All plans must cover a wide range of prescription drugs that people with Medicare take, including most drugs in certain protected classes,” like drugs to treat cancer or HIV/AIDs. Information about a plan’s list of covered drugs (called a “formulary”) isn’t included in this handbook because each plan has its own formulary. Many Medicare drug plans and Medicare health plans with drug coverage place drugs into different levels called “tiers” on their formularies. Drugs in each tier have a different cost. For example, a drug in a lower tier will generally cost you less than a drug in a higher tier.
Most Medicare drug plans (Medicare drug plans and Medicare Advantage Plans with prescription drug coverage) have their own list of what drugs are covered, called a formulary. Plans include both brand-name prescription drugs and generic drug coverage. The formulary includes at least 2 drugs in the most commonly prescribed categories and classes. This helps make sure that people with different medical conditions can get the prescription drugs they need. All Medicare drug plans generally must cover at least 2 drugs per drug category, but plans can choose which drugs covered by Part D they will offer.
The formulary might not include your specific drug. However, in most cases, a similar drug should be available. If you or your prescriber (your doctor or other health care provider who’s legally allowed to write prescriptions) believes none of the drugs on your plan’s formulary will work for your condition, you can ask for an exception.
To lower costs, many plans offering prescription drug coverage place drugs into different “tiers” on their formularies. Each plan can divide its tiers in different ways. Each tier costs a different amount. Generally, a drug in a lower tier will cost you less than a drug in a higher tier.
Here's an example of a Medicare drug plan's tiers (your plan’s tiers may be different):
In some cases, if your drug is in a higher tier and your prescriber (your doctor or other health care provider who’s legally allowed to write prescriptions) thinks you need that drug instead of a similar drug in a lower tier, you or your prescriber can ask your plan for an exception to get a lower coinsurance or copayment for the drug in the higher tier. Plans can change their formularies at any time. Your plan may notify you of any formulary changes that affect drugs you’re taking.
The Food and Drug Administration (FDA) says generic drugs are copies of brand-name drugs and are the same as those brand-name drugs in:
Generic drugs use the same active ingredients as brand-name prescription drugs. Generic drug makers must prove to the FDA that their product works the same way as the brand-name prescription drug. In some cases, there may not be a generic drug the same as the brand-name drug you take, but there may be another generic drug that will work as well for you. Talk to your doctor or other prescriber about your generic drug coverage