Drug Manufacturers With OBRA 1990 Rebate Agreements To determine which manufacturers' products are covered by rebate agreements, providers must use the manufacturer portion of the product's National Drug Code (NDC) number. (Manufacturer names can change without notice and should not be used to determine coverage.) The manufacturer, or "labeler," portion of the NDC number is the first section of the NDC number. For example, if the NDC number on the drug package label is 2-55-1, the manufacturer labeler code would be 00002. (Note: Leading zeros have been added to make the NDC Labeler Code a 5-digit number.) The list of manufacturers that have a rebate agreement in place changes regularly. The link below takes you to the CMS website for the most current list of Medicaid drug manufacturers. https://www.medicaid.gov/medicaid/prescription-drugs/medicaid-drug-rebate-program/newreinstated-terminated-labeler-information/index.html