called Green Apple and Green Rolex.
And yesterday the HSE confirmed that it had been notified of another sudden death in Donegal linked to an ecstasy-like substance known as Double Cross or Double Black.
Simon Lynch (22) was on a life-support machine in hospital last night after his close friend Oisin Crawford (22), right, was found dead at a house party in St Johnston, Co Donegal.
A statement from the HSE, extending "its deepest sympathies to the family and friends of the deceased", said: "The HSE Public Health Department in the North West is again reminding people of the danger of taking substances including an ecstasy like substance known as Double Cross and/or Double Black."
It is important that anyone displaying negative side effects following the use of drugs seek medical help immediately, said a spokeswoman.
The European Monitoring Centre for Drugs and Drug Addiction said that substances mimicking the effects of controlled drugs are increasingly being sold online.
During 2011 and 2012, 42 people in Ireland who entered treatment reported the synthetic substance MDMA (ecstasy) as their primary drug.
Anecdotally, the use of ecstasy and amphetamine-like substances in Ireland has increased, based on the number of adverse events reported by gardai and emergency services.
Meanwhile, deaths from cocaine fell from 66 in 2007 to 23 in 2011. It was the main problem drug for 654 addicts (8.5pc) entering drug treatment in 2012.
The number of new addicts treated for cocaine abuse fell from 329 (11pc) in 2011 to 282 (8pc) in 2012 while there were 391 seizures of cocaine in Ireland in 2012, down from 1,310 in 2008.