Medicare Part D Benefits

Here are 4 things to know about what Medicare Part D covers:

  1. Each Part D plan may have its own unique set of benefits.
  2. The plan’s formulary and tiers will determine which drugs are covered and how much you pay.
  3. Coverage rules can impact how and when you receive your prescription drug coverage.
  4. Your plan may have in-network pharmacies that offer lower out-of-pocket drug costs

Part D plans have different formularies (drug lists), tiers, coverage rules, and networks, which will affect how you get your drugs covered. Make sure you review a plan’s benefit details before enrolling, especially the formulary. The formulary tells you what drugs are covered by a specific plan.

The Part D "donut hole" coverage gap may affect how much you have to pay out-of-pocket to use your Medicare Part D benefits.

Medicare Part D formulary (drug lists) and tiers

Your Part D plan’s formulary and tiers will determine if your prescription drugs are covered and how much you will pay out-of-pocket for those drugs.

A formulary is a drug list that shows which drugs are covered by a plan. You may face higher out-of-pocket costs if you need a medication that is not on your plan’s approved drug list.

Many Part D plan formularies also place prescription drugs into different tiers. Drugs in different tiers will have different costs. Prescription drugs in lower tiers usually have smaller copayments than drugs in higher tiers.

Plan formulary updates

A Part D plan formulary may change from year to year. Insurance providers may change plan benefits as long as the changes follow Medicare guidelines.

If you currently take a covered prescription medication, your Part D plan provider must notify you if any formulary changes will impact your coverage.

Coverage rules

Part D prescription drug plan coverage rules may affect how and when you receive your prescription drugs.

The rules may include:

  • Quantity limits
  • Prior authorization
  • Step therapy

If you or your medical practitioner believes that one of your Part D plan’s coverage rules should be waived, you may request a plan exception. provides more information about your Part D coverage protections.

Quantity limits

Quantity limits are caps on how much prescription medication you can get during a specific time period.

Prior authorization

If a drug requires prior authorization, your medical practitioner must contact your insurance plan and explain that the prescription is medically necessary.

Step therapy

Step therapy is a form of prior authorization. It requires you to try less expensive drugs that are effective for treating your medical condition before you can move up to a more expensive drug. Your plan may require you to try a generic form of medication before it covers a brand-name prescription.

You and your medical practitioner must prove that the generic medication did not work before the insurance company approves the use of a more expensive drug.

Network pharmacies

Part D plans may have contracts with pharmacies in an established plan network. 

If you visit in-network pharmacies, your prescription drug costs may be lower. If you fill a prescription at a non-network pharmacy, your plan may not cover your medication’s cost at all.

Your Part D plan’s network pharmacies may include retail pharmacies, preferred pharmacies, mail-order programs, and 30- or 90-day retail pharmacy programs.

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*You must continue to pay your Medicare Part B premium.

$0 premium plans may not be available in all areas.

The purpose of this communication is the solicitation of insurance. Contact will be made by an insurance agent/producer or insurance company.

This information is not a complete description of benefits. Contact the plan for more information. Limitations, copayments and restrictions may apply. Benefits, premiums and/or member cost-share may change on January 1 of each year. is a website owned and operated by TZ Insurance Solutions LLC. TZ Insurance Solutions LLC is a licensed and certified representative of A Medicare Advantage [HMO, PPO and PFFS] organization and a stand-alone prescription drug plan with a Medicare contract. Enrollment in any plan depends on contract renewal.

TZ Insurance Solutions LLC and the licensed sales agents that may call you are not connected with or endorsed by the U.S. Government or the federal Medicare program. This website does not contain a complete listing of plans available in your service area. For a complete listing please contact 1-800-MEDICARE (TTY users should call (877) 486-2048), 24 hours a day / 7 days a week or consult

Not all plans or products are available in all markets. Additional plans may be available in your service area. For a complete listing please contact 1-800-MEDICARE (TTY users should call 1-877-486-2048), 24 hours a day/7 days a week or consult

Last Updated: 09/12/2017 Accepted