Merck & Co is to cut a further 12,000 - 13,000 jobs by 2013, despite announcing quarterly profits of $US2 billion.
The US drug company is seeking an extra $US1.5 billion in annual cost savings.
The BBC reports the cuts will equate to between 13% - 14% of its current 91,000 global workforce.
Merck previously shed 12,500 positions in 2010, at the same time as it created 6000 new jobs.
The company is continuing to streamline its business after buying Schering Plough, a rival business, for $US41 billion in 2009.
Merck made a net profit of $US2 billion in the three months to 30 June, compared with $US752 million a year earlier, when it was hit by a one-off restructuring charge related to the Schering Plough purchase.
Quarterly revenues were up 7% to $US12.5 billion.
Merck & Co is based in New Jersey.