by Linda Hyde, RHIA

Drugs are a major part of healthcare. Whether it is prescription medication for acute or chronic conditions, over the counter drugs for allergies, or vitamins and supplements, many of us have a variety of drugs in our medicine cabinets today.

Manufacturing, packaging, and distributing drug data is a huge operation. The main identification of drug data has been the NDC (National Drug Code). This code is made up in part of an identifier for the manufacturer and a code (assigned by the manufacturer) for the specific drug based on strength, formulation and packaging. To identify a drug for a specific strength and form requires collecting NDC’s for all manufacturers and packaging formats. For example, there are over a 100 NDC codes needed to identify patients who are receiving a 10mg tablet of omeprazole (common medication for esophageal reflux). This becomes very cumbersome to manage many of the applications that support drug information such as pharmacy management systems, quality measures, research, and data analytics.

To address this issue, the National Library of Medicine developed RxNorm. RxNorm is a controlled drug terminology supporting semantic interoperability. It includes prescription and over the counter drugs as well as devices used to administer medications. A unique identifier (RXCUI) is assigned at various levels to support different needs for organizing this data. This identifier is then linked to the NDC codes. Examples of these levels include:

  • Semantic Clinical Drug Component – ingredient + strength (e.g. Omeprazole 10mg)
  • Semantic Clinical Drug Form – ingredient + dose form (e.g. Omeprazole Pill)
  • Semantic Clinical Drug or Branded Drug – ingredient + strength + dose form group (e.g. Prilosec 10MG Delayed Release Oral Capsule)

 

The RxNorm dataset is created by several source terminologies such as Medi-San, Micromedex, CMS Formulary reference, FDA structured product labels, and VA Health Administration Drug files. It is updated regularly and can be downloaded on a weekly, monthly or semiannual basis depending on the applications’ need for current data. An online search function is also available at https://rxnav.nlm.nih.gov/ that includes the capability to download selected data into a csv file.

To explore some of the ways in which RxNorm is being used, stay tuned for RxNorm Part 2.