Your current insurer, whether employer, union or insurance company, is required to send you a letter by September 30, each year, to let you know whether the coverage you have is “creditable” — or at least as good as Medicare’s. If the answer is yes, you can switch to Part D later without paying a penalty. Keep the letter in a safe place, because you may need it to avoid the penalty if you decide to enroll later. You may still want to compare the cost and coverage of your current plan (including premiums, copayments and covered drugs) to see which offers you the best coverage. Keep in mind, however, that if you drop your current coverage, you may not be able to get it back. If your current coverage is not “creditable,” that is, it is not as good as Medicare’s, you will be subject to an enrollment penalty if you wait until later to enroll in Part D.

If your current coverage is designed to supplement the Part D benefit by subsidizing premiums, deductibles or copays ,it is important to keep in mind that amounts paid by your plan provider will not count as Part D costs that will apply to catastrophic coverage eligibility.

If you are considering giving up current coverage to enroll in Part D, be very careful to check the impact on the rest of your health insurance coverage. Some employers, unions or other insurance providers may disenroll you from all your health care coverage if you disenroll from their drug plan.