Medicare Part D covers Glumetza, but only if your plan includes it on its formulary
Glumetza is a brand-name extended-release form of metformin, a diabetes medication. Whether Medicare pays for it depends on your specific Part D plan — not all plans cover it, and those that do often require you to pay a portion of the cost. Some plans may ask you to try a generic metformin first before they will cover Glumetza, a requirement called a step therapy.
Medicare Part B does not cover Glumetza. Part B covers inpatient hospital care, doctor visits, and some outpatient services, but not prescription drugs taken at home. If you take Glumetza, you need Part D coverage (or another drug plan) to have Medicare help pay for it.
Key Takeaways
- Glumetza is covered by Medicare Part D plans, but not all plans include it, and coverage varies by plan and year.
- Your out-of-pocket cost depends on which tier your plan places Glumetza on — typically tier 3 or 4 — and how much you have already spent on drugs that year.
- Many Part D plans require step therapy, meaning you must try generic metformin first and show it did not work before the plan will cover Glumetza.
- You can check whether your specific plan covers Glumetza by reviewing your plan's formulary or calling the plan's customer service number on your insurance card.
- If your plan does not cover Glumetza or the cost is too high, you may be able to switch to a different Part D plan during the annual enrollment period in October and November.
How to learn about your Part D plan covers Glumetza
The first step is to check your plan's formulary, which is the official list of drugs your plan covers. You can find this on your plan's website or by calling the customer service number on your insurance card. When you call, ask directly: "Is Glumetza on my formulary?" and "What tier is it on?" The tier determines how much you pay.
If you do not have your plan documents handy, you can also search Medicare's Plan Finder tool at Medicare.gov. Enter your zip code, select your current plan, and search for Glumetza. The tool will show you whether it is covered and what your cost-sharing amount is. Keep in mind that formularies change each year on January 1, so if you are checking in the fall, you are seeing next year's coverage.
What you will pay if Glumetza is covered
Your cost depends on which tier your plan places Glumetza on. Most plans put brand-name drugs like Glumetza on tier 3 or tier 4, which means you pay a higher percentage of the cost than you would for generic drugs on tier 1 or tier 2. Tier 3 typically costs $35 to $75 per prescription; tier 4 can be $75 to $150 or more, depending on the drug's price and your plan.
Your actual out-of-pocket cost also depends on where you are in the Part D benefit year (January through December). In the early part of the year, you pay your regular copay or coinsurance. Once you and your plan have spent $5,850 combined on covered drugs in 2024 (this amount changes yearly), you enter the coverage gap, where you pay a larger share. After you spend $8,550 out of pocket, you reach catastrophic coverage and pay only a small copay for the rest of the year.
If your plan does not cover Glumetza at all, you can pay cash for it — the retail price is typically $30 to $60 per month for a 30-day supply, though this varies by pharmacy and location. Some manufacturers offer discount programs for people without coverage.
Step therapy and prior authorization requirements
Many Part D plans use step therapy for Glumetza, which means the plan will not cover it unless you have already tried and failed on generic metformin. Your doctor must document that generic metformin did not work for you — either because it did not control your blood sugar or because you had side effects — before the plan will cover Glumetza.
Some plans also require prior authorization, meaning your doctor must contact the plan and get written approval before you fill the prescription. This can add a few days to the process. Ask your doctor's office to handle this step; they are familiar with the paperwork and can often speed it up.
If your plan denies coverage because you have not tried generic metformin first, you have the right to appeal. You can ask your doctor to submit an appeal letter explaining why generic metformin is not appropriate for you — for example, if you have a documented allergy or if you tried it in the past and it caused severe side effects.
What to do if your plan does not cover Glumetza or the cost is too high
If your current plan does not cover Glumetza or places it on a high tier, you have several options. The simplest is to switch to a different Part D plan during the annual enrollment period, which runs from October 15 through December 7 each year. During this window, you can join a new plan or switch plans without penalty.
Before you switch, use Medicare's Plan Finder to compare plans that do cover Glumetza and see which one has the lowest cost for you. Enter Glumetza into the drug search and filter by plans in your area. Look not just at the copay for Glumetza, but also at the plan's monthly premium and how it covers your other drugs, if you take any.
If you cannot wait until October, you may be able to make a change if you have a may have access to life event — for example, if you move to a new state, lose other drug coverage, or become newly may be able to access for Medicare. Call Medicare at 1-800-MEDICARE to ask whether your situation qualifies.
Another option is to ask your doctor whether a generic alternative would work for you. Generic metformin is much cheaper and is covered by all Part D plans. Extended-release metformin is available as a generic under the name metformin ER, which may be less expensive than Glumetza even if both are covered.
How Glumetza differs from generic metformin
Glumetza and generic metformin ER both contain the same active ingredient and work the same way in your body. The main difference is that Glumetza uses a specific delivery system designed to release the drug slowly over time, which some people find easier to tolerate. Generic metformin ER also releases slowly, but the formulation is slightly different.
For most people, generic metformin ER works just as well as Glumetza and costs less. Some people do find that Glumetza causes fewer stomach side effects, but this is individual. If your doctor believes Glumetza is medically necessary for you — not just preferred — they can request an exception from your plan, and the plan may cover it even if step therapy normally applies.
Frequently Asked Questions
Can I get Glumetza without Part D coverage?
Yes. You can pay cash at the pharmacy — the cost is usually $30 to $60 per month. Some pharmacies offer discount programs or price matching. You can also check GoodRx or similar discount sites to compare prices at different pharmacies in your area.
Will Medicare cover Glumetza if my doctor says I need it instead of generic metformin?
Possibly. If your plan requires step therapy but your doctor documents a medical reason why generic metformin will not work for you, your doctor can request a formulary exception. The plan reviews the request and may approve coverage. This process usually takes 5 to 10 business days.
What happens if I switch Part D plans in the middle of the year?
You can only switch plans outside the annual enrollment period if you have a may have access to life event. If you do switch, your new plan's coverage starts on the first day of the following month. Any prescriptions filled under your old plan before the switch are covered by that plan.
Does Medicare Part B ever cover Glumetza?
No. Part B covers drugs given to you in a hospital or doctor's office, not drugs you take at home. Glumetza is a home medication, so it is only covered under Part D.
How do I know if my plan's formulary has changed for next year?
Medicare sends updated formulary information to all Part D members in September or early October. You can also check your plan's website or call customer service. If Glumetza is no longer covered or moved to a higher tier, that is a may have access to event that lets you switch plans outside the normal enrollment period.