Aten is the brand name of a medicine called atenolol. Losacar is the brand name of a drug called losartan. Both are used in the management of high blood pressure through different mechanism of action. It would be scientifically incorrect and inappropriate to call atenolol as outdated. It is indicated in patients who suffer from high blood pressure and have concomitant complaints such as palpitations, angina, etc. However, atenolol should be avoided in patients who are suffering from diabetes or are prone to it (with family history of diabetes). In your wife's case, her BP is well controlled with a very small dose of Aten i.e. 25mg. In view of these considerations, it is best to continue with the present medication i.e. Aten 25mg daily.