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Drug Identifiers

The KEGG DRUG D number is an identifier to distinguish drugs as chemical substances, which is used to integrate approved drugs in Japan, USA and Europe. The D numbers are linked to drug classifications, such as WHO's ATC classification. In KEGG MEDICUS all drug products in the USA (and in Japan in the Japanese version) are given D numbers and organized in the following hierarchy.
Drug classification (ATC code, etc.)
Chemical substance (KEGG DG number and D number)
Drug label (DailyMed setId)
Drug product (NDC)

KEGG D number
A KEGG identifier consisting of the prefix D followed by a five-digit number, representing the chemical structure (or the chemical component of a mixture). See KEGG DRUG database for more details.
(Example) D01441 Imatinib mesylate (Gleevec)

KEGG DG number
A KEGG identifier consisting of the prefix DG followed by a five-digit number, representing the chemical group of essentialy the same active ingredients with minor differences of salts and hydration states, as well as other types of drug groups. See KEGG DGROUP database for more details.
(Example) DG00710 Imatinib

ATC code
Alphanumeric codes of WHO's Anatomical Therapeutic Chemical Classification, which is a five-level classification system. In KEGG MEDICUS the lowest code is assiened to each drug product.
(Example) ATC code L01EA01 for imatinib
L01EA BCR-ABL tyrosine kinase inhibitors
L01EA01 Imatinib

DailyMed setId
A unique identifier for each FDA drug label (package insert) in the DailyMed database.
Consisting of 36 characters including four hyphens.
(Example) 211ef2da-2868-4a77-8055-1cb2cd78e24b GLEEVEC (Novartis)

NDC (National Drug Code)
A unique three-segment number for each drug product in the USA.
Consisting of the labeler code, the product code and the package code.
(Product example) 0078-0401 GLEEVEC
(Package example) 0078-0401-34 GLEEVEC 90 TABLET in 1 BOTTLE

Note that only the first two segments of the NDC code are used in KEGG MEDICUS.

Last updated: March 3, 2023