Each Medicare prescription drug plan has it’s own list of covered drugs called a formulary. All formularies are similar because they are based on the same federal guidelines, however they may not include the exact same medications. The federal government requires the plans to include most of the types of drugs used by Medicare beneficiaries. The difference in the drug formularies will be important to you because you will want to be certain that the prescription drugs you take will be on the plan’s list you are planning to enroll in. We break it all down here.