Medicare Part D Prescription Drug Plan


  • Medicare Part D plans covers a wide range of prescription drugs.
  • Medicare Part D plans including most drugs in certain protected classes,” like drugs to treat cancer or HIV/AIDs.
  • Medicare Part D plans come with a list of covered drugs (formulary) specific to the plan.
  • Medicare Advantage and Medicare Part D plans place drugs into different levels called “tiers” on their formulary. Drugs in each tier have a different cost. For example, a drug in a lower tier will generally cost you less than a drug in a higher tier.


  • Tier 1—lowest copayment: most generic prescription drugs
  • Tier 2—medium copayment: preferred, brand-name prescription drugs
  • Tier 3—high copayment: brand-name prescription drugs
  • Tier 4—higher copayment: non-preferred, brand-name prescription drugs
  • Tier 5—highest copayment: Specialty tier highest cost prescription drugs


Medicare Part D Formulary Exception

  • Medicare drug plans may have these coverage rules:
    • Opioid pain medication safety checks
    • Prior Authorization
    • Quantity limits
    • Step therapy
    • Part D vaccine coverage
    • Drugs you get in hospital outpatient settings


  • If you or your prescriber believe that one of these coverage rules should be waived, you can ask your plan for an Exception.
  • Your prescriber (doctor) feels you need a higher Tier drug instead of a similar lower Tier drug, your prescriber may ask your plan for a Formulary Exception. Tier reduction to lower your co-pay may also come into play.