Health Language Blog

RxNorm: Addressing Medication Information Exchange

Posted on 08/24/16

Part Three of our Terminology Standards series introduced LOINC as the standard of choice for exchangemedications.jpg of laboratory and clinical information. This fourth blog introduces RxNorm as the foundation for accurate exchange of medication and prescription information.

Health information exchange is a multifaceted undertaking that encompasses the introduction and adoption of a variety of industry standards to support interoperability. Just as LOINC addresses data exchange for laboratory information, RxNorm provides the foundation for sharing medication information.

Most industry professionals agree that medication terminology is one of the most complex domains in healthcare today. RxNorm is the standard of choice due to its straightforward design and comprehensive framework, which supports various levels of granularity.


RxNorm was created in 2001 by the National Library of Medicine (NLM)—the organization that owns and maintains the standard today. NLM oversees maintenance and provides regular updates of the standard both weekly (delta files) and monthly (full update).


Encompassing all prescription medication available in the U.S., RxNorm supports the granular representation of drugs needed for clinical practice. As such, its use is mandated by regulatory initiatives such as Meaningful Use for quality reporting and interoperability. It is also a HIPAA standard for the transmission of pharmaceutical information.

RxNorm is compiled from 14 source terminologies. It maintains relationships to the originating terminology systems and retains National Drug Codes (NDC) codes when available from the Food and Drug Administration. Source terminologies include:

  • National Drug Files Reference Terminology (NDF-RT)
  • First Data Bank
  • Medi-Span Drug Database
  • Micromedex
  • Multum
  • Alchemy
  • National Drug Codes (NDC)
  • Unique Ingredient Identifiers (UNII)

RxNorm is powerful because it contains information at various levels of detail and is used for many purposes. For instance, information is obtained at such levels of granularity as medication ingredients, strength, and dose. The standard accomplishes this by assigning term types to each of the terminologies that help organize the data. The term types are well defined and describe the type of information required for a concept to be considered. For instance, IN would be the term type indicating the ingredient level. As such, the only information found in a concept with the term type IN would be the active ingredient in a medication.

In terms of limitations, RxNorm does not provide package-level detail, mechanism of action, adverse effects, or contraindications. Other pharmaceutical terminologies are also available in the public domain including:

  • NDF-RT—maintained by the Veterans Administration and modeled similar to RxNorm while adding more detail in areas such as drug class, mechanism of action, and others.
  • NDC—a granular terminology that is required on all pharmacy claims. There are three segments of every NDC code: the labeler, product, and package codes. Its intended use is in inventory management and tracking.
  • UNII codes—restricted to cataloging unique ingredients found in the pharmacy world.

These additional pharmaceutical terminologies are proprietary and built around different functions. They are not required for the transmission of data for interoperability or quality reporting because they are not readily available as a low-cost option, do not always meet the definition of a controlled vocabulary, and are not all compatible with NDC.

Many of the systems found in a healthcare organization utilize different standard pharmaceutical terminologies. Because RxNorm contains links or relationships to those terminologies, it serves as a bridge that makes exchanging and aggregating information from those systems simple and efficient.

Next up in this series, we will take a closer look at some of the administrative standards required for comprehensive analytics across the continuum of care.


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Topics: Standard terminologies, RxNorm, data normalization

About the Author

Celeste Adams is the Clinical Application Analyst with the Health Language Professional Services team. She provides mapping and translation services related to RxNorm, Medi-Span, and other terminologies. Celeste specializes in data normalization for drug projects, and offers consulting and analysis on mapping and translation of client local terminology. With over 20 years of experience in pharmacy, she provides valuable insight and knowledge for Health Language data normalization customers. Most recently, Celeste was involved with a team of clinical experts in providing mapping analysis and data normalization for the U.S. Department of Defense (DoD) as part of its interoperability initiative. Celeste is skilled in developing and delivering application end training to clients, and provides subject matter expertise support for all clients.