The Director of the National Centre for Pharmacoeconomics (NCPE) has said that he has concerns about the safety and value for money of Covid-19 anti-viral drugs that the Government plans to purchase at a cost of €90m.

Professor Michael Barry said the NCPE was not involved in assessing or approving the drug for use in Ireland.

He said he had concerns about the safety of Pfizer's Paxlovid, the drug which he said the Government is buying the most of.

Speaking on RTÉ's Claire Byrne Live programme, Prof Barry said there were issues particularly in relation to patients who are receiving other medications, adding, "it is not a clean drug in my view, that means it has side effects like most things".

He also raised concerns about the potential side effects of ritonavir, which forms a part of the Paxlovid treatment and said the NCPE would write to all GPs to alert them to potential issues around prescribing these drugs.

Prof Barry said that he was not questioning the efficacy of the drugs, but he was critical that the clinical trials for Pfizer's Paxlovid have not been published.

"If it were me I would be waiting for clinical trial data to be published, I want to see what I am getting for my money. The other aspect is that these agreements or procurements are binding," Prof Barry said.

He said that at €30 million, the annual budget for new drugs in Ireland is a third of what is being spent on these Covid-19 anti-virals, though he believes that budget will be ring-fenced.

"There is a real question over whether this is going to be value for money or not," Prof Barry said.

Speaking on the same programme, Professor Kingston Mills, Immunologist at Trinity College Dublin, said the evidence was clear that these drugs worked.

He said while the data may not have been published yet, the European Medicines Agency and the US Food and Drug Administration, which has already approved the drug, will have seen it.

He said that the "the EMA don't have to have peer reviewed papers to make a decision on a drug ... they have a very stringent set of rules that they have to follow in terms of regulating a drug or a vaccine".