A High Court decision yesterday means a penicillin-based medicine cannot be distributed to cattle, sheep and pigs pending the outcome of legal proceedings.
The Irish Medicines Board had claimed the product, Norocillin LA, was a public health risk.
Norbrook Laboratories, which distributes the product, had insisted the risk was negligible.
The company said it had evidence that its suggested withdrawal periods for residues were adequate to ensure public health was protected.
Mr Justice Kelly granted the board's application to lift a stay on the board's October 3rd decision to suspend marketing authorisation for Norocillin LA.
The stay was granted to Norbrook, of Armagh Road, Newry, Co Down, by the High Court on October 22nd when it secured leave to seek an order quashing the board's decision.
The judge found the balance of convenience lay in lifting the stay.
He indicated that, in determining where the balance lay, the public-health concerns outlined by the board outweighed the commercial concerns of Norbrook.
The board had contended Norocillin LA represented an "identifiable" public health risk and said marketing authorisation had also been suspended in the UK from June 2000.