RxNorm provides normalized names for clinical drugs and links its names to many of the drug vocabularies commonly used in pharmacy management and drug interaction software, including those of First Databank, Micromedex, MediSpan, Gold Standard Drug Database, and Multum. By providing links between these vocabularies, RxNorm can mediate messages between systems not using the same software and vocabulary.
Concepts are collections of synonyms at a given level of abstraction. Each concept receives an RX_Concept_CUI, which is unique to that concept. An RX_Concept_CUI is essentially the “name” of a concept that computers read and understand. Each drug name carries additional characteristics, including its source, its code (the unique identifier assigned by its source), and its term type. An atom is a drug name plus these additional characteristics. Each atom within a concept receives an atom unique identifier, an RX_Atom_AUI.
Each row in this file represents a single atom, and the RXAtom_AUI value is unique for each row. Essentially, the row is the atom. Because a given concept may include multiple atoms, there may be multiple rows with a given RXConcept_CUI.
RxNorm is creating duplicates of source asserted atoms, which carry multiple meanings. When an atom is duplicated, the original source atom is considered to be a ‘Base’ atom. The duplicate atoms’ strings are created by appending ‘_#N’ to the Base atom string where ‘N’ is a number from 1 to N number of duplicates for this base atom. The duplicate atom’s ‘Term_Type_in_Source_TTY’ will be created by prepending ‘MTH_RXN_’ to the base atom’s term type.