Medicare Part D

Parts A and B of Medicare do not cover most prescription drugs. However, many people have pre-existing health conditions that require prescription medications for treatment. Medicare Part D is an optional part of Medicare made for patients who need that coverage. Overall, Medicare Part D covers:

  • Prescription drugs
  • Some Medicare Cost Plans
  • Some Fee-for-Service Plans
  • Medical Savings Account plans

What Medications are Covered

The specifics of what drugs are covered under Part D are particular to each plan. Each plan has its own formulary and places medications in different tiers. Lower tier medications are less expensive than higher tier medications. To obtain a specific price and coverage for each drug, contact the plan for its formulary. 


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Limitations on Part D

Medicare Part D does have some limitations. Some plans have coverage rules for certain drugs. For example, certain drugs may require prior authorization and have a limit on how much medication you can receive at a given time. They may also require step therapy, meaning that you must try a similar but cheaper medication before they cover the prescribed drug. Some plans also require drug management programs and pharmacy safety checks for opioids and benzodiazepines to encourage safe use.  

How to Get Part D

Prescription drug coverage can be purchased as an add-on to Original Medicare or incorporated into a Medicare Advantage Plan. 

Buying in Addition to Original Medicare:

  • These plans are sometimes called prescription drug plans (PDPs). You must have Parts A and B to add Part D. You can add Part D when you first sign up for Medicare during the General Enrollment Period from April 1 to June 30, between October 15-December 7, or during Special Enrollment Periods. PDPs can be added to Original Medicare, certain Medicare Cost Plans, some Medicare Private Fee-for-Service plans, and Medicare Medical Savings Account Plan. 

Buying as a part of a MAP:

  • Medicare Advantage Plans or other Medicare health plans, such as those offered through employers and unions, may offer prescription drug coverage as a part of their specific plan. As with Original Medicare, you must have Parts A and B covered by your Medicare Advantage Plan to enroll in Part D. If you are enrolled in a Medicare Advantage Plan and would like to add Part D, the Open Enrollment Period is January 1 – March 31 of each year. 

If you are switching plans, you do not need to cancel your old Medicare drug plan. Simply join another plan during the above-listed enrollment periods. 

Cost of Part D

The exact cost of Part D depends on the plan. Expect to pay a monthly premium in addition to the Part B premium. If you have a Medicare Advantage Plan, your monthly premium may already include the premium for prescription drug coverage. 

The cost of Part D will also depend on your household income. If your income is $87,000 or higher, or you file individually or jointly, you will pay more for your monthly premium. This is true for both Original Medicare and Medicare Advantage Plans. Most often, that extra amount for your monthly premium is subtracted from your Social Security check. 

The cost of the yearly deductible depends on the plan. The yearly deductible is the price you must pay before your drug plan begins to pay. Some drug plans do not have an annual deductible. 

A copayment is the amount you pay for your prescription after the deductible. The amount you pay for copayment or coinsurance depends on the drug’s total cost.