Overlapping Coverage Between Part B and Part D Drugs

Before 2006, Medicare covered a limited number of outpatient medications. Those that were covered under Part B included drugs administered by physicians in an office or clinic setting, drugs used with durable medical equipment (DME) and drugs specifically named in statute. Since January 1, 2006, Medicare beneficiaries have been able to obtain coverage for most other types of outpatient drugs through Part D Prescription Drug Plans (PDPs) or Medicare Advantage – Prescription Drug (MA-PD) plans. Many drugs, however, can actually be covered under either Part B or Part D under a rather complex set of rules that the Centers for Medicare and Medicaid Services (CMS) has developed.

In most instances, it is clear whether drugs are covered under Part B or Part D. In general, Medicare covers drugs that must be administered by physicians under Part B and those drugs purchased at a pharmacy through Part D. However, one source estimated that about 6,000 products [i.e., unique national drug code (NDC) numbers] could potentially be covered under either Part B or Part D (PCMA/NACDS 2006) and the intended use and practice setting is often far from clear. Since Part D plans are required by CMS to accurately determine whether a drug should be covered under Part B before they can approve a claim, plans often require prior authorization on these crossover medications. These prior authorization requirements can sometimes result in administrative burdens on the part of physicians, pharmacists and health plans.

In an attempt to provide greater clarity regarding the processing of these crossover medication claims, we have listed a few important examples of medications that can be covered under either Medicare Plan or an explanation as to when the drug is covered under Part B or Part D. We have also included some important reminders and updates that took effect as of January 1, 2008.