How to Check Drug Coverage Tiers and Formulary Changes for Medicare Part D

Every January, millions of seniors face a quiet but costly surprise: their monthly pill cost jumps from $10 to $55 overnight. It’s not a mistake. It’s a formulary change. If you’re on Medicare Part D or a private plan with drug coverage, your medications are grouped into tiers that determine how much you pay at the pharmacy. These tiers aren’t set in stone. They change every year-and sometimes mid-year-without warning. Knowing how to check them before you fill your prescription can save you hundreds, even thousands, a year.

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, each with its own price tag. Tier 1 usually has the cheapest generics. Tier 5 often includes expensive specialty drugs like those for diabetes or weight loss. The higher the tier, the more you pay.

In 2023, Medicare Part D plans covered over 53 million people. Every single one of them relies on their plan’s formulary to know what they’ll pay for insulin, blood pressure pills, or cholesterol meds. The problem? The same drug can be in Tier 1 with a $5 copay on one plan and Tier 3 with a $45 copay on another. And if your plan changes the tier mid-year, you’re stuck paying the new price unless you act.

How Tiers Work: 3, 4, or 5 Levels?

Not all plans use the same system. Most have either 3, 4, or 5 tiers. Here’s what you’re likely to see:

• Tier 1: Preferred generics. These are the cheapest. Think metformin, lisinopril, atorvastatin. Copays are often $0-$10.
• Tier 2: Non-preferred generics or lower-cost brand-name drugs. Expect $10-$20.
• Tier 3: Higher-cost brand-name drugs. These are usually older brands without generic alternatives. Copays jump to $30-$60.
• Tier 4: Non-preferred brand-name drugs with alternatives available in lower tiers. Often requires prior authorization. Costs $60-$100.
• Tier 5: Specialty drugs. These include GLP-1 weight loss meds like Wegovy, injectable diabetes drugs, or treatments for rare conditions. Copays can be $150 or more, or you pay a percentage (coinsurance) of the full price.

Why does this matter? In 2023, about 17% of formulary changes involved moving a drug to a higher tier-meaning higher costs for you. A common example: when a new generic version of a brand-name drug hits the market, insurers often move the original brand to Tier 4 or 5 to push patients toward the cheaper version.

How to Check Your Drug’s Tier Right Now

You don’t need to wait for a letter. You can check your drug’s tier today. Here’s how:

1. Find your plan’s website. If you’re on Medicare Part D, go to Medicare.gov and use the Plan Finder tool. If you’re on a private plan like Cigna, Humana, or Excellus BCBS, search for “[Your Plan Name] formulary.”
2. Use their online drug lookup tool. Most plans have a search box where you type in your medication’s name. Enter the exact brand or generic name-don’t use abbreviations.
3. Look for the tier number. It’s usually listed right next to the drug name. Also check for any restrictions: “Prior Authorization Required” or “Step Therapy Required.”
4. Check the cost. The tool will show your copay or coinsurance for that tier. Compare it to last year’s number.

Pro tip: Use GoodRx or SingleCare to compare cash prices too. Sometimes paying cash is cheaper than your copay, especially if your drug moved to a high tier.

What to Do When Your Drug Gets Moved to a Higher Tier

If your medication suddenly costs more, you’re not powerless. Here’s what to do:

• Ask your doctor for an exception. You have the right to request that your plan cover your drug even if it’s not on the formulary-or if it’s in a higher tier. Your doctor fills out a form explaining why you need it. Approval rates range from 55% to 82%, depending on your plan and medical evidence.
• Ask for a therapeutic alternative. Your pharmacist can suggest a similar drug in a lower tier. For example, if your brand-name blood pressure pill moved to Tier 3, ask if a generic version like losartan is an option.
• Request a transition supply. If your plan removes your drug entirely, they must give you at least a 30-day supply while you work on a long-term solution.
• Call customer service. Don’t rely on the website alone. Ask: “Is this change final? When does it take effect? Can I get a temporary exception?”

Many seniors don’t know about exceptions. In a 2023 GoodRx survey, 31% of users said they didn’t understand how to request one. That’s how people end up skipping doses or paying too much.

When Do Formulary Changes Happen?

Most changes happen on January 1st, when new plan years begin. But changes can happen anytime. CMS allows plans to update formularies during the year if:

• A new generic becomes available
• A drug is recalled or has new safety warnings
• A new, more effective drug is approved

By law, your plan must notify you in writing if a change affects a drug you’re taking. But here’s the catch: they only have to send the notice after the change takes effect. So if your insulin cost jumped in February, you might not get the letter until March.

That’s why you need to check your formulary every January-and again every June. Set a calendar reminder. Look up your top 3 medications. Don’t wait for a bill to tell you something changed.

GLP-1 Weight Loss Drugs Are the New Hotspot

In 2023 and 2024, drugs like Wegovy, Ozempic, and Mounjaro became wildly popular. But they’re also extremely expensive. Most plans now put them in Tier 5, with copays over $150. Some plans even require prior authorization or proof of obesity-related health issues before covering them.

According to the Medicare Rights Center, this is the fastest-growing formulary change trend. If you’re on one of these drugs, check your tier every quarter. Plans are still adjusting coverage as new competitors enter the market. In September 2023, FepBlue admitted some 2026 formularies were still showing Wegovy in the wrong tier.

Who Can Help You Navigate This?

You don’t have to figure this out alone.

• Your pharmacist. They see formulary changes daily. Ask them: “Is there a cheaper alternative?”
• SHIP (State Health Insurance Assistance Program). Free, local counselors help seniors with Medicare questions. They helped 1.7 million people in 2022. Find yours at shiptacenter.org.
• Medicare.gov’s 1-800-MEDICARE. Call anytime. They can look up your plan’s current formulary and explain your rights.

UnitedHealthcare and Cigna rank high for formulary clarity. Smaller regional plans? Not so much. If their website is confusing, call them. Don’t guess.

What to Do Before Open Enrollment

November is open enrollment season. This is your chance to switch plans before next year’s changes hit. Here’s how to pick the best one:

• Make a list of all your medications, including dosages.
• Use Medicare’s Plan Finder tool to compare plans side-by-side.
• Look at the “Total Estimated Annual Cost” for each plan-not just the monthly premium.
• Check if your top 3 drugs are in Tier 1 or 2.
• Look for plans with $0 premiums but high drug costs. Sometimes the math doesn’t add up.

Plans with better drug coverage get higher Medicare Star Ratings. 4- and 5-star plans usually have lower tiers for common meds. Don’t just pick the cheapest premium. Pick the plan that covers your pills best.

Final Tip: Don’t Trust Last Year’s Info

Last year, your blood pressure pill cost $12. This year? $52. You didn’t miss a payment. You didn’t change plans. The formulary changed. And if you didn’t check, you paid more.

Medicare Part D formularies aren’t designed to be simple. They’re designed to save insurers money. But you can win. By checking your tiers every January, asking for exceptions, and switching plans if needed, you control your costs-not your insurer.

Your health shouldn’t depend on a paperwork maze. Stay informed. Stay proactive. And never assume your drug’s price is fixed.

Next Steps: What to Do Today

1. Write down the names of all your medications, including doses. 2. Go to your plan’s website or Medicare.gov and search each one. 3. Note the tier and cost for each. 4. Compare this to last year’s costs. 5. If anything increased, call your pharmacist or doctor to ask about alternatives or exceptions. 6. Set a reminder for January 1st and June 1st every year to check again.

Formularies aren’t going away. But you don’t have to be caught off guard. A few minutes each year can keep your out-of-pocket costs from skyrocketing.