rxnorm rxnorm rxnorm is short for medical prescription normalized rxnorm is us-specific terminology in medicine that contains all medications available on the us market. it can also be used in personal health records applications. rxnorm is part of unified medical language system (umls) terminology and is maintained by the united states national library of medicine (nlm). concept types rxnorm distinguishes different types of drug concepts. it has concepts for drug ingredients, clinical drugs or dose forms. coverage rxnorm only includes drugs that are approved in usa. use as of may 2017, nlm provides six apis related to rxnorm. there is also a web application called rxmix that allows users to access the rxnorm apis without writing their own programs. rxnorm web viewer (rxnav)