If you are eligible for Medicare coverage, you are also eligible for the Medicare drug benefit (Part D). You must be enrolled in Medicare Part A and/or Part B to enroll in Part D.
Medicare drug coverage is only available through private plans. If you have Medicare Part A and/or Part B and you do not have other drug coverage (creditable coverage), you should enroll in a Part D plan. This is true even if you do not currently take any prescription drugs. If you delay enrollment in Part D for any amount of time and find that you need drug coverage later, you will incur a premium penalty.
Note: If you are enrolled in Medicaid and become eligible for the Medicare drug benefit, you will usually be automatically enrolled in a Medicare Part D plan and pay no premium for it. If you are in Medicaid and do not want the Medicare drug benefit, call your local Medicaid office.