RxTerms is a drug interface terminology derived from RxNorm for prescription writing or medication history recording (e.g. in e-prescribing systems, PHRs). RxTerms is derived only from the non-proprietary content of RxNorm, which is developed and maintained by the U.S. National Library of Medicine. No fee or license is required to use the RxTerms data. Technical documentation at https://wwwcf.nlm.nih.gov/umlslicense/rxtermApp/rxTermFileStructure.cfm