I have isolated all valid/current RxNorm concepts CONCEPT table and have joined it with the ANCESTORS table in order to find their ingredients. This has worked for the majority of valid concepts. However, there are concepts that could not be mapped into ingredients becase their entries are missing in the ANCESTORS table.
See below 2 missing concepts. Note that they do have ingredients concepts (From RxNav).
CONCEPT_ID RXNORM_CODE RXNORM_NAME -> ING_CODE ING_NAME 46274502 1307662 anhydrous lactose 6211 lactose 46274497 1314368 medronic acid 1358207 medronate
Despite the drugs above have ingredients as per RxNav, they do not have any entries in ANCESTORS table (not as ancestor nor descendant), therefore I cannot find their ingredients. I have 15,000 concepts in the same situation. What am I missing? Any help is appreciated.
Note: Most of these missing RxNorm concepts have concept_class ‘Precise Ingredient’ and ‘Brand Name’