> 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/technical-application/integration-with-local-drug-dictionaries.md). # Integration with Local Drug Dictionaries ## Overview Most countries maintain a national drug dictionary or medicinal product registry, which serves as the authoritative source for: * authorized medicinal products * brand names and manufacturers * packaging and presentation * regulatory and reimbursement information These national dictionaries are typically used operationally in: * prescribing systems * pharmacy and dispensing systems * reimbursement and regulatory workflows To enable interoperability and alignment with SNOMED CT, it is necessary to establish systematic mappings between the national drug dictionary and SNOMED CT drug concepts. In addition, the SNOMED CT drug model is aligned with the ISO IDMP family of standards. As a result, national drug dictionaries that are structured according to IDMP, or that adopt compatible standards, can be mapped more efficiently and consistently to SNOMED CT. This is particularly relevant for key elements such as substances, strengths, and dose forms. For example, the use of dose forms aligned with European Directorate for the Quality of Medicines & HealthCare standard terms facilitates direct or near-direct mapping to SNOMED CT concepts, reducing ambiguity and improving interoperability across systems. ## Alignment with National Drug Data Processes In most jurisdictions, national drug dictionaries are: * maintained by regulatory or national bodies * updated regularly based on product authorizations and withdrawals * structured according to national pharmaceutical standards The integration with SNOMED CT is therefore not a one-time activity, but part of an ongoing synchronization process between: * the national drug dictionary * the SNOMED CT International Edition * the SNOMED CT national extension (if implemented) This process is typically managed by the National Release Center (NRC) or an equivalent authority. ## Mapping Approach Mapping from a national drug dictionary to SNOMED CT is typically performed as a semi-automated, systematic process, rather than manual concept-by-concept mapping. The process generally includes: * mapping atomic elements such as substances, dose forms, and units of measure * deriving structured drug concepts based on combinations of these elements (e.g. ingredient + strength + dose form) * linking national product entries to SNOMED CT concepts at the appropriate level: * Clinical Drug (CD) for clinical definitions * Real Clinical Drug (RCD) for specific products * Real Clinical Drug Package (RPCD) for packaged products This approach ensures consistency and scalability across large national datasets. ## Representation of Mappings Mappings between national drug dictionaries and SNOMED CT may be represented in different ways depending on national infrastructure. ### **Proprietary Mapping Representation** In many countries, mappings are maintained within national systems or databases, for example: * as part of the national drug dictionary * within regulatory or reimbursement systems * in dedicated mapping tables This approach allows tight integration with national workflows but may be less portable across systems. ### **SNOMED CT Reference Set Representation** Alternatively, mappings may be represented using SNOMED CT reference sets (refsets). This approach enables: * alignment with SNOMED CT distribution formats (RF2) * versioning and traceability of mappings * reuse across multiple systems within a country * easier sharing between jurisdictions For national implementations that publish SNOMED CT extensions, representing mappings as refsets is often the preferred approach. ## Level of Mapping National drug dictionaries often contain detailed product information, including: * brand names * manufacturers * packaging Mappings should therefore be established at the appropriate level of the SNOMED CT Drug Model, typically: * CD (Clinical Drug) for clinical equivalence * RCD (Real Clinical Drug) for specific authorized products * RPCD (Real Clinical Drug Package) for packaged products In some cases, mappings may also be required at more abstract levels (e.g. MP) for aggregation or reporting. ## Maintenance and Synchronization Mapping between national drug dictionaries and SNOMED CT must be maintained as part of routine national processes. This includes: * updating mappings when new products are introduced * removing or updating mappings when products are withdrawn * aligning mappings with updates to SNOMED CT releases * ensuring consistency between national data and SNOMED CT content Because both national drug dictionaries and SNOMED CT evolve over time, synchronization is an ongoing process rather than a one-time activity. Provide Feedback --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. 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