Three young men were brought to hospital in a period of two weeks when they suffered heart complaints after taking a head shop drug.
The young men developed inflammation of the heart muscle and lining of the heart last month, after they took the legal-high drug mephedrone, which is widely sold in head shops.
Professor Joe Barry, a senior medic from the Department of Public Health and Primary Care at the Trinity College Centre for Health Sciences, said the patients will survive -- but the effects of the drugs were serious because the head shop drug is "not unlike cocaine".
He told the Tallaght Drugs Task Force in a letter seen by the Herald that the patients showed abnormal electrocardiograms (ECGs) after taking the substance, and the drug poses a huge risk to the heart.
"In two weeks, three young men have been admitted to hospital in Dublin with myopericarditis (inflammation of the heart muscle and lining of the heart). In each case the patients gave a history of ingesting mephedrone." He added: "The inflammations in these cases are expected to resolve but patients were admitted because of abnormal ECGs."
The medical expert said that the wider community must be educated about the serious risks attached to mephedrone.
"It is not surprising that mephedrone is cardiotoxic as it is a stimulant not unlike cocaine. It would be important to inform attenders at services and the wider community of this potential further risk to the heart from mephedrone."
Dr Barry warned that head shops are increasing in number, and they're all selling substances which have similar chemical formulae to illegal drugs like cocaine, LSD, and Ecstacy.
"The products are allegedly legal but they're being sold as bath salts and plant foods. But they're the very same as illegal drugs because they have the same compounds. Some are like LSD, some are like magic mushrooms, some are like cocaine, and others are like Ecstacy."
Meanwhile, Dr Bobby Smyth, Consultant Child and Adolescent psychiatrist with the Drug Treatment Centre Board has warned that new head shop drugs are being developed every month.
He also warned that while the Government works to ban certain substances from the controversial head shops, more new substances will emerge onto the market.
"Everyone's been taken aback by the pace these drugs have come onto the market place. Every month they are changing.
"A couple of months before drugs are added to the [banned] list, in those intervening months other drugs will step into the gap.
"It'll be a game of cat and mouse for the next few years."
Meanwhile, he warned that the absence of adequate tests is presenting problems for parents, staff in hospital accident and emergency departments, probation officers and prison officers.
"Probation officers and prison officers relying on urine drug testing are likely to be caught out if they ask [people if they've taken head shop drugs].
"A and E departments as well. The message is to ask the question. If a person is asked did you take drugs they'll say no, so the question needs to be specific."