Medicare Part D prescription drug coverage often referred to as Part D, is provided and coordinated by Medicare-approved private insurance companies.
Each Medicare Prescription Drug Plan has its own list of covered drugs (called a formulary). Many Medicare drug plans place drugs into different “tiers” on their formularies. Drugs in each tier have a different cost. A Medicare drug plan can make some changes to its formulary during the year within guidelines set by Medicare. If the change involves a drug you’re currently taking, your plan must Provide written notice to you at least 60 days prior to the date the change becomes effective.
Any beneficiary who is eligible for Original Medicare, Part A and/or Part B, and permanently resides in the service area of a Medicare Prescription Drug Plan, can sign-up for Medicare Part D. Medicare Part D coverage is optional, but if you don’t enroll in Part D as soon as you’re eligible, you might pay a late-enrollment penalty if you enroll later.