1. Part D plans generally include drugs commonly used by dual eligibles: 2019 Publication: [Washington, D.C.] : U.S. Department of Health and Human Services, Office of Inspector General, June 2019 Subject(s): Dual MEDICAID MEDICARE EligibilityFormularies as TopicInsurance CoverageMedicare Part D -- economicsInsurance, Pharmaceutical Services -- economicsMedicaid -- economicsMedicare -- economicsHumansUnited StatesUnited States.Centers for Medicare & Medicaid Services (U.S.)