The Irish Medicines Board (IMB) has said it was surprised by the speed of the decision by Merck & Co to withdraw the arthritis drug Vioxx last week.
Dr Joan Gilvarry, director of human medicines at the IMB, said what was surprising was that the worldwide withdrawal occurred after a study showed that prolonged use of the drug beyond 18 months could increase the risk of heart attack and stroke.
But the drug could have continued to be provided for short-term use, she said.
"The company made a very fast decision last Thursday to withdraw it immediately. We are not entirely aware of the reasons for their decision . . . We are collecting more information," she told a press briefing in Dublin.
"You don't take a knee-jerk reaction and pull a drug," Dr Gilvarry said, adding that a number of people in Ireland were doing well on the drug, and a number of doctors were concerned about it being withdrawn.
The European Medicines Evaluation Agency met Merck yesterday in the Netherlands to discuss what happened. The agency is now expected to recommend a full review of Cox II inhibitors, the class of drug to which Vioxx belongs.
It is understood that manufacturers of Cox II inhibitors will also be asked to furnish the agency with all long-term research data on their products.
Dr Gilvarry stressed that all regulatory agencies like the IMB across Europe were surprised by the speed of the Vioxx withdrawal. Usually, she said, pharmaceutical companies would discuss clinical trial results with regulatory agencies, and a decision would then be taken on what should occur. However, in this case Merck had decided to voluntarily withdraw the drug.
She stressed that the IMB had been aware for a number of years of reports that the drug and other Cox II inhibitors were linked to a risk of heart complaints. She emphasised that there was no drug without side-effects, and a balance had to be struck between the risk of treating or not treating a condition.
A further example of this was the anti-depressant Seroxat. Thousands of people benefited from it, she said, and one had to consider what depressed patients, some of whom were suicidal, would be given if they were taken off Seroxat.