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RxNorm Reference

Free reference guide: RxNorm Reference

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About RxNorm Reference

The RxNorm Reference is a searchable cheat sheet covering the NLM standard drug nomenclature system used across US healthcare. It includes RxCUI concept identifiers, TTY term types (IN, SCD, SBD, GPCK), dose form vocabulary, and NDC-to-RxCUI mapping so you can quickly cross-reference drug codes.

The reference also documents the complete RxNorm REST API with endpoints for /rxcui lookup, /drugs group queries, /interaction drug interaction checks, /allconcepts retrieval, and RxClass classification queries. Each endpoint shows the URL pattern, query parameters, and expected JSON response structure.

All content is organized into four browsable categories: Basic Concepts, Term Types, NDC/Mapping, and API. Whether you are building an EHR integration, validating pharmacy claims, or studying for a health informatics exam, this tool provides instant offline access with no server calls or account sign-ups.

Key Features

  • Complete RxCUI, TTY, SCD, SBD, and GPCK term type reference with real drug examples
  • NDC-to-RxCUI mapping documentation including 10-digit NDC format breakdown
  • RxNorm REST API endpoint reference with URL patterns and JSON response examples
  • Drug interaction API (/interaction) and RxClass classification API documentation
  • Searchable and filterable by keyword across all categories
  • RRF table reference (RXNCONSO, RXNSAT) for bulk data import workflows
  • Python code examples for programmatic RxNorm API integration
  • Dark mode support with responsive layout for desktop, tablet, and mobile

Frequently Asked Questions

What is an RxCUI and how is it used?

An RxCUI (RxNorm Concept Unique Identifier) is a numeric code that uniquely identifies a drug concept in the RxNorm system. For example, RxCUI 161 represents Acetaminophen as an ingredient. RxCUIs are used in EHR systems, e-prescribing, pharmacy claims, and clinical decision support to ensure consistent drug identification across different vocabulary sources.

What do the RxNorm TTY term types mean?

TTY (Term Type) indicates the level of specificity for a drug concept. IN = Ingredient (e.g., Acetaminophen), SCD = Semantic Clinical Drug (e.g., Acetaminophen 500 MG Oral Tablet), SBD = Semantic Branded Drug (e.g., Tylenol 500 MG Oral Tablet), and BN = Brand Name. The hierarchy goes from general ingredients to specific branded products with strength and dose form.

How do I convert an NDC code to an RxCUI?

Use the RxNorm REST API endpoint GET /rxcui?idtype=NDC&id={ndc_code}. For example, GET /rxcui?idtype=NDC&id=50580-0496-01 returns RxCUI 198440 (Acetaminophen 500 MG Oral Tablet). The API is free, requires no authentication, and supports up to 20 requests per second.

How can I check drug interactions using RxNorm?

The RxNorm Interaction API at /interaction/interaction.json?rxcui={rxcui} returns known interactions for a given drug. For multi-drug checks, use /interaction/list.json?rxcuis={rxcui1}+{rxcui2}. Interaction data is sourced from DrugBank and ONCHigh, and includes severity levels and descriptions.

Is the RxNorm API free to use?

Yes, the RxNorm REST API at rxnav.nlm.nih.gov/REST is completely free and open. No API key or authentication is required. The rate limit is 20 requests per second. For bulk data needs, you can download the full RxNorm release files from download.nlm.nih.gov with a free UMLS license.

What is the difference between SCD and SBD in RxNorm?

SCD (Semantic Clinical Drug) describes a generic drug with ingredient, strength, and dose form, such as "Acetaminophen 500 MG Oral Tablet" (RxCUI: 198440). SBD (Semantic Branded Drug) adds the brand name, such as "Acetaminophen 500 MG Oral Tablet [Tylenol]" (RxCUI: 209387). SCD is used for generic prescribing while SBD maps to specific branded products.

How often is RxNorm updated?

RxNorm provides a full release monthly and weekly update patches. Release files are available in RRF (Rich Release Format) from download.nlm.nih.gov. MySQL load scripts are included for database import. Historical version archives are also available for retrospective analysis.

Can I use this RxNorm reference offline?

Yes. Once the page loads, all reference data is stored in your browser. You can search, filter, and browse the complete RxNorm cheat sheet without any network connection. No data is ever sent to a server, making it suitable for use in clinical environments with restricted internet access.