AstraZeneca is cutting nearly a quarter of its U.S. sales force in a second wave of redundancies in as many months as it seeks to reduce costs.

Britain's second biggest drugmaker said on Wednesday it would cut about 1,150 sales representative and management jobs at a cost of between $50 million (31.8 million pounds) and $100 million, charged in the fourth quarter.

Rich Fante, president of AstraZeneca US, said it was a difficult decision to make the reductions, which come on top of 400 job losses announced in October.

The changes we are making, however, will help us deliver better results for our business and, most importantly, continue delivering on our mission of patient health, he said.

Restructuring costs are not included in the company's core earnings measure, it said, so the cuts will not have any impact on its guidance for core earnings per share for 2011.

(Reporting by Paul Sandle, Editing by David Jones)