> For the complete documentation index, see [llms.txt](https://docs.snomed.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.snomed.org/implementation-guides/drug-model-implementation-guide/content-development/snomed-ct-drug-model.md). # SNOMED CT Drug Model ## The Two-Layer Model The SNOMED CT Drug Model provides a comprehensive framework for representing medicinal products across healthcare systems. It is composed of two complementary components: * the SNOMED CT International Drug Model, which defines medicinal products in a jurisdiction-independent and clinically focused manner * the SNOMED CT Drug Extension Model, which represents real-world medicinal products authorized and available within specific jurisdictions Together, these components support consistent representation of medicines across clinical, operational, and regulatory workflows, while enabling interoperability across systems and countries. ### International Drug Model (Clinical Foundation) The international model provides the clinical definition of medicinal products, focusing on characteristics such as: * active ingredient(s) * dose form * strength It defines a set of concept classes that represent medicines at increasing levels of detail: * Medicinal Product (MP) – ingredient only * Medicinal Product Form (MPF) – ingredient + dose form * Clinical Drug (CD) – ingredient + dose form + strength These concepts are: * independent of brand and packaging * consistent across jurisdictions * used for clinical decision support, prescribing, and analytics Examples: * Product containing amoxicillin (MP) * Product containing amoxicillin in oral capsule dose form (MPF) * Product containing precisely amoxicillin 500 mg oral capsule (CD) ### Drug Extension Model (Real-World Representation) The drug extension model builds on the international model to represent actual medicinal products available in a country, including product identity and packaging. It introduces additional concept classes: * Real Clinical Drug (RCD) – a specific authorized product * Clinical Drug Package (CDP) – a generic packaged form * Real Clinical Drug Package (RPCD) – a specific packaged product These concepts are required for workflows that involve real products rather than abstract clinical definitions, such as: * dispensing and administration * inventory and supply chain management * reimbursement and regulatory processes Examples: * Brand X amoxicillin 500 mg oral capsule (RCD) * Amoxicillin 500 mg oral capsule box of 24 (CDP) * Brand X amoxicillin 500 mg oral capsule box of 24 (RPCD) ## How the Models Work Together The international and extension models form a single, integrated structure, where extension concepts build directly on international concepts. ``` MP → MPF → CD → RCD → RPCD └→ CDP ``` This structure reflects two complementary perspectives: * a clinical perspective, which defines what the medicine is * a real-world perspective, which defines how the medicine is supplied and identified ## A Framework Based on Increasing Specificity The SNOMED CT Drug Model can be understood as a progression from abstract to concrete representations: * MP – What substance is involved? * MPF – In what form is it administered? * CD – What is the precise clinical definition (including strength)? * RCD – Which specific product is used? * RPCD – Which specific packaged product is supplied? In parallel: * CDP represents packaging at a generic level, without reference to a specific product This layered approach allows systems to select the appropriate level of detail depending on the use case. ### Attribute-Based Modeling (Conceptual View) The model is based on a structured set of characteristics that define medicinal products. At a high level: * the international model defines clinical characteristics * the extension model adds product identity and packaging characteristics This separation ensures that: * clinical meaning remains consistent across all products * real-world products can be represented without redefining clinical concepts * systems can move between levels (e.g. from product to ingredient) for aggregation and analysis ## Why This Model Matters By combining a shared international foundation with flexible national extensions, the SNOMED CT Drug Model enables: * consistent representation of medicines across systems * safe and precise clinical workflows * accurate identification of real-world products * interoperability across jurisdictions It allows healthcare systems to represent both: * what a medicine is (clinical definition) * what product is used in practice (real-world product and packaging) ## Summary of Drug Model Levels For clarity, the SNOMED CT drug model distinguishes several levels of abstraction. Each level supports different clinical or administrative workflows. | Concept Level | Description | Example | | --------------------------------- | --------------------------------------------------- | ---------------------------------------------------------- | | MP (Medicinal Product) | Drug defined by active ingredient(s) only | *Product containing amoxicillin* | | MPF (Medicinal Product Form) | Drug defined by ingredient and dose form | *Product containing amoxicillin in oral capsule dose form* | | CD (Clinical Drug) | Drug defined by ingredient, strength, and dose form | *Amoxicillin 500 mg oral capsule* | | RCD (Real Clinical Drug) | Authorized or branded medicinal product | *BrandX amoxicillin 500 mg capsule* | | CDP (Clinical Drug Package) | Generic description of package | *Amoxicillin 500 mg capsule box of 24* | | RPCD (Real Clinical Drug Package) | Actual packaged product available in supply chain | *Brand X amoxicillin 500 mg capsule box of 24* | {% content-ref url="/pages/0gzyXyAp6r2eEGxEoi4v" %} [SNOMED International Drug Model](/implementation-guides/drug-model-implementation-guide/content-development/snomed-ct-drug-model/snomed-international-drug-model.md) {% endcontent-ref %} {% content-ref url="/pages/140xuR9dEoTYerr4XhFZ" %} [SNOMED Drug Extension Model](/implementation-guides/drug-model-implementation-guide/content-development/snomed-ct-drug-model/snomed-drug-extension-model.md) {% endcontent-ref %} Provide Feedback --- # Agent Instructions This documentation is published with GitBook. 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