Medicare Part D Formulary
The list of prescription drugs that a Medicare Part D plan covers, organized into cost tiers.
A Medicare Part D formulary is the list of prescription drugs a particular Part D plan covers. Medicare requires every plan to cover at least two drugs in most therapeutic classes and to include all or substantially all drugs in six 'protected classes' (antidepressants, antipsychotics, anticonvulsants, immunosuppressants, antineoplastics, and antiretrovirals). Drugs are organized into tiers — generics on lower tiers cost less, while brand-name and specialty drugs sit on higher tiers and cost more. Plans can use utilization tools like prior authorization, step therapy, and quantity limits. Formularies can change during the plan year for safety, generic introductions, or FDA decisions; plans must give 30 days' notice or refill at the old level. If a needed drug is not on the formulary, a member can request an exception with a doctor's statement, switch to a covered alternative, or change plans during AEP. Compare formularies before enrolling using Medicare.gov's Plan Finder.
In real life
- A member checks her plan's formulary before refilling and finds her brand-name drug moved to a higher tier.
- A doctor files a formulary exception request for a non-covered drug.
- A retiree picks a Part D plan during AEP after comparing formularies for her three monthly medications.
Also known as
Frequently asked questions about Medicare Part D Formulary
Are all Part D plans' formularies the same?+
No. Each plan has its own list and tiers. Always compare before enrolling.
Can a plan change its formulary during the year?+
Yes, with notice. Members generally get 30 days' notice or an extra refill at the old level.
What if my drug is not covered?+
Ask your plan for a formulary exception, switch to a covered alternative, or change plans during AEP.
Where can I compare formularies?+
Medicare.gov Plan Finder.
Source: medicare.gov