Packaged Clinical Drug (PCD)

Definition: A representation of a medicinal product as it is supplied in a package for placement into the supply chain, based on description of and quantity of the clinical drug(s) contained within that package. As an abstract class, the Packaged Clinical Drug is placed on the left hand side of the overall model, relating directly to the Clinical Drug class in the international core by means of a composition relationship, but its population is the responsibility of national extensions since the amount of content needed to support this internationally would be overwhelming and unmanageable in maintenance and verification.

This definition supports the description of kit or combination products (medicinal products that are composed of more than one Clinical Drug - such as a package containing fluconazole oral capsules and clotrimazole cream for treatment of vaginal thrush) as Packaged Clinical Drugs, and therefore the pack size information for each Clinical Drug that is a component in the package is grouped together. Further detail on the description of combination products (multi-component or kit products) is given in Section 11 below.

Packs of medicinal products must be represented using the closed world view; they contain only the clinical drug content stated. To correctly describe that and to ensure that pack concepts classify correctly, so that packs that contain more than one (type of) clinical drug (i.e. combination packs) do not classify as children of packs that contain only one type of clinical drug, it is necessary to use a count attribute as a proxy for the closed world view. This mirrors the use of the count attribute for active ingredient in the MP only, MPF only and CD concepts in the main medicinal product hierarchy. By using a "count" attribute in the definition of Clinical Drug and Package concepts, when concreted domains are implemented in the SNOMED CT overall concept model, the count information will be machine processable; similarly if/when a more expressive description logic becomes available to properly represent the closed world view, then all the count attributes can be removed consistently.

The national extension model does not represent intermediate layers of packaging; it represents only the outer package used in the supply chain. Describing "sub-packs" (e.g. tablets within blister sleeves, which are then within a container such as a box) is complex for a description logic based model. In most nations, sub-packs are re primarily used for supply chain management and reimbursement purposes, and possibly rounding of dispense amounts so that sub packs are not split. Many medicinal product terminologies do not represent sub-packs.  ISO 11615, the Medicinal Product part of the IDMP suite of standards, has a full sub-pack mode, but the sub-packs themselves are not identified concepts and so are not available for mapping etc.; however the GS1 implementation of ISO TS 16791 does include identification of sub packs. The basic model described here does not deal with sub-packs; a concept model for sub-packs will not be undertaken until there are requests with confirmed clinical use cases. See also Appendix 2.

Figure 16: Diagram the Packaged Clinical Drug class and its composition relationship to Clinical Drug, with an example

Existing national terminology equivalents:

• • UK's NHS dm+d this is the Virtual Medicinal Product Pack (VMPP) class
  • The AMT/NZULM it is the Medicinal Product Pack
  • In Ireland, this is in effect those packaged products on the Representative Pricing list
  • The generic pack (GPCK) class in RxNorm

Attributes of Packaged Clinical Drug

The following is described for Packaged Clinical Drugs that contain one Clinical Drug only, that is they are NOT combination (multi-component or kit) products. See Section 11 below for Combination Products.

The Packaged Clinical Drug class is related to the Clinical Drug class by a composition relationship relationship, and therefore the attribute "contains clinical drug" is used to make the association between the Packaged Clinical Drug and the Clinical Drugs it contains. 

Representation of packaged medicinal products should use Clinical Drugs that have presentation strength (either only or in addition to concentration strength) whenever possible in order to be able to accurately describe the number of presentation units present in the package. The exception will be for continuous products such as semi-solid dose forms of creams, gels etc. where strength pattern 3a is used (see international Editorial Guidelines). In all cases the pack size and pack size unit should relate to the denominator unit of the strength.

Note 1: It is currently not possible to explicitly specify an expression to describe the range of Clinical Drugs to populate this attribute, since (for example) a range cannot currently recognise a set of concepts with a particular semantic tag - in this case "(clinical drug)". This may be possible in the future; alternatively the range expression might be expressed as: "all products with a dose form, precise ingredient substance and basis of strength substance". For the interim, the range is specified as the descendants of the root medicinal product concept: 763158003 |Medicinal product (product)|.

Note 2: More specific range expressions such as "One of EITHER 732935002 | Unit of presentation (unit of presentation) - descendants only OR 258680008 | Unit of mass (qualifier value) - descendants only OR 258769000 | Unit of volume (qualifier value) - descendants only" are currently not supported, nor are rules based on the strength patterns that (for example) assert "if the clinical drug has a unit of presentation of 'tablet' then the Has_pack_size_unit will be valued as 'tablet"). Therefore, the Has_pack_size_unit should be explicitly valued.

Examples

Stated template view:

Figure 17: Template for Packaged Clinical Drug

Example (stated view):

Figure 18: Example of a packaged clinical drug - stated view

Example (inferred view):

Figure 19: Example of a packaged clinical drug - inferred view

Optional additional information

The following information may be additionally used to describe the Packaged Clinical Drug concept in a national extension. The attribute concepts and values to populate these if this data is to be held in a structured form, may be available in the international release in the future, particularly for those concepts such as package/container types that have international applicability and which can be sourced and maintained reliably.

• Package/container type (e.g. bottle, box, jar, tube) - see 10.6
• Administration device supplied in the package (e.g. medicine spoon, vaginal applicator, applicator brush for cutaneous liquid products)

Use cases supported by Packaged Clinical Drug

The following use cases are supported by the Packaged Clinical Drug concept class:

• Reimbursement: national or local systems may set pricing or eligibility against an abstract representation of real packaged products (e.g. for interchangeability and substitution)
• As a linking class from the international core to the Packaged Product class for any national extension that did not require a Real Clinical Drug class (i.e. if all products are authorised in their packaged form)
• To support description of combination packaged products, if the quantity of each component in the combination packaged product is required

 IDMP Compatibility

There is no representation of a class similar to the Packaged Clinical Drug concept class; the primary use case for this class beyond support for generic representation of combination products is reimbursement, which is out of scope of IDMP. Combination products in their entirety are only represented in IDMP in their authorised form; there is no PhP type representation for them.