Because FEHBP plans pay well for prescription drugs, adding Medicare D prescription drug coverage would not make sense for most retirees. There are exceptions, particularly people with low incomes and limited assets who will not have to pay Part D premiums or deductibles and will not face a gap in coverage. A second possible exception would be a person enrolled in an FEHBP plan with a weak drug benefit.
Since any participant in any FEHBP plan has "creditable" drug coverage, he/she can enroll in Part D in later years without paying a penalty. Or, if one loses FEHB coverage and within 63 days joins a Medicare drug plan, he/she will not have to pay a penalty.
Medicare D participants generally must be enrolled in a specific drug plan, which in turn will contract with the pharmacies that will comprise their primary network. The administration expects that there will be about twelve drug plan choices available. A web-based Medicare Prescription Drug Finder is available during Open Season.