Duplicate Discount (340B)

Duplicate discounts are one of the two core prohibited practices in the 340B program. They occur when a covered entity purchases a drug at the 340B discounted price and then bills Medicaid for that same drug in a way that triggers a manufacturer rebate—effectively allowing two discounts on the same drug transaction.

The Medicaid Exclusion File (MEF) is the primary mechanism for preventing duplicate discounts in the fee-for-service (FFS) Medicaid context. Covered entities that bill Medicaid FFS for 340B drugs must be properly designated in OPAIS, which generates their MEF designation and signals to state Medicaid agencies not to request manufacturer rebates on those claims.

Duplicate discount risk is more complex in Medicaid managed care (MCO) settings, where the MEF does not automatically apply and covered entities must work with states and MCOs to establish prevention arrangements. As Medicaid managed care has grown, duplicate discount risk in this channel has become an increasingly significant compliance concern.

Covered entities that carve out Medicaid—meaning they do not dispense 340B drugs to Medicaid FFS patients—eliminate FFS duplicate discount risk entirely. Those that carve in must ensure their MEF designation is accurate and their billing workflows are correctly configured.