The Medicare prescription drug program, called Medicare Part D, is a voluntary program offering a range of plans with premiums averaging about $33 a month (higher-income enrollees may be subject to a surcharge). Coverage includes prescription drugs, biological products, insulin and certain vaccines. Beneficiaries may choose either standard coverage offered by a prescription drug plan or as part of a Medicare Advantage plan. Many plans also have a deductible, which may be no more than $480 in 2022. Copayments per prescription and coinsurance, typically of 25 percent of the drug’s cost, are required up to an annual threshold above which out of pocket costs are reduced.

However, there is little incentive for a federal retiree with FEHB coverage to join the Medicare prescription drug program. Prescription drug costs already are factored into FEHB premiums, and voluntarily enrolling in a Medicare drug plan could simply amount to paying a second time for coverage you already have. In addition, the Medicare drug benefit is generally considered inferior to what the FEHB provides. There could be situations in which it makes sense to take Part D, though, particularly if you would be eligible for lower rates available to lower-income people.