Introduction

Concepts in a Medicinal Product terminology can be divided into two types:

• those concepts whose representation is abstract but which can be understood and used internationally (with sufficient language support); these are described generically using their internationally recognised constituent parts, which are:  
  • active ingredient substance(s) and basis of strength substances described using their international non-proprietary names (INNs) whenever possible
  • active ingredient strength(s), described using international standards and principles such as the RTO<PQ> datatype (the ratio of physical quantities - see International Organization for Standards. Health informatics — Harmonized data types for information interchange ISO 32090:2011) and/or UCUM units of measure or their equivalent, which in SNOMED CT is accomplished by using specific attributes for each of the numerator and denominator values and units each which can be valued with a SNOMED CT concept
  • pharmacopoeial/internationally defined dose forms
  • pharmacopoeial/internationally defined units of presentation (when appropriate)
• those concepts which describe real or actual products available for clinical use whose representation can only be fully described and understood within a jurisdiction, as they are governed by the regulations of that jurisdiction and produced by authorisation of a medicines regulatory agency responsible for that jurisdiction. This includes:
  • authorised product names (which may be brand or trademarked names); a brand name in one jurisdiction may relate to a different product than the same brand name used in another jurisdiction – although medicines regulatory agencies are trying to reduce this because of the safety issues it raises
  • proprietary dose forms including those describing a timing component  (e.g. "caplets", "24-hour prolonged release tablets")
  • additional characteristics in the product name such as
    • inclusion or exclusion of particular excipients with various roles ("strawberry flavour", "sugar-free")
    • target population groups ("for children")
    • indication for use ("cough and cold")
  • packaging information
    • pack size
    • container description

SNOMED CT International Release contains concepts of the first type; those whose representation is both understandable internationally and whose use has international applicability (e.g. in support of medication information in international patient summaries, or for international pharmacovigilance). But clinical care within member nations requires both the first and the second type of representation for medicinal products; therefore concepts of the second type have to be authored in the extension belonging to that nation (or organisation).  

Purpose

This document depicts an extension concept model to describe the real or actual medicinal products (sometimes described as "branded products") available for use in a particular member nation.  The model is compatible with the international core model for Medicinal Products.  This compatibility means that, when classified using the appropriate tooling, the correct classification results should be achieved with concepts being fully defined wherever possible.  This document should therefore be read alongside the SNOMED CT Medicinal Product Model Specification which describes the classes of concepts present in the international release.

This document is a model specification, and as such it does not describe in any detail the rules and processes to be adopted for population of a national terminology; some general principles are given, but exact processes are not.  These, and the terming guidelines for creation of fully specified names and additional description terms for the concepts that populate the additional model classes will need to be authored by national extensions, mindful of their own language, culture and practice considerations.  These descriptive terms may contain more information than that of the definitional attributes described in this specification: for example, some products may contain excipient information in their name - "without preservative" or "orange flavour", or target population information "for children"; all of this can be be reflected in the fully specified name for the relevant concept but would not be included in the value of the "product name attribute" - see section 10.1 below.  In addition, national extensions may wish to author a range of synonym terms, including user interface terms, to support direct implementation.  National extensions may wish to include the abstract class fully specified name within or after the fully specified name for the associated real product (for example including the full generic Clinical Drug name (either FSN or PT) in the Real Clinical Drug name: "AMOCAPS 250mg Freds Pharmaceuticals (amoxicillin 250mg oral capsules)").   However, when additional concepts for core classes of the international model (MP, MPF (if required) and CD) are authored in a national extension, the naming guidelines for the international release should be followed, for the FSN in particular.

In this document, as generally, the words 'package' and 'pack' are synonymous; 'package' is the preferred term in the documentation, although 'pack' may be used especially when short text is required.

General principles for authoring SNOMED CT extension content can be found at 5.4.1 General Authoring Principles

Scope

The scope of this model as documented is limited to medicinal products (pharmaceutical and biological); products that represent blood products, foods, additives, and complementary medicines (including homoeopathic products) are currently out of scope. Currently, vaccines, although they are biological medicinal products, are also out of scope.

National extensions will have to make decisions about the scope of their medicinal product terminology as they may require representation of products that are beyond the international scope, and therefore may need to author, at a minimum, Clinical Drug concepts within their extension (for example to describe national pharmacopoeial formulations). In addition, national extensions will need to set a scope for the range of medicinal products to be included; factors to consider comprise:

• Licensed medicinal products (i.e. those with a valid authorisation within the jurisdiction of the extension)
  • This may or may not include those licensed for sale or supply without an order (prescription) from a healthcare professional, depending on scope; these products are often known as "over the counter" medicines
• Unlicensed medicinal products
  • Previously licensed medicinal products (i.e. those that have, at some point in the last but which no longer hold a valid authorisation within the jurisdiction of the extension); some may continue to be available via import (see next point below)
  • Medicinal products holding a valid authorisation in a different jurisdiction but which are (regularly) used within the jurisdiction of the extension by practitioners on their own clinical responsibility
  • Medicinal products that are compounded according to recognised formulae; these are usually produced by authorised compounding units
  • Investigational medicinal products (if and when good sources of this information become available through IDMP)

In all of the above, a reliable source of information for all the definitional attributes will be required; this may be challenging for unlicensed medicines and even for some "over the counter" medicines.

One thing that may be helpful in setting the boundary for national scope is to include those products that can be 'legally supplied'; in most healthcare cultures, compounded products, unlicensed and investigational products can be legally supplied to patients provided the terms and conditions of the jurisdiction are fulfilled.  In addition, scope setting will need to bear in mind how to respond to the changes in the availability of products over time and the use case(s) for historic information for products that are no longer available in the supply chain.

This specification does not propose a model for the types of additional information that may be a useful part of a national medicinal product terminology, such as product availability or pricing. That is a matter for each jurisdiction. The principles for the status of the terminology concepts themselves should be as in the core (i.e. active - intended for terminology use; inactive - not intended for terminology use).

Audience

This document is written primarily for those responsible for the development and maintenance of a (national) Medicinal Product terminology within a member nation or other organisation that is managed as a module within a SNOMED CT extension.
It will also be of value to those who have a (national) Medicinal Product terminology that is not managed as a module within a SNOMED CT extension, but who wish to provide a mapping from concepts in their Medicinal Product terminology to concepts in SNOMED CT International Release Medicinal Product hierarchy in order to harness the benefits of the rich international clinical terminology.