Between 25 and 30 people working at Alkermes Athlone factory are to be laid off over the next six months.
Employees at the plan were told the news yesterday and the company said the decision has been made following a review of its operations and an assessment of alternatives.
The pharmaceutical company currently employs over 400 people between its Athlone facility and its headquarters in Dublin.
A consultation process is to begin with employees immediately.
The company has said it anticipates the reduction in employee numbers will be achieved through compulsory redundancy.