Reducing Drug Prices for Seniors Act.

This bill changes how Medicare Part D plans calculate coinsurance for prescription drugs for seniors. Starting in 2025, plans must base coinsurance amounts on the drug's "net price" (the negotiated price after manufacturer discounts) instead of the drug's "list price" (original manufacturer price), for drugs above the deductible but below the out-of-pocket limit. This directly affects Medicare Part D beneficiaries who pay coinsurance for covered drugs, potentially lowering their costs when discounts are applied. The change applies only to drugs covered under the plan's formulary and subject to coinsurance, excluding certain specific drug categories.