Proposed regulations under the Affordable Care Act (ACA) would save states nearly $18 billion on Medicaid prescription drugs in five years, according to estimates released Friday by the Centers for Medicare and Medicaid Services (CMS).

The rule, which is expected to be finalized in 2013, would include several cost-saving measures, according to CMS: aligning Medicaid reimbursement rates for pharmacies to better reflect what they pay for prescription drugs; increasing rebates paid by drug manufacturers participating in state Medicaid programs; and providing rebates for drugs prescribed to patients in a Medicaid managed care organization.

Savings would total $17.7 billion over five years after implementation, according to CMS.

CMS cited Alabama as an example of a state that had already taken similar measures and seen savings of $30 million in one year. The centers noted that Medicaid programs spent $15.8 billion on prescription drugs in 2009.

The proposed rule, which will be formally published in the Federal Register on Feb. 2, is open for public comment until April 2, according to CMS.