The makers of Seroxat, one of the most commonly prescribed anti-depressant drugs on the market, are to withdraw a claim on its patient leaflet saying the drug is not addictive.
The change comes following widespread allegations from patients who say they cannot give up the drug because of severe withdrawal effects.
GlaxoSmithKline, which produces Seroxat, is to write to GPs across the State next week alerting them to the changes in the accompanying patient information, which also includes new details of side effects caused by the drug.
The move may also have implications for thousands of patients in Britain and the US who are taking legal action against the firm over claims that they became addicted to the drug.
Seroxat is a commonly prescribed antidepressant of the SSRI (selective serotonin re-uptake inhibitor) class, to which Prozac also belongs.
While many people say it has changed their lives by lifting them out of depression, some have experienced painful side-effects when they tried to reduce the dose or stop taking it.
The Irish Medicines Board (IMB) yesterday said it had received around 450 cases of adverse reaction to the drug - a substantial number, according to health experts - since a special register was established in the early 1990s.
A spokeswoman for GlaxoSmithKline downplayed the significance of the change in wording and said this kind of information was changed regularly.
She said the decision to withdraw the phrase, "Remember, you cannot become addicted to Seroxat", came as a result of feedback from patients using the drug.
"We have listened to patients. Nothing had changed, we still maintain that it's not addictive, but we're constantly reviewing every adverse event arising from use of the drug," she said.
In a separate development, GlaxoSmithKline is also to withdraw claims on the Seroxat leaflet that the drug works by normalising the levels of serotonin, a chemical linked with brain function. However, doctors say the link between depression and serotonin levels is unproved.
The IMB said the drug's claims "were not consistent with the scientific literature" and requested the changes.
The IMB's actions were partly prompted as a result of complaints by Limerick-based GP, Dr Terry Lynch, into claims surrounding use of the chemical.
Mr Lynch said the changes over serotonin levels and the withdrawal of claims that the drug was not addictive were "enormously significant".
"It's extraordinary that the wording was there in the first place since it was introduced in 1991. I would question how the IMB allowed the wording there in the first place.
"How could something be so certain for 11 years and then be changed? To tell people it normalised your serotonin levels was a serious error," he said.
