NDC Properties in RxNorm

Motivation The National Drug Code (NDC) is a universal product identifier for human drugs in the United States. NDCs can be found on drug packaging and are listed on the Food and Drug Administration (FDA) Structured Product Labels (SPLs). NDCs are used by pharmacists for inventory management and for drug information exchange, as well as in claims data. From a clinical perspective, however, NDCs are too detailed (e.g., packaging information) and need to be mapped to clinical drugs or ingredients (e.g., for medication reconciliation). It is therefore not surprising that the most used query from users in the RxNorm Application Program Interface (API) [https://rxnav.nlm.nih.gov/RxNormAPIs.html] is to map NDCs to the corresponding RxNorm concepts. RxNorm currently contains over 200,000 NDCs, most of which come from SPLs and the rest from First Data Bank. However, until recently, the RxNorm API did not expose the properties associated with NDC (extracted from SPLs). The new API function described here now provides this information.