KEGG DRUG is a comprehensive drug information resource for approved drugs in Japan, USA, and Europe (see New drug approvals) unified based on the chemical structure and/or the chemical component, and associated with therapeutic target, metabolizing enzyme, and other molecular interaction network information. KEGG DRUG contains links to the drug labels (package inserts) of all the marketed drugs in Japan and USA according to their active ingredients.

Each KEGG DRUG entry is identified by the D number distinguishing the chemical structure of chemicals or the chemical component of mixtures. It is associated with the following information (see, for example, D01441).

• Generic names (associated with chemical structures, see details below)
• Representative trade names
• Links to FDA approved drug labels information in DailyMed
• Chemical structure, chemical component, peptide/polyketide sequence
• Drug class defined by KEGG DGROUP
• Therapeutic category, ATC code, chemical group defined by KEGG DGROUP
• Activity, efficacy and indicated diseases
• Target molecules in the context of KEGG pathway maps
• Drug metabolizing enzymes and transporters
• Other interacting molecules such as enzyme/transporter inhibition and induction
• Adverse drug-drug interaction data (collected from the Japanese package inserts)
• History of drug development represented as a KEGG DRUG structure map
• Drug classification information in BRITE hierarchy
• Links to outside databases

KEGG DGROUP is a database for structurally and functionally related groups of drugs, especially from the viewpoint of drug interaction networks. In a similar way that the nodes of KEGG pathway maps are defined by the KEGG Orthology (KO) groups generalizing the information of individual organisms, the nodes of drug interaction networks may be defined by the drug groups generalizing the information of individual drugs. The networks include drug-target interactions, drug metabolism involving as substrates, inducers, and inhibitors, and indirect interactions with enzyme and target genes in terms of polymorphisms and mutations.

Chemical group and drug class
KEGG DGROUP entries are divided into chemical groups and the rest. A chemical group contains the same basic chemical structure with minor differences of salts and hydration states, such as DG00710 for Imatinib. The rest is being categorized by efficacy and other criteria as drug classes, such as DG01918 for Tyrosine kinase inhibitor under Antineoplastic.

For representation of efficacy and therapeutic use, different drug classification systems are maintained as part of the KEGG BRITE functional hierarchies. The first group is based on the established classification systems to which KEGG DRUG entries are manually assigned. The classification may be examined with additional information on targets and metabolizing enzymes as well as marketed products linked to DailyMed, shown in a separate column or an additional hierarchy level.

Category	Classification	Additional info			Remark
Prescription drug	ATC Classification	Target	Enzyme	Product	ATC 2020
	USP drug classification	Target	Enzyme		USP DC 2019
	Therapeutic category of drugs in Japan	Target	Enzyme		JP17 (2016)
OTC drug (Japan)	Classification of Japanese OTC drugs
	Risk category of Japanese OTC drugs
Crude drug (Japan)	TCM drugs in Japan	See: KEGG ENVIRON
	Crude drugs in Japan
Additive (Japan)	Pharmaceutical additives in Japan

The second group consists of additional classifications including those developed by KEGG.

Category	Classification
Prescription drug	Target-based classification of drugs
	Antineoplastics
	Antiinfectives
	Topical steroids potency

Furthermore, the following information is provided.

Category	Information
Prescription drug	New drug approvals in the USA
	New drug approvals in Europe
	New drug approvals in Japan
	New drug approvals in the USA, Europe and Japan
	Drugs listed in the Japanese Pharmacopoeia
OTC drug	Rx-to-OTC switch list in Japan
	Rx-to-OTC switch list in the USA
Other	Pharmacogenomic biomarkers
	Prodrugs

Labels information (in Japanese) of all marketed drugs in Japan is provided through the Japanese version of KEGG DRUG.

Join ATC classification USP drug classification Therapeutic category of drugs Classification of Japanese OTC drugs Risk Category of Japanese OTC drugs and Target Metabolizing enzyme Transporter Structure map

Join Antineoplastics New drug approvals in the USA New drug approvals in Europe New drug approvals in Japan New drug approvals in the USA, Europe and Japan and Target Metabolizing enzyme Transporter Structure map

The KEGG drug interaction database contains known adverse drug-drug interactions associated with contraindications (CI) and precautions (P) extracted from the package inserts (drug labels) of all prescription drugs in Japan. The database currently contains over 200,000 interactions (D number pairs) involving more than 4,000 drugs (D number entries) together with annotation about CYP enzymes, overlapping targets, etc. See also Drug Interaction Checker in KEGG MEDICUS for checking actual drug products.

Many marketed drugs have been developed from lead compounds or existing drugs by introducing chemical structure transformations retaining the core chemical structures. KEGG DRUG structure maps graphically illustrate, in a manner similar to KEGG pathway maps, our knowledge on such drug development. They are in the Drug Development category of the KEGG PATHWAY database.

• KEGG Pathway Maps: Drug Development

The chemical structure of a drug is identified by the standardized generic name, but the names can be different in different countries or organizations. The same structure may be called differently and the same name may mean different structures. To accomodate such differences the generic names are associated with the following codes in parentheses.

• JAN - Japanese Approved Name
• USAN - United States Adopted Name
• NF - National Formulary drug name
• INN - International Nonproprietary Name
• BAN - British Approved Name
• DCF - Dénomination commune française

Specifically, for the drugs in Japan and USA whether they are listed in the pharmacopoeia is denoted by:

• JP17 - Japanese Pharmacopoeia, 17th edition
• USP - United States Pharmacopeia

which also imply the JAN and USAN names, respectively. Furthermore, the drugs in Japan include:

• non-JP - Japanese standards for non-Pharmacopoeial crude drugs

for additional crude drugs.

Selected trade names (TNs) are also given in each KEGG DRUG entry. More names may be found from the outside link to DailyMed, which provides FDA approved labels information of marketed drugs.