Public Disclosure of Drug Discounts and Real-Time Beneficiary Drug Cost Act This bill requires the Centers for Medicare & Medicaid Services (CMS) to publish certain payment information regarding pharmacy benefit managers (PBMs) and prescription drugs. Specifically, the CMS must publish certain information, as reported by PBMs, relating to generic dispensing rates, drug discounts and rebates, and payments between PBMs, health plans, and pharmacies, in accordance with specified confidentiality requirements. The bill also provides statutory authority for certain provisions of the CMS rule titled "Modernizing Part D and Medicare Advantage to Lower Drug Prices and Reduce Out-of-Pocket Expenses," published on May 23, 2019. The rule requires, in part, Medicare prescription drug plan sponsors to implement an electronic, real-time benefit tool that is capable of integrating with at least one prescriber's electronic prescribing system or electronic health record. The tool must provide prescribers with patient-specific, real-time formulary and benefit information, including information regarding cost-sharing, formulary alternatives, and utilization management requirements. The rule takes effect January 1, 2021.