RxNorm is a naming system for generic and branded drugs, and a tool for supporting semantic interoperability between drug terminologies and pharmacy knowledge base systems. The RxNorm terminology is produced by NLM.

RxNorm provides normalized names for clinical drugs and links its names to many of the drug vocabularies commonly used in pharmacy management and drug interaction software. By providing links between these vocabularies, RxNorm can mediate messages between systems not using the same software and vocabulary. The goal is to allow computer systems to communicate drug-related information efficiently and unambiguously. Because RxNorm is built on and derived from other terminologies, it reflects and preserves the meanings, drug names, attributes, and relationships from its sources.

Hospitals, pharmacies, and other organizations use various computer systems to record and process drug information. Because these systems use many different sets of drug names, it can be difficult for one system to communicate with another. Sources format their drug names in many ways.

Although the drug names in this Naproxen example appear different, they have the same meaning at a certain concept level. RxNorm groups these synonyms into one normalized concept: naproxen 250 MG Oral Tablet. This concept has an RXCUI (RxNorm concept unique identifier) of 198013.

RxNorm also maps the Food and Drug Administration (FDA) National Drug Code (NDC). The NDC is a unique 10 or 11-digit, 3-segment numeric identifier assigned to medications in the United States and serves as a universal product identifier for human drugs. By mapping NDC codes in RxNorm, users can access comprehensive drug information from multiple sources within the RxNorm database. Additionally, RxNorm normalizes NDCs to 11-digit, no dashes HIPAA format to ensure consistency and standardization across different drug terminologies, enhancing the interoperability and semantic coherence of drug information.