A Medicare Part D Formulary refers to the entire list of prescription drugs covered under a Part D Prescription Drug Plan (PDP). The list is usually divided into groups. These groups are based on your cost under the plan and referred to as tiers.
Example: A Tier 1 drug may have a $0 copay; whereas, a Tier 2 drug may have a $10 copay.
Drug Formularies Vary by Company
When shopping for a PDP, it is important to confirm any prescriptions that you are taking will be covered. All companies will list their formularies on their website. An easier method would be to use the Prescription Drug Plan Finder available at Medicare.gov
A Medicare Part D Formulary Can Change Anytime
Changes to the formulary must adhere to the guidelines outlined by Medicare. If a company changes their Medicare Part D Formulary they must:
Notify you in writing 60 days before the modification
If you request a refill, notify you in writing and provide you with a 60 day supply
Formularies and the Medicare Part D Standard Benefit
Medicare Part D Plans are administered and offered through private insurance companies. The companies must provide Part D coverage which is an actuarial equivalent to the Medicare Part D Standard Benefit as defined by Medicare. The standardization applies to the Medicare Part D Formulary. Meaning, someone much smarter than me has done the math and determined a plan provides equal benefits to the chart below even though the drug costs differ by tier and company.
Medicare Part D Standard Benefits 2016
A Prescription Drug Plan May Have Rules
Check with a Drug Plan Provider regarding specific rules that may apply to their formularies. Some companies may require proof of a medical necessity before covering certain drugs. Companies may also have limits on how much medication you can receive at a single time. There is also something called step therapy that may be required. Under step therapy, you have to try similar drugs that cost less before your plan covers the specific drug prescribed.