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 free to use (see terms and conditions). It directly links to RxNorm, the U.S. drug terminology standard and facilitates inclusion of RxNorm identifiers in electronic health records. It allows efficient data entry by logical segmentation of the full names in RxNorm into two parts: drug name + route (e.g. Amoxicillin (Oral Pill)) and strength + dose form (e.g. 250 mb Cap) to avoid big picklists with excessively long names. It excludes drugs from RxNorm that are obsolete or unavailable in the U.S. (based on the RxNorm Current Prescribable Content). There are additional user-friendly features - commonly used synonyms and abbreviations (e.g. HCTZ for hydrochlorothiazide), "tall man" lettering recommended by FDA to avoid medication errors (e.g. ChlorproMAZINE and ChlorproPAMIDE). RxTerms has been evaluated to have good coverage - 99% coverage of both generic and brand names of U.S. most commonly prescribed drugs. RxTerms is used in some production electronic prescribing environments and various third-party products. The Centers for Medicare & Medicaid Services uses RxTerms in a demonstration project of its post-acute care assessment tool (CARE). RxTerms is also used in the NLM’s Personal Health Record (PHR) Project. RxTerms is updated monthly.

• RxTerms documentation and data download: https://mor.nlm.nih.gov/RxTerms/.