Part D

What Is a Medicare Formulary (Drug List)?

A formulary for Medicare is the list of drugs a given Medicare Part D prescription drug plan or Medicare Advantage Prescription Drug (MA-PD) plan will cover. A Medicare plan formulary details information such as how drugs are covered, their relative costs, limitations and/or restrictions.

A Medicare formulary is the list of prescription drugs that are covered by a particular Medicare Part D or Medicare Advantage plan.

Each plan includes its own formulary that determines which drugs are covered by the plan and how much the drugs cost based on factors such as which tier the drug is classified into.

To compare Medicare Advantage prescription drug plans where you live, you can call to speak with a licensed insurance agent or compare plans online. You can also compare Part D plans online when you visit

We represent carriers such as Humana, UnitedHealthcare®, Anthem Blue Cross and Blue Shield, Aetna, Cigna Healthcare, Wellcare, or Kaiser Permanente.

Compare plans today.

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What is the difference between a drug list and a formulary?

A formulary is another term for a list of drugs a health insurance plan can cover.

The drug formulary of one MA-PD plan or one Part D plan may differ from another plan’s formulary. Medicare drug formularies can feature both generic and name brand drugs.

A Medicare formulary can change throughout the year. Drugs may be added or removed from the market at any time, and/or drugs may be added or removed from a plan’s formulary.

Drugs may also remain for sale on the market but be removed from a plan’s formulary for a variety of reasons. According to the Centers for Medicare & Medicaid Services, a drug might be removed from a formulary if the Food and Drug Administration (FDA) decides the drug is unsafe or if the drug manufacturer decides to remove the drug from the market.

From year to year, covered prescription drugs can be moved to a different cost-sharing tier or experience a change in plan restrictions.

Formularies can feature different tiers of drug costs

Drugs on a Medicare formulary are divided into tiers that determine the cost paid by beneficiaries.

For example, a tier 1 drug might consist of low-cost, generic drugs and require only a small copayment in order to fill a prescription. A tier 4 drug, however, might be a more expensive name brand drug that requires a higher copayment.

The number of drug tiers and the cost breakdown will vary according to each plan.

What does a formulary cover?


All Medicare formularies generally must include coverage for at least two different drugs within most drug categories, and formularies must include all available drugs for the following categories:

  • HIV/AIDS treatments
  • Antidepressants
  • Antipsychotic medications
  • Anticonvulsive medications to treat seizure disorders
  • Immunosuppressants
  • Anticancer drugs not covered by Medicare Part B

Some drugs on a Medicare formulary come with certain types of restrictions, such as:

  • Prior authorization
    Beneficiaries may be required to show that they meet certain criteria for consuming the particular drug.

  • Step therapy
    Beneficiaries must first try a less-expensive form of a drug that has been proven effective before being covered for the more expensive version.

  • Quantity limits
    There may be a restriction on the dosage amount of a drug or the frequency that the prescription may be filled.

  • Opioid safety limits
    Opioids often contain restrictions for coverage, and doctors will usually work with a beneficiary and a pharmacist to determine a safe level of opioid prescription for each patient.

Compare plans today.

Speak with a licensed insurance agent


Compare Medicare Advantage plans where you live

If there are Medicare Advantage prescription drug plan options in your area, you can compare plans online or over the phone to find out if any plans feature a drug formulary that fits your prescription drug coverage needs.

To compare plans where you live, including the formularies for plans that cover prescription drugs, call to speak with a licensed insurance agent today.

We represent carriers such as Humana, UnitedHealthcare®, Anthem Blue Cross and Blue Shield, Aetna, Cigna Healthcare, Wellcare, or Kaiser Permanente.


About the author

Christian Worstell is a senior Medicare and health insurance writer with He is also a licensed health insurance agent. Christian is well-known in the insurance industry for the thousands of educational articles he’s written, helping Americans better understand their health insurance and Medicare coverage.

Christian’s work as a Medicare expert has appeared in several top-tier and trade news outlets including Forbes, MarketWatch, WebMD and Yahoo! Finance.

Christian has written hundreds of articles for that teach Medicare beneficiaries the best practices for navigating Medicare. His articles are read by thousands of older Americans each month. By better understanding their health care coverage, readers may hopefully learn how to limit their out-of-pocket Medicare spending and access quality medical care.

Christian’s passion for his role stems from his desire to make a difference in the senior community. He strongly believes that the more beneficiaries know about their Medicare coverage, the better their overall health and wellness is as a result.

A current resident of Raleigh, Christian is a graduate of Shippensburg University with a bachelor’s degree in journalism.

If you’re a member of the media looking to connect with Christian, please don’t hesitate to email our public relations team at

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