A previous clinical trial found that tamoxifen, taken for five years, reduced the risk of developing invasive breast cancer by about 50% in post-menopausal women who were at increased risk of getting the disease.
Another trial found that five years of raloxifene reduces breast cancer risk in such women by about 38%.
Under the new plans, high risk post-menopausal women could be offered the drugs for a period of five years unless they have a history of thromboembolic disease or endometrial cancer.
More top news
Joshua James, 23, is accused of hurling the three-and-a-half foot reptile at staff at a Wendy's drive-thru in Florida in October.
A team of MPs have battered journalists including ITV News' Alastair Stewart in an annual charity pancake race.
Labour can make a collective decision on whether to back renewal of Britain's nuclear deterrent, the shadow defence secretary said.