It's being reported British drug maker GlaxoSmithKline is going to begin slashing hundreds of jobs in the US as the company starts implementing a major cost-saving program.

GSK announced a new restructuring scheme in October to save around 1.6-billion U.S. dollars in annual costs over the next 3-years.

GSK has been struggling with falling sales of its respiratory drugs in the U.S., which is its biggest market.

Respiratory medicine has traditionally been GSK's strongest business.

Sales of its drug Advair have been tumbling in the United States.

Advair has been hit by competition from different drug rivals and an increasing trend by U.S. health insurers to use hardball tactics to get drug makers to cut prices for older products.