As mentioned above, Part D coverage can be obtained as a stand-alone or as part of a Medicare Advantage Plan. Part D enrollees typically pay a copayment for their prescription medications. Every Medicare Part D plan has a list of covered prescription drugs referred to as a formulary.
Medicare Part D also has a coverage gap, known as the “doughnut hole.” After Part D coverage had paid a certain amount for prescription drugs, a person may have to bear all of the costs themselves, up to a predetermined annual limit (for 2017, this amount is $3,700). This coverage gap applies to Medicare Advantage Plans and stand-alone Part D plans.