Wolters Kluwer Health (WKHealth) recently released its RxNorm Cross Reference Files. This is a more userfriendly version of the National Library of Medicine's (NLM) standardized nomenclature for clinical drugs. The new data provide a subset of the fields available in the Unified Medical Language System (UMLS) Metathesaurus for RxNorm and map them to existing WKHealth concepts.
RxNorm has been identified to support the electronic prescribing plans included in the Medicare Modernization Act of 2003. By providing NLM's RxNorm standard drug identifier, it allows health care professionals to transmit messages between systems and map drug concepts between proprietary data sets at a level other than the National Drug Code.
In a comparison of the RxNorm subset of WKHealth and NLM's program, WKHealth's product is updated weekly and monthly. The NLM's RxNorm is currently updated quarterly or monthly. While NLM's UMLS provides mapping to WKHealth's generic drug concepts, WKHealth's RxNorm Cross Reference Files include mapping to WKHealth's drug concepts of Drug Descriptor ID and Drug Name ID. WKHealth's RxNorm Cross Reference Files also include a "variance" flag to identify distinctions with mappings between RxNorm and WKHealth's drug concepts.