Reducing Drug Prices for Seniors Act.

This bill changes how Medicare Part D coinsurance is calculated for seniors. Starting in 2026, for drug costs above the deductible but below the out-of-pocket limit, coinsurance will be based on the drug's *net price* (the actual negotiated price after manufacturer discounts) instead of the list price. It directly affects Medicare Part D beneficiaries and prescription drug plans by requiring plans to use the net price when calculating these costs. The net price is defined as the discounted price reported in the Detailed DIR Report, excluding manufacturer discounts. This change aims to reduce out-of-pocket costs for seniors by aligning coinsurance with the lower price paid by the plan.