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Drug naming standard for electronic health records enhanced

September 6, 2017

Data contributed by Medi-Span improves utility of drug vocabulary produced by NIH

Update - September 29, 2017
Medi-Span data has been removed from RxNorm at Wolters Kluwer’s request. As of October 2017, Medi-Span data will not be included in the RxNorm or UMLS releases. If you have questions, please contact:

The RxNorm standard clinical drug vocabulary produced by the National Library of Medicine (NLM) now contains more accurate and complete connections between National Drug Codes (NDCs), Generic Product Identifiers (GPIs), and standard names of medications recommended for use in electronic health records (EHRs).

The September 2017 monthly RxNorm release also includes, for the first time, Medi-Span's set of NDCs, GPIs, and brand name drugs. Medi-Span, a provider of drug databases widely used in the health care industry, agreed to release this additional information following many discussions regarding its value in the EHR arena.

Including data from Medi-Span improves RxNorm's quality and usefulness in clinical decision support, interoperability, and research. For example, expanding drug information facilitates observational health data studies that rely on identifying groups of patients who have taken medications in the same therapeutic category.

“This collaboration between NLM and a commercial drug information vendor displays the public and private sector’s commitment to supporting electronic health records by ensuring that health data standards reflect current content,” said NLM Director Patricia Flatley Brennan, RN, PhD.

NDCs are product identifiers for human drugs in the United States assigned by drug manufacturers and packagers. Published on medication labels and packages, they are often used in pharmacy inventory control and in drug dispensing and billing. NDCs indicate the manufacturer, product, and package size. Therefore, two versions of the same drug will have different NDCs if they are packaged in different sizes (25 tablets, 50 tablets, etc.) or are produced by different manufacturers.

Medi-Span’s proprietary GPI is a 14-digit code that defines a drug products’ active ingredient(s), dosage form, strength or concentration, route of administration, and therapeutic use. The GPI can be used for several purposes, such as grouping and identifying drugs and their NDCs by therapeutic use, building formularies, and analyzing medication data.

The RxNorm vocabulary creates standard names and identifiers for the combinations of ingredients, strengths, and dose forms (such as Aspirin 325 MG Oral Tablet) that exist in drugs marketed in the United States. Doctors typically include this information when they write a prescription because they often can’t know the specific product that will be used to fill it. All medication products that contain the same active ingredients, the same strengths, and the same dose forms have the same RxNorm standard name. This standard name is connected to other information in RxNorm that can be used within EHR systems to improve patient safety.

Accurate and complete connections between NDC product codes, GPI, and RxNorm standard names and identifiers have many potential uses within an EHR system. These include improving drug data entry, reducing medication errors, and tracking medication trends.

“NLM appreciates Wolters Kluwer’s contribution of their Medi-Span drug information. This addition helps make the RxNorm standard vocabulary more comprehensive and beneficial for patients, health care providers, and researchers,” said Brennan.


The National Library of Medicine (NLM) is a leader in research in biomedical informatics and data science and the world’s largest biomedical library. NLM conducts and supports research in methods for recording, storing, retrieving, preserving, and communicating health information. NLM creates resources and tools that are used billions of times each year by millions of people to access and analyze molecular biology, biotechnology, toxicology, environmental health, and health services information. Additional information is available at

Last Reviewed: September 29, 2017