Medicare's Coverage of Purinethol

Medicare Part D covers Purinethol (mercaptopurine), a medication used to treat certain blood cancers and autoimmune conditions, but your out-of-pocket cost depends on which Part D plan you have and which tier the drug sits on. Most plans place Purinethol on a higher tier because it is a specialty medication, which means you will pay more than you would for a generic drug on a lower tier. The actual dollar amount varies by plan — some charge $50 to $100 per month, others charge 25 to 33 percent of the drug's cost after your deductible is met.

Medicare Part B does not cover Purinethol. Part B covers medications given by injection or infusion in a doctor's office or hospital, but Purinethol is an oral tablet taken at home, so it falls under Part D pharmacy coverage instead. If you do not have Part D, you will pay the full retail price, which can be several hundred dollars per month depending on the dose and your pharmacy.

Key Takeaways

  • Purinethol is covered by Medicare Part D as a prescription drug, but most plans place it on a specialty or higher tier, meaning your copay or coinsurance will be substantial.
  • Your actual cost depends on your specific Part D plan, your deductible status, and whether you have reached the coverage gap or catastrophic phase.
  • You can check your plan's formulary (the list of covered drugs) on your plan's website or by calling the plan's customer service number on your insurance card.
  • If your plan does not cover Purinethol or the cost is too high, you may be able to switch to a different Part D plan during the annual enrollment period or request a coverage exception from your current plan.

How Part D Tiers Affect What You Pay

Part D plans organize drugs into tiers, usually four or five levels. Tier 1 drugs (generics) have the lowest copay. Tier 2 drugs (preferred brand-name) cost more. Tier 3 and Tier 4 drugs cost significantly more, and specialty drugs like Purinethol often land on Tier 3 or Tier 4. A Tier 3 copay might be $75 to $150 per month; a Tier 4 copay can be $200 or more, or a percentage of the drug's cost.

Your plan's formulary is the official list of which tier each drug is on. You can find your plan's formulary by logging into your plan's website, calling the customer service number on your insurance card, or visiting Medicare.gov and searching for your plan by name. The formulary also tells you whether your doctor needs to request prior authorization (approval from the plan before you fill the prescription) or whether the plan requires you to try a different drug first.

Deductibles, Coverage Gaps, and Catastrophic Coverage

Most Part D plans have an annual deductible — typically $505 to $560 in 2024, though this amount changes each year. You pay the full price of Purinethol until you meet your deductible. After that, you pay your copay or coinsurance for the drug until your total out-of-pocket spending reaches a certain threshold, usually around $7,050 to $7,550 in 2024.

Once you hit that threshold, you enter the catastrophic coverage phase, where Medicare pays 80 percent of the cost and you pay 20 percent. This phase continues for the rest of the calendar year. If you take Purinethol year-round, you will likely reach catastrophic coverage, which means your monthly cost will drop significantly in the later months of the year.

Checking Your Plan's Coverage Before You Fill

Before you fill a Purinethol prescription, contact your Part D plan directly. Have your prescription handy — your doctor's office can provide the dose and quantity. Call the customer service number on your insurance card and ask: Is Purinethol on the formulary? What tier is it on? What is my copay or coinsurance? Does the plan require prior authorization?

If your plan does not cover Purinethol, or if the cost is prohibitive, ask whether the plan will consider a coverage exception. Some plans will move a drug to a lower tier or waive prior authorization requirements if your doctor documents that you have tried other medications without success or that you have a medical reason to use Purinethol specifically.

Switching Plans or Finding Lower-Cost Options

If your current Part D plan charges too much for Purinethol, you can switch to a different plan during the annual enrollment period, which runs from October 15 to December 7 each year. Use the Medicare Plan Finder tool on Medicare.gov to compare plans side by side. Enter Purinethol and your pharmacy, and the tool will show you the copay or coinsurance for each plan that covers it.

You can also ask your doctor or pharmacist whether a generic version of mercaptopurine is available, or whether a different medication might work for your condition. Some alternatives may be on a lower tier or covered more generously by your plan. Your doctor is the right person to discuss whether switching medications is medically appropriate for you.

Using Manufacturer Copay Cards or Patient information Programs

The manufacturer of Purinethol may offer a copay card or patient information program that reduces your out-of-pocket cost. These programs are separate from Medicare and can work alongside your Part D coverage. Ask your doctor's office or pharmacist whether a copay card is available, or search the manufacturer's website for "patient information" or "copay reduction."

Patient information programs typically require you to meet income limits and provide proof of financial need. If you may have access to, the program may cover part or all of your copay. These programs change frequently, so check directly with the manufacturer or ask your pharmacist to look it up for you.

Frequently Asked Questions

Will Medicare Part B cover Purinethol if my doctor gives it to me in the office?

No. Part B covers drugs administered by a healthcare provider in a clinical setting, but Purinethol is a tablet you take at home, so it is always covered under Part D pharmacy coverage, not Part B. If your doctor wants to supervise your treatment, they can do that during office visits while you take the medication at home.

What if I cannot afford my copay even with catastrophic coverage?

Contact your Part D plan and ask about hardship exceptions or cost-reduction programs. Some plans have emergency copay information for patients with financial hardship. You can also reach out to the manufacturer's patient information program or nonprofit organizations that help cancer patients pay for medications.

Can I use a GoodRx coupon or discount card instead of my Medicare coverage?

You cannot use both at the same time. If a discount card offers a lower price than your Part D copay, you can choose to pay cash and use the discount card, but that payment will not count toward your Part D deductible or out-of-pocket maximum. Discuss this with your pharmacist before you decide.

Does my Part D plan cover Purinethol for all conditions, or only certain ones?

Most plans cover Purinethol for any condition a doctor prescribes it for, but some plans may require prior authorization or may limit coverage to specific diagnoses. Check your plan's formulary or call customer service to confirm what your plan covers for your specific condition.

What happens to my coverage if I switch Part D plans mid-year?

You can only switch Part D plans during the annual enrollment period (October 15 to December 7) or if you have a may have access to life event such as loss of other coverage or a move. If you switch, your deductible and out-of-pocket spending reset with the new plan on January 1.