How to Check Drug Coverage Tiers and Formulary Changes for Senior Medications

Every year on January 1st, hundreds of thousands of seniors wake up to find their monthly medication costs have changed-sometimes dramatically. A pill that cost $10 last year suddenly jumps to $55. No warning. No notice. Just a higher bill at the pharmacy counter. This isn’t a mistake. It’s a formulary change.

What Is a Drug Formulary and Why Does It Matter?

A drug formulary is simply the list of medications your insurance plan covers. But it’s not just a list. It’s organized into tiers, which determine how much you pay out of pocket. Tier 1 drugs are cheap. Tier 5 drugs can cost hundreds per month. The same medication might be in Tier 1 with one plan and Tier 3 with another. That’s why checking your formulary isn’t optional-it’s essential.

Medicare Part D plans, which cover prescription drugs for seniors, are required by law to cover at least two drugs in each therapeutic category. But that doesn’t mean all drugs are treated equally. Insurers use tiers to control costs. Generics go in the lowest tier. Brand-name drugs sit higher. Specialty drugs-like those for diabetes, heart failure, or weight loss-are often stuck in Tier 4 or 5, where you pay a percentage of the price, not a flat copay.

In 2023, about 17% of formulary changes involved moving a drug to a higher tier, usually because a cheaper generic became available. But sometimes, it’s because the drug’s safety profile changed, or the insurer struck a new deal with a manufacturer. The result? You pay more.

How Tiers Work: 3, 4, or 5? Know Your Plan’s Structure

Not all plans use the same tier system. Most fall into one of three structures:

• 3-tier: Tier 1 (generic), Tier 2 (brand-name), Tier 3 (specialty)
• 4-tier: Tier 1 (preferred generic), Tier 2 (non-preferred generic or brand), Tier 3 (non-preferred brand), Tier 4 (specialty)
• 5-tier: Tier 1 (preferred generic), Tier 2 (non-preferred generic), Tier 3 (preferred brand), Tier 4 (non-preferred brand), Tier 5 (specialty)

Here’s what that means in dollars. In 2023, Medicare beneficiaries paid an average of $0-$10 for a Tier 1 generic. Tier 2 generics? Around $15. Tier 3 brand-name drugs? $40-$70. Tier 5? You could be paying $200-$800 per month, depending on the drug.

Take GLP-1 medications like Wegovy or Ozempic. In 2023, many plans moved these into Tier 5-even though they’re used for diabetes and weight loss. One senior in Texas saw her monthly cost for Ozempic jump from $30 to $420 overnight. She didn’t know until she got to the pharmacy.

When Do Formulary Changes Happen?

Most changes happen on January 1st, when new plan years begin. But changes can-and do-happen anytime during the year. The Centers for Medicare & Medicaid Services (CMS) allows plans to update their formularies if:

• A new generic drug hits the market
• A drug is recalled or flagged for safety issues
• A manufacturer changes pricing or availability
• A new drug is approved and the plan wants to include it

Here’s the catch: if your drug is removed or moved to a higher tier, your plan must notify you. But the notice often arrives after the change takes effect. A 2022 survey found that 68% of Medicare beneficiaries didn’t understand their formulary well enough to spot changes before they impacted their wallet.

Some plans send letters. Others email you. A few just update their website. If you don’t check regularly, you won’t know until you’re handed a bill you didn’t expect.

How to Check Your Drug Coverage Tier Right Now

You don’t need a degree in pharmacy to check your formulary. Here’s how to do it in under 15 minutes:

1. Find your plan’s formulary tool. Go to your insurer’s website-whether it’s Humana, Cigna, UnitedHealthcare, or your Medicare Part D plan. Look for "Drug List," "Formulary," or "Find a Drug."
2. Search for each medication you take. Enter the exact name (brand or generic). Don’t guess. Use the spelling on your prescription bottle.
3. Check the tier and cost. You’ll see the tier number and your out-of-pocket cost: copay or coinsurance. Note it down.
4. Compare alternatives. If your drug is in a high tier, see if there’s a similar drug in a lower tier. Ask your pharmacist: "Is there a generic or preferred brand that works the same?"
5. Bookmark the page. Check it again every January and anytime you get a new prescription.

Tools from Cigna, Simply Prescriptions, and Medicare.gov make this easy. Just type in your drug name and you’ll get the tier, cost, and any restrictions like prior authorization.

What If Your Drug Is Moved to a Higher Tier?

Don’t panic. You have options.

Option 1: Ask for a formulary exception. If your drug is medically necessary and no lower-tier alternative works, your doctor can file a request. You’ll need a letter from them explaining why. In 2022, over 1.2 million exceptions were filed. Approval rates ranged from 55% to 82%, depending on the plan and the evidence provided.

Option 2: Switch to a lower-tier drug. Many drugs in the same class work just as well. For example, if your brand-name blood pressure pill moved to Tier 3, ask if lisinopril (a generic) could replace it. Pharmacists are trained to spot these swaps.

Option 3: Use a 30-day transition supply. If your drug was removed or moved, your plan must give you at least one 30-day supply while you work on a long-term solution. Don’t skip filling your prescription-call your insurer right away.

Who Can Help If You’re Confused?

You’re not alone. Formularies are confusing-even for people who’ve been on Medicare for years. That’s why free help exists:

• SHIP (State Health Insurance Assistance Program): Free, local counselors who specialize in Medicare. They helped over 1.7 million seniors in 2022 with formulary questions.
• Your pharmacist: They see your drug history. They know what’s changed. Ask them to check your formulary during your next refill.
• Medicare.gov: The official site lets you compare plans and check formularies side-by-side. Use their Plan Finder tool.

One senior in Ohio called her local SHIP office after her insulin cost doubled. They found she could switch to a different Part D plan that covered her brand-name insulin in Tier 2-saving her $180 a month.

What’s Changing in 2026?

The landscape is shifting fast. In 2026, more than half of the top-selling drugs are expected to be specialty medications-drugs that cost over $670 per month. That means more seniors will face Tier 5 costs.

Also, CMS is testing a simplified 4-tier model for 2025, aiming to reduce confusion. But until then, plans can still use 3, 4, or 5 tiers. And insurers are adding more prior authorizations. In 2023, 41% of non-preferred brand drugs required prior approval-up from 32% in 2020.

And don’t forget: weight loss drugs like Wegovy and Mounjaro are still being reclassified. Some plans still list them incorrectly. If you’re on one, double-check your tier every month.

Final Tip: Make This a Habit

Set a calendar reminder for January 1st. And check your formulary every time you get a new prescription. Even if your plan hasn’t changed, your drugs might have.

Most seniors don’t realize they can ask for help. They don’t know about exceptions. They don’t know their pharmacist can find cheaper alternatives. And they pay the price.

Don’t be one of them. Know your tiers. Know your options. Check before you fill.