Medicare Part D Formularies: How Drug Tiers and Coverage Work

A Medicare Part D formulary is simply a list of prescription drugs covered by a specific Medicare Part D plan or Medicare Advantage plan with prescription drug coverage. Every plan has its own formulary, and no two are exactly alike. If you take prescription medications, the formulary is the single most important factor in choosing a Part D plan. It dictates not only whether your drugs are covered, but exactly how much you will pay for them at the pharmacy counter.

Medicare requires all Part D plans to cover at least two drugs in the most commonly prescribed categories and classes. This ensures that people with various medical conditions have access to the treatments they need. However, plans have significant flexibility in deciding exactly which specific drugs they include on their lists. They can choose to cover a brand-name drug, a generic equivalent, or both. Because formularies vary so widely, a plan that is perfect for your neighbor might be a terrible fit for you, even if you live in the same zip code.

To manage costs, Part D plans organize the drugs on their formularies into different levels, known as "tiers." The tier a drug is placed on determines your out-of-pocket cost. Generally, the lower the tier, the lower your copayment or coinsurance will be.

Most Part D formularies use a five-tier structure:

• Tier 1 (Preferred Generic): These are the lowest-cost generic drugs. They often have very low copayments, sometimes even $0.
• Tier 2 (Generic): These are standard generic drugs that cost slightly more than Tier 1 medications.
• Tier 3 (Preferred Brand): These are brand-name drugs that the plan has negotiated favorable pricing for, and sometimes higher-cost generic drugs.
• Tier 4 (Non-Preferred Drug): These are higher-cost brand-name and generic drugs. You will typically pay a higher copayment or a percentage of the total cost (coinsurance) for these medications.
• Tier 5 (Specialty Tier): These are the most expensive drugs, often used to treat complex conditions like cancer or multiple sclerosis. You will almost always pay a percentage of the cost (coinsurance) for Tier 5 drugs, rather than a flat copayment.

It is crucial to understand that plans can change their formularies from year to year. They can add or remove drugs, or move a drug to a different tier. This is why you must review your plan's Annual Notice of Change (ANOC) every fall. If a medication you rely on is dropped from the formulary or moved to a more expensive tier, you have the right to switch to a different plan during the Annual Enrollment Period.

We see it all the time: people pick a Part D plan based entirely on the monthly premium, only to find out their most expensive medication isn't on the formulary. That is a costly mistake. Your dollars are votes, and you shouldn't hand them over to an insurance company that won't cover the prescriptions you actually need. You have to look past the paper promises and dig into the details. We'll give you straight answers, no surprises, so you can make the right call.

When reviewing a formulary, you also need to look for "utilization management restrictions." These are rules the plan puts in place to control costs and ensure medications are used appropriately. The three most common restrictions are:

• Prior Authorization: You or your doctor must get approval from the plan before they will cover the drug.
• Quantity Limits: The plan will only cover a certain amount of the drug over a specific period (e.g., 30 pills per month).
• Step Therapy: You must try a less expensive drug first before the plan will cover a more expensive one.

If your drug is not on the formulary, or if it has a restriction that your doctor believes is medically inappropriate, you have options. You can ask your doctor to prescribe a similar drug that is on the formulary. If that is not possible, you or your doctor can request an "exception" from the plan. This is a formal request asking the plan to cover a non-formulary drug or to waive a coverage restriction.

Navigating Part D formularies can be tedious, but it is the only way to protect what you've earned and avoid unexpected costs at the pharmacy. Always verify your specific medications against a plan's formulary before enrolling.