> 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/snomed-international-drug-model.md).

# SNOMED International Drug Model

### Overview

The SNOMED CT International Drug Model provides a standardized framework for representing medicinal products in a manner that is consistent across countries and healthcare systems. The model is part of the Pharmaceutical / Biologic Product hierarchy and defines a set of concept classes that represent medicinal products at different levels of abstraction.

The international model focuses on representing the clinical characteristics of medicinal products, including:

* active ingredient(s)
* dose form
* strength

These characteristics allow medicines to be represented in a way that is independent of local brand names, packaging, or regulatory authorizations.

## Core Concept Classes in the International Drug Model

The international drug model defines several concept classes that represent medicinal products at different levels of abstraction. These concept classes allow systems to represent medications with the level of detail required for different clinical and administrative workflows.

### Medicinal Product (MP)

A Medicinal Product represents a medicinal product defined only by its active ingredient(s). It does not specify dose form or strength.

This level is commonly used for:

* ingredient-based decision support rules
* drug interaction checking
* pharmacovigilance analysis
* high-level reporting and analytics

| Concept Class          | Description                                  | Example                        |
| ---------------------- | -------------------------------------------- | ------------------------------ |
| Medicinal Product (MP) | Product defined by active ingredient(s) only | Product containing amoxicillin |

### Medicinal Product Form (MPF)

A Medicinal Product Form represents a medicinal product defined by active ingredient(s) and dose form, but without specifying strength.

This level allows grouping of products that share the same ingredient and pharmaceutical form.

Typical uses include:

* prescribing templates
* clinical decision support rules specific to dose form
* reporting and aggregation

| Concept Class                | Description                                    | Example                                                  |
| ---------------------------- | ---------------------------------------------- | -------------------------------------------------------- |
| Medicinal Product Form (MPF) | Product defined by ingredient(s) and dose form | Product containing amoxicillin in oral capsule dose form |

### Clinical Drug (CD)

A Clinical Drug represents a medicinal product defined by:

* active ingredient(s)
* strength
* manufactured dose form

This level provides the detail required for most clinical workflows such as prescribing and medication administration.

<table><thead><tr><th width="191.078125">Concept Class</th><th>Description</th><th>Example</th></tr></thead><tbody><tr><td>Clinical Drug (CD)</td><td>Product defined by ingredient(s), strength, and dose form</td><td>Amoxicillin 500 mg oral capsule</td></tr></tbody></table>

Clinical Drug concepts represent generic clinical specifications of medicines, independent of brand names or manufacturers.

## Relationship Between Concept Classes

The concept classes of the international drug model form a hierarchy that supports aggregation and semantic reasoning.

For example:

```
Medicinal Product
    Product containing amoxicillin
        ↓
Medicinal Product Form
    Product containing amoxicillin in oral capsule dose form
        ↓
Clinical Drug
    Amoxicillin 500 mg oral capsule
```

This hierarchical structure allows:

* aggregation of detailed data for reporting
* decision support rules defined at the ingredient level to apply to all related products
* consistent interpretation of medication data across systems

## Key Attributes Used in the Drug Model

The international drug model uses a set of defining attributes to describe medicinal products. These attributes allow drug concepts to be formally defined and classified within the SNOMED CT hierarchy.

Common attributes include:

<table><thead><tr><th>Attribute</th><th width="325.88671875">Description</th><th>Example</th></tr></thead><tbody><tr><td>Has active ingredient</td><td>Specifies the active substance(s) in the medicinal product</td><td>Amoxicillin</td></tr><tr><td>Has basis of strength substance</td><td>Identifies the substance used to express the strength</td><td>Amoxicillin trihydrate</td></tr><tr><td>Has manufactured dose form</td><td>Specifies the pharmaceutical dose form</td><td>Oral capsule</td></tr><tr><td>Has strength</td><td>Specifies the amount of active substance</td><td>500 mg</td></tr></tbody></table>

These attributes enable consistent modeling and automated classification of medicinal product concepts.

## Relationship to National Drug Extensions

The international drug model provides the clinical foundation for representing medicinal products, but it does not represent jurisdiction-specific details such as:

* brand names
* authorized products
* packaging information
* pack sizes
* locally marketed products

These concepts are represented in National SNOMED CT Drug Extensions, which extend the international model to support local regulatory and clinical requirements.

For example:

| Model Level                                     | Example                                      |
| ----------------------------------------------- | -------------------------------------------- |
| Clinical Drug (International)                   | Amoxicillin 500 mg capsule                   |
| Real Clinical Drug (National Extension)         | Brand X Amoxicillin 500 mg capsule           |
| Real Clinical Drug Package (National Extension) | Brand X Amoxicillin 500 mg capsule box of 24 |

The international model therefore provides the semantic backbone for national drug extensions, ensuring that medicines can be represented consistently across jurisdictions.

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