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Unified Medical Language System (UMLS)

UMLS Vocabularies

RXNORM (RXNORM) - Metathesaurus Representation

This page lists UMLS Metathesaurus data elements and traces them back to the specific source data that populates them.

Skip to: Atoms, Attributes, Definitions, Relationships, Mappings



RxNorm, a standardized nomenclature for clinical drugs, is produced by the National Library of Medicine. Data files are released monthly and available by download. Within each Metathesaurus cycle, RxNorm is updated multiple times. This document reflects the latest cumulative update. The scope of RxNorm is determined by the combined scope of its source vocabularies which include the following:

Sources Description
ATC_2019_19_09_03 Anatomical Therapeutic Chemical Classification System
CVX_2019_08_09 Vaccines Administered
DRUGBANK5.0_2019_08_05 DrugBank
GS_2019_08_14 Gold Standard Drug Database
MMSL_2019_08_01 Multum MediSource Lexicon
MMX_2019_08_12 Micromedex RED BOOK
MTHCMSFRF_2014_19_09_03 Metathesaurus CMS Formulary Reference File
MTHSPL_2019_08_27 Metathesaurus FDA Structured Product Labels
NDDF_2019_08_14 FDB MedKnowledge
RXNORM_19AA_190903F RxNorm Vocabulary
USP_2019_08_19 USP Compendial Nomenclature
VANDF_2019_07_31 Veterans Health Administration National Drug File

Note: Selected portions of MSH and SNOMEDCT are included in the RxNorm release files, however, they are not processed as part of RxNorm for the Metathesaurus except in assigning RXCUI and RXAUI attributes. All MSH or SNOMEDCT data in the Metathesaurus comes directly from that source's data files. This document describes how the RxNorm release files (RXN*RRF) are processed for representation in the UMLS Metathesaurus.  It does not cover processing of individual source vocabularies for inclusion in RxNorm. 

Summary of Changes

New attribute name(s) (ATN) | Source(s):


Source Provided Files:

RXNORM data files are released monthly and available by download.

File Name Description
RXNCONSO.RRF Concept and source information.
RXNDOC.RRF Abbreviated values.
RXNREL.RRF Relationship information, including synonymy
RXNSAB.RRF Source information.
RXNSAT.RRF Attribute information.
RXNSTY.RRF Semantic type information.
RXNATOMARCHIVE.RRF Archive data. Not used.
RXNCUICHANGES.RRF CUI changes. Not used.


  • SDUI: RXNCONSO.SDUI (Currently always blank).

Atoms (MRCONSO):

Term Type

Term types are extracted from field 13 of RXNCONSO.RRF.


For many RxNorm and subsource termtypes, the suppressibility value can be either "O" or "E". For all others, the value is "N". Suppressibility values are extracted from field 17 of RXNCONSO.RRF.

In addition, source NDC attributes may have SUPPRESS="O" or "Y".

Attributes (MRSAT):

All attribute names and their values are extracted from field 9 and 11 of RXNSAT.RRF except for RXCUI and RXAUI which are created using RXNCONSO.RRF.

Definitions (MRDEF):

There are no DEFINITIONS in RXNORM or subsources.

Relationships (MRREL):

All relationships are extracted from field 4 (REL) and field 8 (RELA) of RXNREL.RRF

For detailed information on relationships, see RxNorm documentation

Mappings (MRMAP):

There are no mappings present in RxNorm.