UDG Healthcare is to sell its drug distribution units in Ireland and Northern Ireland and a unit in its commercial services business to US drug wholesaler McKesson for €407.5m.
McKesson owns LloydsPharmacy, the largest pharmacy chain in the country, with over 93 branches and nearly 1,000 employees.
The healthcare services provider said it would sell its United Drug supply chain and MASTA businesses to focus on its higher-growth, higher-margin international healthcare services businesses.
It said today's move will transform the firm into a more focused international healthcare services business.
It also said it would use proceeds from the sale to reduce debt.
The company also said that its chief executive Liam FitzGerald would retire in March 2016 and named chief operating officer Brendan McAtamney as its new CEO.
Mr FitzGerald has been CEO at the company for the past 15 years and will remain on at UDG as a consultant and director until the end of September
UDG has been facing pressure from the recent consolidation in the global drug wholesaling market as its drug distribution is limited to the island of Ireland.
It has been growing its contract outsourcing and healthcare communications business through acquisitions. The units being sold accounted for more than half of the company's first-half revenue, but their contribution was only about a quarter of its adjusted operating profit.
McKesson said the acquisition follows its recent deal for 281 pharmacies operated by Sainsbury's in the UK.
Both deals were expected to close in the first half of 2016 and add 10-14 cents to adjusted earnings per share in the first 12 months following the acquisitions, the US company said.