Medicare drug plans will cover generic and brand-name drugs. Plans may have rules about what drugs are covered in different drug categories to be sure people with different medical conditions can get the treatment they need.
Most plans will have a formulary, which is a list of drugs covered by the plan. This list must always meet Medicare's requirements, but it can change when plans get new information. Your plan must let you know at least 60 days before a drug you use is removed from the list or if the costs are changing. If your doctor thinks you need a drug that isn't on the list, or if one of your drugs is being removed from the list, you or your doctor can apply for an exception or appeal the decision.
(Source: U.S. Department of Health & Human Services)