GSK is to close its manufacturing site in Sligo by 2021, with the loss of 165 jobs.
It has been reported that the company informed its employees of a proposal to close the site.
Approximately 165 employees were told that production would be phased out over the course of three years before decommissioning the site in late-2021.
The company said that demand for the products manufactured at the site had not grown in line with expectations making the current business model unsustainable.
According to the company, a number of alternatives for the Sligo site had been evaluated but were not considered to be feasible.
GSK's other sites in Ireland - Cork, Dungarvan and commercial operations - are not affected by this proposal.