The discounts, agreed to after months of negotiations with drug manufacturers, range between 38% and 79% on the medication’s list price, which is the cost of medication before discounts or rebates are applied — not the price people actually pay for prescriptions.

Medicare spent $50 billion covering the drugs last year and taxpayers are expected to save $6 billion on the new prices, which do not go into effect until 2026. Older adults could save as much as $1.5 billion in total on their medications in out-of-pocket costs. Administration officials released few details about how they arrived at those calculations.

The newly negotiated prices will impact the price of drugs used by millions of older Americans to help manage diabetes, blood cancers and prevent heart failure or blood clots. The drugs include the blood thinners Xarelto and Eliquis and diabetes drugs Jardiance and Januvia.