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RXNORM (RXNORM) - Synopsis

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RxNorm, a standardized nomenclature for clinical drugs for humans, is produced by the U.S. National Library of Medicine (NLM). RxNorm is one of a suite of designated standards for use in U.S. Federal Government systems for the electronic exchange of clinical health information.

The goal of RxNorm is to allow various systems using different drug nomenclatures to share data efficiently.

RxNorm provides standard names for clinical drugs (active ingredient + strength + dose form) and for dose forms as administered to a patient. It provides links from clinical drugs, both branded and generic, to their active ingredients, drug components (active ingredient + strength), and related brand names.

RxNorm is intended to cover all prescription medications approved for human use in the United States. Prescription medications from other countries may be included as opportunities allow, a principal consideration being that there be an authoritative source of information about these drugs. Drugs are added to the vocabulary as new products are put on the market. Over-the-counter (OTC) medications will be added and covered, as well, when reliable information about the medications can be found. Drugs are added to the vocabulary as new products are put on the market.

An RxNorm clinical drug name reflects the active ingredients, strengths, and dose form composing that drug. When any of these elements vary, a new RxNorm drug name is created as a separate concept. Thus, an RxNorm name should exist for every strength and dose of every available combination of clinically significant ingredients.

National Drug Codes (NDCs) for specific drug products are linked to that product in RxNorm. RxNorm links its names to many of the drug vocabularies commonly used in pharmacy management and drug interaction software, including those of First Databank, Micromedex®, Gold Standard Alchemy, and Multum. By providing links between these vocabularies, RxNorm can mediate messages between systems not using the same software and vocabulary.

RxNorm includes the following sources:

SABSource Name
ATC Anatomical Therapeutic Chemical Classification System
CVX Vaccines Administered
GS Gold Standard Drug Database
MMSL Multum MediSource Lexicon
MMX Micromedex RED BOOK
MSH Medical Subject Headings (MeSH)
MTHCMSFRF Metathesaurus CMS Formulary Reference File
MTHSPL FDA Structured Product Labels
NDDF FDB MedKnowledge (formerly NDDF Plus)
SNOMEDCT_US US Edition of SNOMED CT (drug information)
USP The United States Pharmacopeia Compendial Nomenclature
VANDF Veterans Health Administration National Drug File

Update Frequency
RxNorm is updated weekly.

Metathesaurus Update Frequency
RxNorm is an updated source in each Metathesaurus release.

Sites Consulted

  1. RxNorm [Internet]. Bethesda (MD): National Library of Medicine (US); 2004 Mar 22 [reviewed 2008 Apr 04; updated 2008 Apr 04; cited 2008 Oct 08]. Available from:; Overview: