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NLM Adds Veterans Health Administration Drug Terminology, NDF-RT, to RxNorm

New Resource Will Enhance Exchange of Drug Information among Computerized Systems

Effective with the RxNorm release on Monday, June 7th, the National Library of Medicine (NLM), the world's largest medical library and an arm of the National Institutes of Health (NIH), will add the US Department of Veterans Affairs, Veterans Health Administration (VHA) National Drug File-Reference Terminology (NDF-RT) as a source vocabulary in its RxNorm database (  RxNorm is a standardized nomenclature for clinical drugs, produced by NLM, which includes and links many source vocabularies that are commonly used in pharmacy management and electronic medical record systems.

The June release of RxNorm, including NDFRT, is available at A UMLS Metathesaurus license is required and can be obtained free of charge from the same site.

NDF-RT is a terminology used to classify drugs according to their clinical properties, including mechanism of action, physiologic effect, therapeutic category, structural class and the established pharmacologic class used by the FDA. It is an extension of the VHA National Drug File (VANDF), another RxNorm source vocabulary. The addition of NDF-RT to RxNorm is a major step towards achieving interoperability of computerized drug information systems.

On January 29, 2010, NLM and VHA signed an agreement enabling NDF-RT data to be included in the RxNorm monthly releases. It will continue to be released as a source in Unified Medical Language System (UMLS) as well.

For more information regarding NDF-RT specifically, please contact Michael Lincoln at Questions about the RxNorm representation of NDF-RT should be sent to