The way medications are covered by Medicare depends largely on who is administering them and in what setting they are received by the patient.
Medicare Part B will cover medications that are not normally self-administered such as infusion drugs administered by physicians in an office or institutional setting. It also covers certain vaccines like flu, pneumonia, COVID-19 or Hepatitis B (for certain at-risk groups) and drugs used as a result of an injury or direct exposure to a disease. Some examples of medications covered under Part B are erythropoieten for End Stage Renal Disease and those undergoing chemotherapy treatment for cancer, injections to treat osteoporosis, and immunosuppresive drugs given after an organ transplant. Also, medications used in a Part B covered infusion pump or nebulizer would qualify.
Prescription drugs administered when you are an inpatient in a hospital are covered under Medicare Part A. Part D covers prescription medications and certain vaccines like shingles and RSV.