To amend title XVIII of the Social Security Act to ensure adequate payment amounts for drugs and biologicals under part B of the Medicare Program.

Amends title XVIII (Medicare) of the Social Security Act to revise the average sales price methodology for payment for drugs and biologicals under Medicare part B (Supplementary Medical Insurance Benefits for Aged and Disabled). Directs the Secretary of Health and Human Services to increase the payment amount for a drug or biological to the extent necessary to ensure that it is in no case less than the widely available market price.

Limits the prompt pay discounts included in the calculation of the manufacturer's average sales price to those discounts furnished to physicians. Excludes such discounts from the average sales price calculation for years after 2004.