NEW YORK (CNNMoney) -- The Trump administration announced several changes for Medicare plans aimed at increasing competition and reducing drug costs for senior citizens, starting in 2019.

The Centers for Medicare and Medicaid Services said Monday it will allow insurers to include certain low-cost generic drugs in their approved lists at any point in the year. Also, the agency hopes to broaden beneficiaries' choice of where they get their medications by clarifying that insurers must give all interested pharmacies an opportunity to participate in their networks.

CMS will also reduce the maximum amount that low-income beneficiaries have to pay for certain medicines, known as biosimilars.