Updating the SNOMED CT UK Drug Extension model

NHS England is making a number of changes to align the SNOMED CT UK Drug Extension modelling to reflect the SNOMED International model for national drug extensions, where it is deemed to fit UK requirements. This work is being done to enable the NHS to use functionality available in the RF2 format, that was not previously available in RF1, which restricted how certain aspects of the UK Drug Extension could be implemented. 

This work will also enable the NHS to use the power of our authoring tools, enhance our quality assurance processes and work towards international standardisation.

We will be carrying out this work over a number of phases and will update this webpage with more detailed information about the changes as it becomes available.

Phase 1

Aligning dm+d VMP class medicinal products to the SNOMED International drug model. 

Phase 2 

Removal of Grouper Concepts

Aligning dm+d VMP class medicinal products to the SNOMED International drug model

The scope of this work is the modelling of VMP classes, their attributes, and their descriptions. 

Attribute alignment 

To align the current dm+d VMP model to the SNOMED International drug model, a number of attributes need to be reviewed (either removed or added to the model).

These are:

• Has specific active ingredient
• Has NHS BoSS (Basis of Strength Substance)
• Count of base of active ingredient
• Count of active ingredient
• Has manufactured dose form
• Has Unit of presentation
• Strength values and units

A number of attributes will remain unchanged as they do not require any modification.

These are:

• Freeness indicator
• Prescribing status
• Non-availability indicator
• Has controlled drug category
• Combination product indicator
• Dose form indicator
• Has ontology form and route
• Has route of administration
• Unit of administration (for insulin and drop dose forms) 
• Has dispensed dose form

Description alignment

VMP class descriptions to be reviewed are:

• Fully Specified Names* 
• Synonyms

*The proposal by SNOMED International to increase the maximum length of Fully Specified Name (FSN) and Synonym descriptions, from 255 to 4096 characters, will impact FSNs created in the SNOMED CT UK Drug Extension.

Removal of Grouper concepts

‘Grouper concepts’ are concepts in the SNOMED CT UK Drug Extension that ‘group together’ concepts from dm+d. NHS England is proposing grouper concepts for medicinal product concepts are no longer used and replaced with Refsets.

The current grouper concepts are:

• 10363701000001104 |Virtual therapeutic moiety (product)|
• 10363801000001108 |Virtual medicinal product (product)|
• 10363901000001102 |Actual medicinal product (product)|
• 8653601000001108 |Virtual medicinal product pack (product)|
• 12222901000001103 |Actual radiopharmaceutical product pack (product)|

Example: The concept 10363701000001104 |Virtual therapeutic moiety (product)| is the parent for every dm+d VTM.

Dictionary of medicines and devices (dm+d) - NHS Business services Authority
Contains dm+d Data Model, dm+d Editorial Policy and dm+d Technical Specification of data files

SNOMED CT UK Drug Extension Editorial Policy and Model
SNOMED CT Medicinal Product Model Specification

Quarter 1 2025: User survey regarding impacts from this work

NHS England sought views from SNOMED CT UK Drug Extension users to understand the impacts of this work and how much lead in time users require to manage the changes. The user survey ran from 25 March to 22 April 2025.

Quarter 2 2025: Outcomes of user survey 

NHS England has analysed the survey responses. A summary of the findings are:

1. There is concern from terminology users as to the impact of this work on the NHS dictionary of medicines and devices (dm+d). It is therefore important to clarify this work will not impact dm+d in anyway. This information has also been prominently displayed at the top of this webpage to clearly communicate this.
2. Users want specific details of the changes, with examples, guidance, timelines and test files. This feedback will inform our website content and supporting resources. We will continue to update this webpage to provide this information to assist users as it becomes available.

If users would like to discuss this work further, please contact: [email protected].