ATN	Description	ATV	ATV Example(s)
AMBIGUITY_FLAG	Attribute of atom that has been duplicated; Original atom is "Base" and duplicate atoms are "Duplicate"	"Base" or "Duplicate"	Base Duplicate
RXN_AI†	Attribute of Semantic Clinical Drug (SCD) or Semantic Branded Drug (SBD) atom referring to the active ingredient. The RXCUI of the SCDC responsible for the active ingredient value is also included in curly brackets as of September 2021. The Basis of Strength Substance (BoSS) is the active ingredient or active moiety in a drug product that is measured to provide the product strength. An active ingredient is any component that provides pharmacological activity or other direct effect in the diagnosis, cure, mitigation, treatment, or prevention of disease, or to affect the structure or any function of the body of man or animals.	RXCUI of active ingredient preceded by RXCUI of SCDC responsible for active ingredient value in curly brackets	{329526} 104416 {315951} 227224
RXN_AM‡	Attribute of SCD or SBD atom referring to the active moiety. The RXCUI of the SCDC responsible for the active moiety value is also included in curly brackets as of September 2021. An active moiety is the part of a drug that makes the drug work the way it does. More specifically, the active moiety is the molecule or ion, excluding portions of the molecule that cause the drug to be an ester, salt, or other noncovalent derivative of the molecule, responsible for the physiological or pharmacological action of the drug substance.	RXCUI of active moiety preceded by RXCUI of SCDC responsible for active moiety value in curly brackets	{1665355} 1191 {315951} 4493
RXN_BOSS_FROM	Attribute of SCD or SBD atom referring to the source of the BoSS as either from the active ingredient or the active moiety. The RXCUI of the SCDC responsible for the active ingredient (AI) or active moiety (AM) value is also included in curly brackets as of September 2021.	“AI” or “AM" preceded by RXCUI of SCDC responsible for active ingredient or active moiety value in curly brackets	{329526} AM
RXN_BOSS_STRENGTH_DENOM_UNIT	Attribute of SCDC atom indicating the dosage unit of the strength (e.g. tablets and capsules default to 1).	Unit of measure	MG ML HR
RXN_BOSS_STRENGTH_DENOM_VALUE	Attribute of SCDC atom indicating the number of denominator units for each numerator strength value (e.g. tablets and capsules default 1).	Number	5 1
RXN_BOSS_STRENGTH_NUM_UNIT	Attribute of SCDC indicating the unit of measure for the medicinal product strength.	Unit of measure	MG MEQ ML
RXN_BOSS_STRENGTH_NUM_VALUE	Attribute of SCDC indicating the strength of the BoSS.	Number	25 0.001
NDC	National Drug Code (NDC) value normalized from source-asserted NDC	11-digit, no dashes, HIPAA formatted normalized NDC	58016069367 00781199213
ORIG_CODE	Source code (CODE) of original source atom from which RxNorm concept was created; Found in RXNSAT for some DF and ET atom attributes which were originally from HL7	CODE	HL7T096 U000013
ORIG_SOURCE	Source abbreviation (SAB) of original source atom from which RxNorm concept was created; Found in RXNSAT for some DF and ET atom attributes which were originally from HL7	SAB	NDDF MDDB
RXN_ACTIVATED	Date when an obsolete atom became associated with live source data. In other words, date when an atom was reactivated from SUPPRESS=O to SUPPRESS=N because live source-asserted atoms and relationships to SUPPRESS=N atoms became associated with an obsolete atom. Attribute of BPCK, GPCK, SBD, SCD, SBDC, SCDC, SBDF, SCDF, BN, IN, PIN, or DF atom.	Date	01/28/2010 11/02/2007
RXN_AVAILABLE_STRENGTH	Strength value of SCDG and SBDG atoms for all available strengths of an ingredient at the SCD/SBD level; Also strength value of SCD and SBD atoms	Number followed by a unit of measure	10 MG/ML 0.154 MEQ/ML
RXN_BN_CARDINALITY	Attribute of BN atom that refers to the number of ingredients it contains	"single" or "multi"	single multi
RXN_HUMAN_DRUG	Attribute of BPCK, GPCK, SBD, SCD, or BN atom intended for human use and the country in which the drug is marketed for that purpose; Only applied for US drugs at this time	International Organization for Standardization (ISO) 3166-1-alpha-2 country code	US
RXN_IN_EXPRESSED_FLAG	Attribute of SCDC atom that is expressed as precise ingredient (TTY=PIN); SCDC atom will have RELA=has_precise_ingredient to a TTY=PIN atom in RXNREL	"P"	P
RXN_OBSOLETED	Date when an atom no longer had associations with live source data. More specifically, date when an atom was changed from SUPPRESS=N to SUPPRESS=O because no source-asserted atoms and no relationships to SUPPRESS=N atoms existed. Attribute of BPCK, GPCK, SBD, SCD, SBDC, SCDC, SBDF, SCDF, BN, IN, PIN, or DF atom.	Date	09/14/2005 08/30/2007
RXN_QUALITATIVE_DISTINCTION	Qualitative modifiers used to distinguish between concepts, attributed to SCD and SBD atoms	String	Microencapsulated Sugar-Free
RXN_QUANTITY	Factors of time, measures or strength attributed to SCD and SBD atoms	Number followed by a unit measure; Could be a strength, unit of time, or quantity of dosages	12 HR 120 ACTUAT
RXN_STRENGTH	Strength value of SCDC atoms	Number followed by a unit of measure	250000 UNT 0.00833 MG/HR
RXN_VET_DRUG	Attribute of BPCK, GPCK, SBD, SCD, or BN atom intended for veterinary use and the country in which the drug is marketed for that purpose; Only applied for US drugs at this time	International Organization for Standardization (ISO) 3166-1-alpha-2 country code	US
RXTERM_FORM	Drug application interface-friendly dose form attribute of SCD and SBD atoms	Dose form string	Tab Gel
UMLSAUI**	Unified Medical Language System (UMLS) atom unique identifier (AUI) applied to atom during the most recent UMLS release	UMLS AUI	A15550595 A1537190
UMLSCUI**	Unified Medical Language System (UMLS) concept unique identifier (CUI) applied to atom during the most recent UMLS release	UMLS CUI	C1176718 C1599949

†Previously named RXN_BOSS_AI and attached to SCDC prior to September 2021 release.
‡Previously named RXN_BOSS_AM and attached to SCDC prior to September 2021 release.
**Deleted starting with the RxNorm December 2020 release. Current UMLSAUIs and UMLSCUIs can be obtained directly from the UMLS Metathesaurus.

Last Reviewed: January 3, 2023