In most cases, you can only make changes to your Medicare Part D prescription drug coverage during Fall Open Enrollment (October 15 through December 7). Your new coverage begins January 1 of the following year. You can change plans as many times as you need during Fall Open Enrollment, and your last choice takes effect January 1. To avoid enrollment problems, it is usually a good idea to make as few changes as possible.

If you have a Medicare Advantage Plan, you can also change your Part D coverage during the Medicare Advantage Open Enrollment Period (MA OEP), which runs January 1 through March 31 each year. To change your drug coverage during this period, you must disenroll from your Medicare Advantage Plan and join a different Medicare Advantage Plan with prescription drug coverage or Original Medicare with a stand-alone Part D plan. Changes made during the MA OEP will take effect the first of the month following the month you enroll. If you want to keep your Medicare Advantage Plan, you should not use the MA OEP to change drug coverage.

Under certain circumstances, you may be eligible to use a Special Enrollment Period (SEP) to make changes to your Part D coverage. You may have an SEP if one of the following events occurs:

  • You lose creditable coverage through no fault of your own.
  • You make a change to your job-based drug coverage.
  • You move out of your Part D plan’s service area.
  • You disenroll from your Medicare Advantage Plan and enroll in Original Medicare, assuming you joined the MA Plan when you first qualified for Medicare based on age and want to disenroll within the first year.
  • There is a five-star plan in your service area that you would like to join.
  • You have or lose Extra Help.
  • You are admitted into or reside in a qualifying institution.
  • You receive inadequate information about whether your existing prescription drug coverage is creditable.
  • Your Part D plan stops offering coverage, fails to provide benefits on a timely basis, or misled you about what benefits you would get.
  • You enroll or fail to enroll in a Part D plan because of a federal employee’s error.
  • You enroll in an All-inclusive Care for the Elderly (PACE) program.
  • You become eligible for a Special Needs Plan (SNP).

For a full list of SEPs and requirements, please see the Part D Special Enrollment Period (SEP) Chart.

Note: After the first 60 days of the year, a Part D plan can make changes to its formulary. If any of your drugs are removed from the formulary through such a mid-year change, your plan should continue to cover the drug for you until the end of the calendar year unless there are safety issues or there is a generic form of your drug. You do not get an SEP if your plan stops covering a drug you need.

To switch plans, you should usually call 1-800-MEDICARE to enroll in your new plan without disenrolling from your old plan. You should be automatically disenrolled from your previous plan when your new coverage begins. To avoid gaps in coverage, try to enroll at the beginning of an enrollment period.