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Continuous presentation: bounded by container; liquid dose forms

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Examples: parenteral solutions, unit dose nebuliser solutions

Example: A pack of 10 ampoules each containing 20mL of metoclopramide hydrochloride for solution for injection

Manufactured dose form

Solution for injection

Manufactured dose form

Solution for nebulisation

Continuous presentation: bounded by container; liquid/semi-solid dose forms; concentration strength

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Examples: bulk parenteral solutions, insulins, patches

The unit of presentation usually either uses the same word (even though it is a different concept) as the (package item) container, or the (package item) container is a more granular concept and the unit of presentation uses a less granular term. However, although presentation strength is expressed as "per one unit of presentation", the clinically relevant strength is the concentration strength, as almost all are used in individually calculated and variable amounts. Note that the unit of presentation is likely to be useful in description of the medicinal product concept at some level; insulin presented in a multi-dose vial will be used/administered differently from insulin presented in a cartridge for use within a "pen device".

Example: A pack of 5 cartridges each containing 1.5mL soluble human insulin 100 units/mL solution for injection

Manufactured dose form

Solution for injection

Manufactured dose form

Solution for injection

Manufactured dose form

Transdermal patch

Clinical drug

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

The Clinical Drug "containing precisely" (CD-precise) concept is an abstract representation of the precise active ingredient, basis of strength substance (BoSS), strength, and manufactured dose form of a drug product. It implies that the drug product must contain only the precise active ingredient(s) specified in the FSN.

Clinical Drug with Discrete Dose Form
Clinical Drug with Continuous Dose Form

All Clinical Drugs that contain multiple active ingredient substances will have parent MP and MPF concepts that have the same set of active ingredient substances.

The limitation of the Clinical Drug class to the closed world view by the description of its precise active ingredient substances only precludes description of excipient substances, such as flavours, preservatives, sweeteners, etc., as ingredients in a Clinical Drug. These substances can have significance for allergies, etc., but can only be reliably described for individual authorised manufactured products, and as such, are not within the scope of the international edition.

Similarly, by limiting the Clinical Drug class in the international edition to expression of strength either as concentration strength or as presentation strength, medicinal product concepts that could usefully have both concentration and presentation strength (for example, some liquid products such as liquid parenteral products or liquids for inhalation via a nebuliser) will have only concentration strength in the international edition.

Use cases supported by the clinical drug concept include:

As the abstract representation of products that are authorised, although without any sense of the excipient substances, the clinical drug concept is the source from which all other representation of medicinal product concepts flows; it acts as a clinically relevant grouper concept for medicinal products, and as such can support:
- international cross-border care delivery
- International and national interoperability of patient medication information, such as within patient summaries

This class forms part of the medicinal product content provided in the international edition, although for liquid products, only concentration strength representation is provided.

Clinical Drug concepts in the international release are defined by their precise active ingredient substance(s) and their basis of strength substance, as described above. A concept that grouped clinical drugs by their strength and basis of strength substance only (i.e., disregarding the precise active ingredient substance) may be appropriate in some contexts in national extensions (e.g. 'amlodipine 10mg conventional release oral tablet' as a concept with three child concepts 'amlodipine (as amlodipine besiliate) 10mg conventional release oral tablet' and 'amlodipine (as amlodipine mesiliate) 10mg conventional release oral tablet' 'amlodipine (as amlodipine maleate) 10mg conventional release oral tablet'. A Clinical Drug grouping concept of this nature would be a "Basis of Strength Substance Clinical Drug" concept as opposed to a "Clinical Drug containing Precisely" concept.

Although a Clinical Drug might look directly compatible with the IDMP concept of "Manufactured Item", in IDMP, a Manufactured Item is an "actual manufactured item (the tablet, liquid, cream contained within the package) as it is delivered from the manufacturer but before any transformation, if applicable, for administration to or use by the patient"; it is therefore a representation of a real entity, rather than an abstract entity. They are therefore not directly compatible classes of entities. A Manufactured Item is described by substances in a variety of roles, including excipient substances, not just its active substance(s) and their strengths. A Manufactured Item can be related to an appropriate Clinical Drug on the basis of its active ingredient substance(s) and relevant strength so that the Clinical Drug being an abstracted representation of the Manufactured Item, but they are not equivalent. The Manufactured Item concept in IDMP is equivalent to the Real Clinical Drug concept of the SNOMED national extension model.

On the basis that the IDMP concept of a Pharmaceutical Product could be defined by substance(s) playing only an active ingredient role, then the Clinical Drug concept is more directly compatible with the IDMP Pharmaceutical Product concept however if it is intended that the IDMP Pharmaceutical Product does include excipient substances, then there is no compatibility. Even then, the IDMP Pharmaceutical Product concept is clear that the dose form attribute is populated by the administrable dose form rather than the manufactured dose form, whereas, for everything other than products presented as reconstituted oral liquids, the Clinical Drug uses the manufactured dose form. Although for probably the majority of medicinal products the manufactured dose form is also the administrable dose form, for the minority for which this is not the case (for example, parenteral products presented as powders or granules that must be dissolved or dispersed prior to administration to the patient) this difference is significant. It is therefore not possible to state any direct class level equivalence between a Clinical Drug and an IDMP Pharmaceutical Product.

There is some compatibility between an IDMP PhP4 concept and a Clinical Drug. However, it is not yet clear as to how the "active substance - strength" description will be described in IDMP implementation. The SNOMED Clinical Drug is explicit in stating the basis of strength substance in its relevant granularity as required for patient care; IDMP is currently less clear as to how that will be done and what effect that will have on the description of a Pharmaceutical Product. In addition, IDMP allows for "active substance - strength" to be described by using either (and possibly even both) a Substance and Specified Substance. The distinction between Substance and Specified Substance in IDMP is thus: a substance is "any matter of defined composition that has discrete existence, whose origin may be biological, mineral or chemical" whereas a Specified Substance is one that is "defined by groups of elements that describes multi-substance materials or specifies further information on substances relevant to the description of Medicinal Products". Specified substances are substances like simeticone, which are mixture substances, or substances that are defined by pharmacopoeial specification (like water for injection) or substance where a particular manufacturing process is specified (as for biosimilar products). For SNOMED CT, all such substances, with the possible exception of 'water for injection') could be present in the Substance hierarchy and are therefore candidate concepts to be used in the ingredient role attributes of concepts in the Medicinal Product hierarchy; as such the IDMP distinction between Substance and Specified Substance has no material effect.

The guidance below applies to both discrete and continuous dose forms.

Align FSN and PT naming and case sensitivity with the concepts selected as attribute values.

For multiple-ingredient drug products, the BoSS must be in alphabetical order and separated by the word “and”.

The following units of measure should not be abbreviated in any descriptions; always spell out:

microequivalent
microliter
microgram
microliter (with GB spelling microlitre)

Synonyms matching the FSN are not required.

For solids and semi-solids, a concentration strength will be mass/mass (weight/weight) – usually mg/g.

Solid = pill, tablet, suppository, tape, patch, lozenge, implant, gum, capsule, etc.
Semi-solid = cement, cream, gel, ointment, paste, poultice

For liquids, a concentration strength will be mass/volume (weight/volume) – usually mg/mL.

Liquid = solution, suspension, tincture, spirit, emulsion, foam, lotion, oil, lacquer, etc.

Requests for new concepts that conflict with the above require a clear justification for the variance.

International Unit as a description is arbitrary, and to be understood, each product requires reference to a particular bioefficacy specification for that entity. Therefore, international unit is neither a meaningful nor comparable description at Clinical Drug level. International unit will be represented as unit in Clinical Drug descriptions. Abbreviations will not be used.

For example,
- 1237145006 |Product containing precisely octocog alfa 1000 unit/1 vial powder for conventional release solution for injection (clinical drug)|
- Preferred term: Octocog alfa 1000 unit powder for solution for injection vial

The |Has presentation strength numerator unit| will still continue to have a value of |International unit (qualifier value)| even though unit is stated in the FSN and PT.

Concepts with product strength that is "not equal to" are modeled as primitive, with attributes added as described in the corresponding subpages, except that strength numerator attributes will not be added. The appropriate Medicinal Product Form-only (MPF-only) concept will infer as a parent.

Expression of product strength in metric units is preferred.

To avoid semantically equivalent concepts, product strength for metric units are normalized as follows:

Use milligram if value is <1000; if > 1000, convert to gram.
Use microgram if value is <1000; if > 1000, convert to milligram.
Use nanogram if value is <1000; if > 1000, convert to microgram.

Similarly, if a unit is less than one, convert to a smaller unit. gram → milligram → microgram → nanogram → picogram

For example,
- If the value is less than one gram, convert value to milligrams.

To avoid semantically equivalent concepts, product strength for units are normalized as follows:

Use million unit if value is > 1000000 unit

The following units are not allowed unless specifically noted as an exception:

408165007 |Mega u (qualifier value)|

Repeating decimals are rounded to three decimal places (with 5 and above rounded up and 4 and below rounded down).

The Precise Active Ingredient (PAI) cannot be modeled as a substance hydrate or solvate unless the BoSS is expressed as a substance hydrate or solvate.

Concepts containing pancreatic enzymes are modeled based on the discrete enzymes; because of variability between real clinical drugs, synonyms representing a total amount in a particular product will not be included in the International Release.

Clinical drugs containing precisely x are modeled with a count based on the substance(s) to support a closed world view (i.e., a count of 1 will not infer a count of 2). The closed world view does not apply to dose forms. A very rare case can arise where, for example, a clinical drug that is for an x ear and eye drop is a subtype of both the clinical drug x eye drop and the clinical drug x ear drop. This makes real world sense where all descendants of x clinical drug eye drop are for use in the eye, and a small subgroup of them may also be acceptable for use in the ear.

For example,
- 1220547004 |Product containing precisely gentamicin (as gentamicin sulfate) 3 milligram/1 milliliter conventional release eye drops (clinical drug)| correctly infers a subtype of 1142217003 |Product containing precisely gentamicin (as gentamicin sulfate) 3 milligram/1 milliliter conventional release ear and eye drops (clinical drug)|.

Clinical Drug with Discrete Dose Form

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Overview

Clinical drug concepts representing discrete dose form (e.g., tablets, capsules, pessaries, suppositories, sachets, patches, ampules or vials containing solid dose forms such as powders or granules, and metered dose delivery products such as inhalers and spray) are modeled using presentation strength attributes; concentration strength attributes are not allowed for these concepts in the International Release. Clinical drugs with a discrete dose form using presentation strength represents a medicinal product based on description of 1) its precise active ingredient substances only and explicitly, 2) the stated basis of strength substance(s) with strength, expressed as presentation strength with unit of presentation and 3) with its manufactured dose form.

For example,

Product containing precisely abacavir 300 milligram/1 each conventional release oral tablet (clinical drug)
Product containing precisely abacavir 600 milligram and lamivudine 300 milligram/1 each conventional release oral tablet (clinical drug)
Product containing precisely afatinib (as afatinib dimaleate) 30 milligram/1 each conventional release oral tablet (clinical drug)
Product containing precisely aztreonam 500 milligram/1 vial powder for conventional release solution for injection (clinical drug)
Product containing precisely flucloxacillin (as flucloxacillin sodium) 250 milligram/1 vial powder for conventional release solution for injection (clinical drug)
Product containing precisely budesonide 200 microgram/1 actuation conventional release powder for inhalation (clinical drug)
Product containing precisely nicotine 7 milligram/24 hour prolonged-release transdermal patch (clinical drug)

When a product has a metered delivery, the strength is "per actuation" not as a concentration.

For example
1263426000 |Product containing precisely xylometazoline hydrochloride 140 microgram/1 actuation conventional release nasal spray (clinical drug)|

Use one of the following patterns for the FSN and PT.

Where Precise active ingredient = BoSS and Unit of presentation = discrete solid dose form (e.g. capsule, lozenge, pessary, suppository, tablet):

Product containing precisely <BoSS FSN> <Presentation strength numerator value FSN> <Presentation strength numerator unit FSN>/<Presentation strength denominator value FSN> each <Manufactured dose form FSN> (clinical drug)

For example,
- Product containing precisely abacavir 300 milligram/1 each conventional release oral tablet (clinical drug)
- Product containing precisely abacavir 600 milligram and lamivudine 300 milligram/1 each conventional release oral tablet (clinical drug)

Where Precise active ingredient is not = BoSS and Unit of presentation = discrete solid dose form (e.g. capsule, lozenge, pessary, suppository, tablet):

Product containing precisely <BoSS FSN> (as <Precise active ingredient FSN>) <Presentation strength numerator value FSN> <Presentation strength numerator unit FSN>/<Presentation strength denominator value FSN> each <Manufactured dose form FSN> (clinical drug)

For example,
- Product containing precisely doxazosin (as doxazosin mesilate) 4 milligram/1 each conventional release oral tablet (clinical drug)
- Product containing precisely disopyramide (as disopyramide phosphate) 150 milligram/1 each prolonged-release oral tablet (clinical drug)

Where Precise active ingredient = BoSS and Unit of presentation = other discrete dose form (e.g. actuation, vial, sachet)

Product containing precisely <BoSS FSN> <Presentation strength numerator value FSN> <Presentation strength numerator unit FSN>/Presentation strength denominator value FSN> <Presentation strength denominator unit FSN> Manufactured dose form FSN> (clinical drug)

For example,
- Product containing precisely aztreonam 500 milligram/1 vial powder for conventional release solution for injection (clinical drug)
- Product containing precisely budesonide 200 microgram/1 actuation conventional release powder for inhalation (clinical drug)

Where Precise active ingredient is not = BoSS and Unit of presentation = other discrete dose form (e.g. actuation, vial, sachet)

For example,
- Product containing precisely flucloxacillin (as flucloxacillin sodium) 250 milligram/1 vial powder for conventional release solution for injection (clinical drug)
- Product containing precisely buserelin (as buserelin acetate) 100 microgram/1 actuation conventional release nasal spray (clinical drug)

Where BoSS = Precise active ingredient:

<BoSS PT> <Presentation strength numerator value PT> <Presentation strength numerator unit PT> <Manufactured dose form PT> <Has unit of presentation PT>

For example,

Abacavir 300 mg oral tablet
Abacavir 600 mg and lamivudine 300 mg oral tablet
Atropine sulfate 600 microgram oral tablet
Codeine sulfate 15 mg oral tablet

Where BoSS is not = Precise active ingredient:

<BoSS PT> (as <Precise active ingredient PT>) <Presentation strength numerator value PT> <Presentation strength numerator unit PT> <Manufactured dose form PT> <Has unit of presentation PT>

For example,

US PT: Doxazosin (as doxazosin mesylate) 4 mg oral tablet
GB PT: Doxazosin (as doxazosin mesylate) 4 mg oral tablet
US/GB PT: Disopyramide (as disopyramide phosphate) 150 mg prolonged-release oral tablet

Synonyms matching the FSN are not required.

Clinical Drug with Continuous Dose Form

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Overview

Clinical drugs representing a continuous dose form are modeled using concentration strength attributes. Clinical drugs with a continuous dose form using concentration strength represents a medicinal product based on description of 1) its precise active ingredient substances only and explicitly, 2) the stated basis of strength substance(s) with strength, expressed as concentration strength and 3) with its manufactured dose form (with the exception of reconstituted oral liquid preparations, where the administrable dose form is be used as it is the most clinically relevant).

This is used for product types such as cutaneous semi-solids (without metered actuation), solutions, suspensions, creams, ointments, bulk powders and granules, topical liquids (without metered actuation) including drops, oral liquids, nebuliser liquids and liquid parenteral products.

For example,

Product containing precisely zidovudine 10 milligram/1 milliliter conventional release oral solution (clinical drug)
Product containing precisely amikacin (as amikacin sulfate) 250 milligram/1 milliliter conventional release solution for injection (clinical drug)
Product containing precisely clotrimazole 10 milligram/1 gram conventional release cutaneous cream (clinical drug)
Product containing precisely mupirocin (as mupirocin calcium) 20 milligram/1 gram conventional release nasal ointment (clinical drug)

Where Precise active ingredient = BoSS:

Product containing precisely <BoSS FSN> <Concentration strength numerator value FSN> <Concentration strength numerator unit FSN>/<Concentration strength denominator value FSN> <Concentration strength denominator unit FSN> <Manufactured dose form FSN> (clinical drug)

For example,

Product containing precisely amitriptyline hydrochloride 5 milligram/1 milliliter conventional release oral solution (clinical drug)
Product containing precisely buprenorphine 70 microgram/1 hour prolonged-release transdermal patch (clinical drug)
Product containing precisely clotrimazole 10 milligram/1 gram conventional release cutaneous cream (clinical drug)

Where Precise active ingredient is not = BoSS:

Product containing precisely <BoSS FSN> (as <Precise active ingredient FSN>) <Concentration strength numerator value FSN> <Concentration strength numerator unit FSN>/<Concentration strength denominator value FSN> <Concentration strength denominator unit FSN> <Manufactured dose form FSN> (clinical drug)

For example,

Product containing precisely amikacin (as amikacin sulfate) 250 milligram/1 milliliter conventional release solution for injection (clinical drug)
Product containing precisely mupirocin (as mupirocin calcium) 20 milligram/1 gram conventional release nasal ointment (clinical drug)

Where Single ingredient with BoSS = Precise active ingredient:

<BoSS PT> <Concentration strength numerator value PT> <Concentration strength numerator unit PT>/<Concentration strength denominator value PT> <Concentration strength denominator unit PT> <Manufactured dose form PT>

For example,

Amitriptyline hydrochloride 5 mg/mL oral solution
Buprenorphine 70 microgram/hour prolonged-release transdermal patch
Clotrimazole 10 mg/g cutaneous cream

Where Single ingredient with BoSS is not = Precise active ingredient:

<BoSS PT> (as <Precise active ingredient PT>) <Concentration strength numerator value PT> <Concentration strength numerator unit PT>/<Concentration strength denominator value PT> <Concentration strength denominator unit PT> <Manufactured dose form PT>

For example,

Amikacin (as amikacin sulfate) 250 mg/mL solution for injection
Mupirocin (as mupirocin calcium) 20 mg/g nasal ointment

Synonyms converting metric units to percent or parts per millions may be included for medical gas concepts (e.g. Helium 79% and oxygen 21% gas for inhalation, Helium 790,000 ppm and oxygen 210,000 ppm gas for inhalation).

Specific Clinical drug modeling

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Anhydrous

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

When a clinical drug has a BoSS specified in a Summary of Product Characteristics as an anhydrous substance, the PAI is represented as the unmodified substance, i.e., the substance with an unspecified level of hydration.

Examples:
1153520006 |Product containing precisely carbidopa anhydrous (as carbidopa) 25 milligram and levodopa 250 milligram/1 each conventional release oral tablet (clinical drug)|

The SPC states each tablet "contains 27.0 mg carbidopa (equivalent to 25 mg of anhydrous carbidopa) and 250 mg levodopa." The BoSS is anhydrous carbidopa, so the PAI is Carbidopa.

1331919008 |Product containing precisely carbidopa anhydrous (as carbidopa) 12.5 milligram and entacapone 200 milligram and levodopa 50 milligram/1 each conventional release oral tablet (clinical drug)|

states, "Each film-coated tablet contains 50 mg of levodopa, 12.5 mg of carbidopa anhydrous (as 13.5 mg carbidopa monohydrate) and 200 mg of entacapone." The Boss is anhydrous carbidopa, so the PAI is Carbidopa.

Prolonged-release transdermal patch

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Prolonged-release transdermal patch clinical drug concepts modeled previously using concentration strength normalized to per 1 hour will use presentation strength based on the labeled total amount delivered over time (e.g., /16, /24 [usual manufacturer-documented period], /72 hours), in alignment with product SPCs and international editorial policy.

Opioid patches (e.g., fentanyl, buprenorphine) are an exception and must retain the /1 hour expression, consistent with manufacturer documentation and regulatory standards. This reflects patient safety requirements for these strong, controlled substances. These concepts must also be modeled using presentation strength.

Presentation strength is to be used for all prolonged-release transdermal patch concepts.
The |Has unit of presentation (attribute)| with a value of |Patch (unit of presentation)| is added to all prolonged-release transdermal patch concepts.

Units will reflect the duration, strength, and units as specified in the SPC.

Sodium valproate and Valproic acid

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

The Count of active ingredient (attribute) relationship has been added to certain single-ingredient valproic acid or sodium valproate clinical drug concepts to prevent incorrect subsumption under multiple-ingredient concepts (such as those containing both sodium valproate and valproic acid). This modeling ensures correct classification, particularly when substances share a base moiety but differ at the modification level.

For example
765633006 |Product containing precisely sodium valproate 200 milligram/1 each prolonged-release oral tablet (clinical drug)| includes a |Count of active ingredient (attribute)| to prevent it from being inferred as a parent of 1204385002 |Product containing precisely sodium valproate 200 milligram and valproic acid 87 milligram/1 each prolonged-release oral tablet (clinical drug)|.

In addition, when any concept in a sibling set requires the additional |Count of active ingredient| attribute to classify correctly, this attribute should also be added to all sibling concepts for consistency.

Vaccine Products in the Medicinal Product Hierarchy

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

The following sections apply to the vaccine product concepts in the |Medicinal product (product)| hierarchy in the International Release. In the International Release, vaccine products are those concepts with |Plays role (attribute) = |Active immunity stimulant role (role)|.

Products that provide passive immunity should be modeled using the general Medicinal product guidance.

See also the relevant section in Substances on Antibodies and antigens.

Vaccine Product Top Level Groupers Vaccine Product containing Concepts Vaccine Product containing only Concepts

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Basic Dose Form

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

The basic dose form represents a general type of pharmaceutical formulation (e.g. tablet, capsule, cream, ointment, solution, emulsion) used for medicinal products. To support fully defining concepts in the 736542009 |Pharmaceutical dose form (dose form)| hierarchy, a hierarchy representing basic dose form is required.

Medicinal Product Form Precisely (MPF precisely)

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Medicinal Product Form Precisely (MPF precisely)

This concept class, which is not shown in any of the overall diagrams in the introductory page, would be a representation of a medicinal product based on description of only and exclusively the precise active ingredient(s) it contains and on the (generalised) intended site of use for the product. For example, "Product containing precisely amoxicillin trihydrate in oral dosage form" represents products that must contain only amoxicillin trihydrate (not amoxicillin sodium or amoxicillin base) as the precise ingredient substance, with no other active ingredients in manufactured dose forms such as oral suspension, oral capsule (any type), oral tablet (any type). This class is not part of the international edition, but may be of use in national extensions. It would be modelled in the same way as the MPF only, but would use the precise active ingredient attribute and the two additional ingredient count attributes if and when required, using the same rules as for MP precisely.

Provide Feedback

Clinical drug

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Clinical Drug with Discrete Dose Form
Clinical Drug with Continuous Dose Form

All Clinical Drugs that contain multiple active ingredient substances will have parent MP and MPF concepts that have the same set of active ingredient substances.

Use cases supported by the clinical drug concept include:

As the abstract representation of products that are authorised, although without any sense of the excipient substances, the clinical drug concept is the source from which all other representation of medicinal product concepts flows; it acts as a clinically relevant grouper concept for medicinal products, and as such can support:
- international cross-border care delivery
- International and national interoperability of patient medication information, such as within patient summaries

This class forms part of the medicinal product content provided in the international edition, although for liquid products, only concentration strength representation is provided.

The guidance below applies to both discrete and continuous dose forms.

Align FSN and PT naming and case sensitivity with the concepts selected as attribute values.

For multiple-ingredient drug products, the BoSS must be in alphabetical order and separated by the word “and”.

The following units of measure should not be abbreviated in any descriptions; always spell out:

microequivalent
microliter
microgram
microliter (with GB spelling microlitre)

Synonyms matching the FSN are not required.

For solids and semi-solids, a concentration strength will be mass/mass (weight/weight) – usually mg/g.

Solid = pill, tablet, suppository, tape, patch, lozenge, implant, gum, capsule, etc.
Semi-solid = cement, cream, gel, ointment, paste, poultice

For liquids, a concentration strength will be mass/volume (weight/volume) – usually mg/mL.

Liquid = solution, suspension, tincture, spirit, emulsion, foam, lotion, oil, lacquer, etc.

Requests for new concepts that conflict with the above require a clear justification for the variance.

For example,
- 1237145006 |Product containing precisely octocog alfa 1000 unit/1 vial powder for conventional release solution for injection (clinical drug)|
- Preferred term: Octocog alfa 1000 unit powder for solution for injection vial

The |Has presentation strength numerator unit| will still continue to have a value of |International unit (qualifier value)| even though unit is stated in the FSN and PT.

Expression of product strength in metric units is preferred.

To avoid semantically equivalent concepts, product strength for metric units are normalized as follows:

Use milligram if value is <1000; if > 1000, convert to gram.
Use microgram if value is <1000; if > 1000, convert to milligram.
Use nanogram if value is <1000; if > 1000, convert to microgram.

Similarly, if a unit is less than one, convert to a smaller unit. gram → milligram → microgram → nanogram → picogram

For example,
- If the value is less than one gram, convert value to milligrams.

To avoid semantically equivalent concepts, product strength for units are normalized as follows:

Use million unit if value is > 1000000 unit

The following units are not allowed unless specifically noted as an exception:

408165007 |Mega u (qualifier value)|

Repeating decimals are rounded to three decimal places (with 5 and above rounded up and 4 and below rounded down).

The Precise Active Ingredient (PAI) cannot be modeled as a substance hydrate or solvate unless the BoSS is expressed as a substance hydrate or solvate.

For example,
- 1220547004 |Product containing precisely gentamicin (as gentamicin sulfate) 3 milligram/1 milliliter conventional release eye drops (clinical drug)| correctly infers a subtype of 1142217003 |Product containing precisely gentamicin (as gentamicin sulfate) 3 milligram/1 milliliter conventional release ear and eye drops (clinical drug)|.

Pharmaceutical and Biologic Product

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Definition

A top-level hierarchy to clearly distinguish drug products (products) from their chemical constituents (substances)

Purpose of the SNOMED CT Medicinal Product hierarchy

The SNOMED CT Medicinal Product hierarchy provides concepts to describe medicinal products at various levels of abstraction with international applicability and support for interoperability in patient care and health data analysis. It provides a foundation from which member nations can extend with additional concepts suitable for their own healthcare culture and practice, or to which existing terminology can be mapped if required.

This document describes the model for the concepts in the medicinal product hierarchy in the international edition of SNOMED CT; when populated, this model will provide:

concepts in the international edition to meet the core use cases
a foundation for national medicinal product terminologies
- For member nations with an existing terminology, the model underpinning the concepts will facilitate both direct use or mapping

This document also provides a description of how aspects of the SNOMED medicinal product hierarchy correspond with the suite of standards in ISO (Internal Organization for Standardization), collectively known as the "Identification of Medicinal Products standards" (IDMP). These IDMP standards provide a conceptual model for the unique identification of a medicinal product globally and standard terminology concepts to support this (for example, to describe substances and dose forms). The domain of use for the IDMP standards is primarily the regulatory domain, but since regulatory information is the source and underpinning for the description of medication and medicinal product concepts in a clinical/patient care medicinal product terminology, both internationally and nationally, it is important that the SNOMED CT medicinal product model and supporting concepts are in harmony with those standards. Compatibility with the IDMP model for identification of medicinal products will facilitate information flow between the two domains of use (for example, to support pharmacovigilance). However, there is no sense that this harmony entails “full and exact compliance”; there would be little value in exact duplication. The SNOMED CT medicinal product hierarchy therefore provides classes of concepts that are additional to those present in the IDMP model to support the specific SNOMED CT and patient care/health data analysis use cases.

The scope of specification for the concept model for representation of medicinal products in the international edition of SNOMED CT is limited to pharmaceutical and biological products only; products that represent blood products, foods/nutritional supplements, additives, and complementary medicines (including homeopathic products) are currently out of scope. The representation of autologous medicinal products (those created from tissue and administered back to an individual) is also out of scope. Concepts for vaccines also follow the pattern of this model, although only to two of the three "levels" (MP and MPF). Further detail can be found in the .

The international medicinal product model and concepts in the international edition are described in their more abstract form; real or actual products (including branded products and those marketed without a brand name) as authorised by medicines regulatory agencies within jurisdictions are out of scope. Describing the packages in which medicinal products are placed into the supply chain are also out of scope; both of these areas are covered in the national model specification.

This document is written for everyone with an interest in the development, maintenance, and use of medicinal product concepts within SNOMED CT, including those in member nations who are or wish to use medicinal product concepts from the international edition, either directly (in an extension where appropriate) or by mapping, in any national/local medicinal product terminology. It is relevant to those responsible for clinical or research systems using medicinal product concepts in both active medication processes (prescribing, dispensing, and administering medicines) or in recording of medication information, and also particularly to those responsible for systems providing decision support for medication safety.

The main use cases for the medicinal product hierarchy in the international edition of SNOMED CT are as follows:

To provide a consistent and usable set of international medications concepts for member nations to use as a foundation for national medicinal product terminology
1. For those member nations with an existing terminology, the improved model underpinning the concepts will facilitate both direct use or mapping
2. For those member nations without an existing terminology, the concepts provide a consistent starting set of concepts and a model to develop from, reducing resource (especially set up costs) and risk in development

SNOMED CT as an ontology is constructed on the principle of an open world view (the existential restriction) with each concept having a distinct fully specified name. The implication of the open world view for the medicinal product hierarchy is that a concept represents the set of (real world) medicinal products that contains "(at least) some substance X as an active ingredient", but may contain other unspecified active ingredient substances. This 'open world' view is useful for analysis and in some types of decision support. However, the regulation of medicinal products for sale/supply is based on the 'closed world' view (the universal restriction), where all active ingredient substances must be explicitly described. This is also the premise for description of medicinal products in the medication process (prescribing, dispensing and administration). Therefore, the Medicinal Product hierarchy differs from other concept hierarchies within SNOMED CT in that some classes of concepts within it are modeled using this 'closed world' view, which states that a concept represents a medicinal product that contains "only substance X as an active ingredient"; no other active ingredient substances are present within it. To implement that "closed world view" with the existing tools and systems of SNOMED CT, the "ingredient count" proxy has been developed. Some description of this is given below, with further detailed information being available in the machine-readable concept model. For further details on the open and closed world views, please refer to the relevant SNOMED documentation and training materials.

IDMP, being a suite of standards developed in and for the regulatory domain, uses a "closed world" view. The active ingredient substance(s) present in a product must be listed in full, with no exceptions, so IDMP exists in the "closed world" view and therefore would be compatible with the "universal restriction" only; the existential restriction is not compatible with the concepts in the IDMP suite of standards, which is particularly important to note for the abstract concepts within IDMP in ISO 11616 (PhPIDs, especially L1, L3 and L4).

In maintaining a medicinal product terminology, concepts are authored to describe those things that exist and can be used in clinical care and/or clinical research. This means that it is the more granular concepts that are usually recognised first, then the less concrete concepts are abstracted from these. In many medicinal product terminologies, this results in there being lowest level child concepts for every parent concept within the model classes. Due to the historic nature of some of the content in the SNOMED CT international edition medicinal product hierarchy, there will be higher level parent concepts (i.e., MP and MPF concepts) that do not have clinical drug concepts associated with them. These MP and MPF concepts may have had clinical drug type concepts associated with them in the past, but the veracity and provenance of the detailed information to support these CD concepts could not be confirmed, so they have been inactivated, whereas the more abstract MP and MPF concepts remain in the international release to support historic data use cases such as analysis and medication profiles.

There is nothing in the specification that deals with availability of medicinal products for use; neither the presence of a concept nor an absence of a concept gives any sense of its availability in the supply chain globally. Indeed, even when a medicinal product ceases to be available anywhere in the global supply chain, its representation will remain as a valid concept in SNOMED CT for use in patient medication history and patient medication profiles. New medicinal products, both from newly authorised therapeutic substances and in new formulations of existing therapeutic substances, are constantly appearing globally. The principles and process for the ongoing maintenance of and addition of new content to the medicinal product hierarchy are being developed as part of the Editorial Guidelines.

The definition of the 763158003 |Medicinal product (product)| concept as providing the scope of the hierarchy is in agreement with the scope of the concept of a medicinal product in IDMP. This is a positive position generally and particularly for any future mapping exercise that might be undertaken, since there should be few concepts that cannot be mapped at some level of granularity. However, in IDMP, and specifically in ISO 11615, the Medicinal Product class represents an authorised medicinal product that consists of one or more Manufactured Items as authorised and available; in this sense it is much more concrete concept than the SNOMED parent concept. This difference is not of great significance other than to understand that the same term ("medicinal product") has a different and more specific meaning in IDMP than in the SNOMED CT medicinal product model. Also, the IDMP ISO 11615 model explicitly describes and includes "combination medicinal products" (also known as 'kit' products, 'component' products, 'multi-component packaged products', etc.) where the package placed into the supply chain contains more than one type of component element (clinical drug) within it; since these are correctly packaged products, and packaged products are out of scope of the medicinal product hierarchy for the international edition of SNOMED CT, these combination products are not represented in this SNOMED CT model.

The |Pharmaceutical / biologic product (product)| hierarchy is comprised of multiple smaller hierarchies. It contains the following semantic tags:

(medicinal product)
(clinical drug)
(medicinal product form)
(product)

National Drug Extension Model

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Model Overview

The diagram below shows the concept classes for the extension model with the related concept classes from the international medicinal product model. No role or grouper classes (i.e., parents of the international Medicinal Product (MP) class) are shown in the diagram. It is expected that all grouping classes (based on substance structure, disposition and therapeutic role) will be inherited from the international release. For all of the classes in the national drug extension model, the closed world view applies. Products are defined using only the active ingredient substances as authorised by the regulatory agency in the particular jurisdiction of use. Packs are defined using only the clinical drug concepts that they are composed of (contain) (see also Supporting Attributes).

In the diagram, the MP classes are shown in shades of blue, the MPF classes in shades of yellow, the CD classes in shades of green and the PCD classes in shades of orange; the concepts represent the real world medicinal products available within a nation and described within that extension are shown in the brighter shades.

Classes of National Drug Extension Model

The five concept classes of the international release are shown on the left hand side in their three levels or groups (MP, MPF, and CD) with their two representations - the containing and the only - of the open and closed world views respectively. The sixth and optional class of MP Precisely is also shown, as that class may be used in a national extension model, if required.

The classes of the national extension model are, with the exception of the MP Precisely and the PCD, shown on the right hand side. Two of the classes of the national extension model mirror classes in the international model; their concepts represent the real world medicinal products available within a nation that are types of the concepts in the international release:

The optional Real Medicinal Product (RMP) mirrors the Medicinal Product Only class and represents products marketed by a single organisation (supplier) under a single name (which may be a trade or brand name) and which contain the same set of active ingredient substances.
The Real Clinical Drug (RCD) mirrors the Clinical Drug class and represents a product marketed by a single organisation (supplier) under a single name (which may be a trade or brand name) which contains the same set of active ingredient substances in the same strength and which is formulated within a single dose form; this class, like its partner in the international edition content, is at the core of the specification.

Then there are three classes in the national extension model that represent classes that are more specific than the classes of the international model in that they represent either a more specific abstraction of a medicinal product (the MP Precisely) or medicinal products as they are presented in the supply chain in packages for clinical/patient use in a particular country. Any subpackaging used inside a single package (for example, blister strips) and the aggregate packaging used in wholesaling and delivery, such as shrink-wraps and pallets, are excluded. The three additional package classes are:

The optional Medicinal Product Precisely (MP Precisely) which is an abstract representation of a medicinal product based on description of only and exclusively the precise active ingredients it contains.
The optional Real Packaged Clinical Drug (RPCD) which is a representation of a packaged product marketed by a single organisation (manufacturer or supplier) under a single name (which may be a trade or brand name) which contains one or more Real Clinical Drugs within it, in set amounts.
The optional Packaged Clinical Drug (PCD) which is an abstract representation of the Real Packaged Clinical Drug in that it has no manufacturer or supplier information and therefore represents a package containing one or more Clinical Drugs within it, in set amounts.

All concept classes in the national extension model use the closed world view and therefore include the ingredient count attributes, because when describing the real products that are authorised for supply in a country, what is stated about them must be true, and only what is stated can be true.

No requirement has been identified to suggest that the MPF class from the international core requires a mirrored class in the national extension model.

Definitions and detailed descriptions of the extension classes are given in the sections below this model introduction.

Extensions may wish to populate and use all of the classes described in the model, or they may wish to use only a subset; it is envisaged that the clinical drug class from the international core will be foundational, as will the real clinical drug in a national extension, but all others may be considered optional for implementation.

For example,

Some nations may not require packaged clinical drug or real packaged clinical drug concepts if all products are licensed and used in healthcare at the real clinical drug level.
Conversely, if a nation licenses all its products at the real packaged clinical drug level and uses those concepts in their healthcare culture, the real clinical drug class should be populated, as it acts as a grouper concept for all the packages associated with it. This grouper concept is important particularly if extensions require additional product characteristic information, such as for excipients of concern.

Similarly, some nations may require the MP Precisely concept for some classes of medicines where the precise ingredient substance can affect the clinical characteristics such as potency (e.g., glucocorticosteroids) if these concepts need to be available to support dose based prescribing (i.e., prescribing that specifies a medicine concept, plus a route of administration, a dose quantity and a dose frequency, but does not specify a dose form or a strength, so therefore not a clinical drug with its precise ingredient substance). MP Precisely concepts can be authored in a national extension.

Extensions may wish to author additional clinical drug concepts using a presentation strength description for liquid products for which the international release has only a concentration strength representation.

All authored concepts should classify correctly despite the absence of some intermediary classes, provided that they have been modeled according to the SNOMED International standards, that is using the proximal primitive parent and the relevant attributes for the concept class.

The model uses the standard generalisation/specialisation relationship between the mirrored "real" classes of the national extension and their abstract classes in the international core. It also uses a partitive relationship, shown in the diagram as the specialised composition relationship (the 'live together, die together' relationship), between the Clinical Drug and Packaged Clinical Drug classes, indicating that the Packaged Drug classes are "composed of" concepts that are themselves Clinical Drugs. This is reflected in the 774160008 | Contains clinical drug (attribute)| that is part of the logical definition of a Packaged Clinical Drug. The composition relationship is particularly appropriate for those packaged medicinal products that contain more than one clinical drug (often referred to as kit products). The combination of the usual SNOMED CT generalisation relationship and partitive relationship is manageable within SNOMED CT tooling and will be applicable for description of other types of product concepts within the overall scope of SNOMED CT, such as medical devices, which are often composed of more than one type of entity (e.g., drug eluting stents). The use of the composition relationship between Clinical Drugs and Packaged Clinical Drugs means that if implementations wish to display Packaged Clinical Drugs with a direct relationship to the Clinical Drugs that they contain (as in "under" them in a hierarchical display), and they wish to transfer information such as the therapeutic role from the Clinical Drug to the Packaged Clinical Drug that they are related to, this composition relationship and the 774160008 | Contains clinical drug (attribute)| must be used to facilitate that.

The relationships in the diagram are shown only in terms of their semantics; no cardinality is given. National extensions may populate those classes for which they have use cases; for example, if a nation has no requirement for the Real Medicinal Product class, it does not have to be populated.

The international core content of SNOMED CT will provide all the attribute relationships needed to define medicinal product concepts in a national extension. These will be suitably defined according to SNOMED CT Machine-Readable Concept Model (MRCM) principles and available for use in the tooling. The concepts to provide the values for the product name and supplier cannot be present in the International edition, as these do not have international applicability or even international uniqueness (especially for product name). This specification therefore cannot provide ranges for these attributes; the supertype concepts are available ( 774167006 | Product name (product name)| and 774164004 | Supplier (supplier)| ) to support extension authoring.

For various reasons, not all the individual Medicinal Product and Clinical Drug concepts that a nation requires may be present in the International edition; some additional content may require authoring in the nation's own extension. All the substance, dose form, unit of presentation, and package type concepts to value the attributes should be available in the international content to satisfy the interoperability use cases for the medicinal product hierarchy. Strengths can be described accurately using the appropriate integer or decimal, following editorial rules.

All concepts in the classes of the national extension model should be modelled using the proximal primitive parent modeling pattern and be fully defined wherever possible, using the attribute relationships and values from the international content for the substance, dose form and unit of presentation concepts and values from the national extension for product names and manufacturer/supplier organisations, but it is accepted that some primitive concepts may have to be authored.

Ingredient Substance Attributes

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

The following sections discuss the attribute concepts used to represent the ingredient substances of concepts in the medicinal product hierarchy.

Ingredient Substances

Figure: Ingredient role attributes

The diagram above shows the relationship of the various attribute roles that a substance can play in the definition of MP, MPF and CD description of medicinal products. Any concept from the Substance hierarchy may play one or more of these roles within a product. In all of the descriptions below, when the phrase "a set of substances" is used, the set may have only one member.

Has ingredient

A medicinal product concept has a set of substances that are combined to manufacture the medicinal product that can be described using the "has ingredient" attribute. However, each substance(s) in the "has ingredient" set will have more specific ingredient role that should be described using that more specific concept. Therefore, this is a grouping concept that is not used for definition of medicinal product concepts in the medicinal product hierarchy; it is a parent concept and it provides scope for further child concepts to be added to support future use cases, such as the description of inactive/excipient ingredient substances in products in a national extension. The physical presence or otherwise of an ingredient substance in the finished product may not explicitly be necessary for it to be part of the product's substance description; for example substances that play a role in the manufacturing process, such as solvents etc. are deemed "ingredients" for the product; their presence may or may not remain in the manufactured item. As such, basis of strength substance could be considered as a child concept of the Has ingredient concept, although it is not modeled in that way currently.

A medicinal product concept has a set of active ingredient substance(s) responsible for providing the therapeutic effect of the medicinal product and which are described using the clinically relevant part or whole of the substance that is intended to have a therapeutic action on or within the body. In the majority of cases, this description excludes modifiers such as esters, salts or other non-covalent derivatives (such as a complex, chelate etc.), but may include them in the minority of cases when clinically significant (e.g. liposomal substances). This is therefore usually an abstract representation of the active ingredient substance(s) and is used in more abstract representations of medicinal products, such as MP (containing).

Note that "clinical significance" can be described as "something that has a practical, demonstrable effect on the treatment and condition of the patient". For example: different modifiers of a particular active moiety have clinical significance if they affect the potency of the therapeutic action of the moiety (and therefore have an affect on the dose quantities to be used). See Kazdin, E The Meanings and Measurement of Clinical Significance Journal of Consulting and Clinical Consulting 67 (3): 332–9. This is the attribute role that is used in the definition of the MP concept (containing and only) and the MPF concept. Examples of substances playing the role of active ingredient in a medicinal product:

azithromycin where the precise active ingredient may be azithromycin hemiethanolate, azithromycin isopropanolate
haloperidol where the precise active ingredient may be haloperidol hydrochloride, haloperidol decanoate, haloperidol lactate
esomeprazole where the precise active ingredient may be esomeprazole magnesium, esomeprazole sodium

A medicinal product concept has a set of precise active ingredient substance(s), those substance(s) that provides the therapeutic effect of the medicinal product and which are described using the fullest and most specific description of the substance as it is used in the product(s) that the concept represents (as they are presented by the manufacturer in the manufactured dose form, before any dilution or transformation). The precise active ingredient substance may include various modifiers, such as salts, esters and/or polymers (e.g. pegylation); not all substances, even when used as the precise active ingredient substance, have a modification (see axitnitib). This is the attribute role that is used in the definition of the MP (precisely) concept, and in the definition of the CD (precisely). Examples:

haloperidol decanoate
oxybutynin chloride
dexamethasone sodium phosphate
sorafenib tosylate

The precise active ingredient attribute will use the Substance hierarchy as a flat list (without role chaining), so that a Clinical Drug containing a modified substance is not subsumed under a clinical drug containing the unmodified substance, thereby unintentionally adding more recursion to the clinical drug class (for example: so that a morphine (base) precise clinical drug does not subsume a clinical drug containing precisely morphine sulphate). This highlights the difference between the semantic of "contains precisely" which explicitly and exclusively describes the full modified substance in the medicinal product concept and "contains only" which inclusively describes the therapeutically active moiety which may be manifest in one or more substance modifications of itself.

Examples:

"contains dexamethasone only" means that a product will contain only dexamethasone as its active ingredient; but that dexamethasone may be present as dexamethasone base, as dexamethasone phosphate, dexamethasone sodium phosphate, as dexamethasone acetate, as dexamethasone palmitate etc.
"contains dexamethasone phosphate only" means that a product can contain either dexamethasone phosphate or dexamethasone sodium phosphate (which is a modification of dexamethasone phosphate) as its active ingredient; but it will not contain dexamethasone acetate or dexamethasone palmitate etc.
"contains dexamethasone phosphate precisely" means that a product will contain exclusively dexamethasone phosphate; dexamethasone sodium phosphate will not be present

See also the subsection below "Using the ingredient roles" which provides a diagram further describing the use of role chaining with the active ingredient role and that there is no role chaining for the precise active ingredient role.

A medicinal product clinical drug concept has one or more substances that have the role of being the substance against which the strength quantity(s) of the product(s) are measured. There will be a basis of strength substance stated for each active ingredient substance present in a multi-ingredient clinical drug product.

Examples:

azithromycin - in an oral suspension containing azithromycin hemiethanolate, where the strength is 100 mg per 5 mL of azithromycin
haloperidol in a solution for injection containing haloperidol decanoate, where the strength is 250 mg per 5 mL of haloperidol
esomeprazole - in a prolonged release tablet containing esomeprazole magnesium, where the strength is 20 mg per tablet of esomeprazole

Almost always, the basis of strength substance is either the active ingredient substance or the precise active ingredient substance; very occasionally products are licensed using a "reference" basis of strength substance (e.g. a product containing diclofenac diethylammonium as its precise active ingredient substance having its strength expressed in terms of diclofenac sodium).

The Medicinal Product and Medicinal Product Form use the active ingredient attribute, which will have a role chain attached to it, so that it can use the Substance hierarchy as a hierarchy through the "is modification" relationship. This allows the classifier to make the appropriate relationships between MPs, MPFs and CDs based on their active ingredient substances. The role chain is a characteristic that is not inherited, so the precise active ingredient attribute does not inherit this characteristic. The Clinical Drug uses the precise active ingredient attribute/relationship which will use the Substance hierarchy as a flat list without role chaining, so that a clinical drug containing a modified substance is not subsumed under a clinical drug containing the unmodified substance, thereby unintentionally adding more recursion to the clinical drug class (for example: so that a morphine (base) precise clinical drug does not subsume a clinical drug containing precisely morphine sulphate).

Ingredient role is a specific attribute in ISO 11615 in IDMP, but no vocabulary/value set was specified in the conceptual standard for the ingredient roles. Examples that have been given include "active", "inactive" and "adjuvant". This supports the regulatory listing of all the substances present in a product, with their basic role (therapeutic or otherwise).

The explicit use of ingredient roles in the medicinal product model is compatible with the IDMP conceptual model; however, the relationship of ingredient role to substance strength is still being elucidated in IDMP. Note that the concept of "basis of strength substance", in the very few cases where it is not actually a substance present in the product, is managed by the use of the Reference Substance class in IDMP. See also .

Introduction

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Rationale for the National Drug Extension Model

The international content of SNOMED CT is, by definition, globally applicable. For example, most clinicians will agree on what constitutes a diagnosis of atrial fibrillation and how this concept should be logically defined. Therefore, wherever in the world a patient suffers from atrial fibrillation, there is a common understanding of what that is, and the SNOMED CT concept for atrial fibrillation can represent and reflect that.

But medicinal products are different. 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 (whenever possible) using their international non-proprietary names (INNs) 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 (represented as a concrete value) and units (represented as a SNOMED CT concept)
- Pharmacopoeial / internationally defined dose forms
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")

International SNOMED CT releases contain concepts of the first type, i.e., 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 to enable each country to express their medicinal products with their names, their definitions, and if required, additional defining attributes that fit with their regulation and their healthcare culture and practice. This national drug extension model is provided to support the authoring of drug concepts of this second type, and to enable the sharing of tools (e.g., drug authoring tools), rules (e.g., international decision support rules), and drug extension content (e.g., to support the interoperability of a patient's medication information, for cross-border dispensing with contraindication checking).

National drug extensions have to support a variety of use cases; these can include any or all of:

Prescribing medicines - such that medicinal products are described in sufficient detail that the next action in the process (either dispensing or administration) can identify the correct product to dispense/administer
Dispensing
- Reimbursement information

The drug extension concept model can be used to represent the real or actual medicinal products (sometimes referred to as branded products) available for use in a particular country/territory. This model is compatible with the international core model for Medicinal Products. This compatibility means that, when classified using the appropriate tooling, the extension concepts will be correctly placed alongside other concepts in the international Medicinal Product hierarchy.

Detailed rules and processes required to populate a national terminology are not described here. General principles are given, and terming suggestions are provided. However, national extensions must be mindful of their own terming requirements when authoring synonyms to support direct implementation. In situations where additional concepts for core classes of the international model are required in the national extension (e.g., MP, MPF, and CD), the naming guidelines for the international release should be followed (particularly for the FSN).

General principles for authoring SNOMED CT extension content can be found in the Extensions Practical Guide at .

The scope of this concept model (as defined) is limited to medicinal products (pharmaceutical and biological). Blood products, foods, additives, and complementary medicines (including homeopathic products) are out of scope. Vaccines are also out of scope (even though they are biological medicinal products).

National extensions will need to make decisions about the scope of their own medicinal product terminology and may require the representation of products that are beyond the international scope. In these cases, it may be necessary to author Clinical Drug concepts (and their associated MP and MPFs) within the extension (e.g., 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 include:

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. These products are often known as "over the counter" medicines.
Unlicensed medicinal products

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

It can be helpful when considering the boundary for inclusion of products in the national extension (if the national prescribing use case is in scope), 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. The scope must also 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. 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). The implications of this, in terms of use cases for active supply of medicines, must also be considered.

This specification does not propose a model for the types of additional knowledge that may be a useful part of a national medicinal product catalogue, such as product availability or pricing. That is a matter for each jurisdiction.

This document is written primarily for those responsible for the development and maintenance of a Medicinal Product terminology (national, regional or organisational) that is managed within a SNOMED CT extension. However, it will also be of value to those who have an existing Medicinal Product terminology (national, regional or organisational) which may or may not be managed in a SNOMED CT extension, who wish to develop a mapping from concepts in their own Medicinal Product terminology to a standardized SNOMED CT representation to harness the interoperability benefits of using a common concept model defined in a clinical reference terminology.

Clinical Drug (CD) with Concentration and Presentation Strengths

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Clinical drug concepts in the international edition are authored either using presentation strength (for discrete dose forms) or using concentration strength (for liquid dose forms and patches, etc.) as appropriate for different types of product (see Clinical Drug with Continuous Dose Form, Clinical Drug with Discrete Dose Form, and Appendix A: Product Patterns). Concentration strength in SNOMED CT is where the description of the strength of a clinical drug has been normalized such that the denominator value is "one" and the denominator unit is a unit of mass (e.g., grams) or volume (e.g., milliliters). Presentation strength is a description of the strength of the clinical drug as it is present in its unit of presentation (vial, ampoule, sachet).

By limiting the the Clinical Drug class in the international edition to expression of strength either as concentration strength or as presentation strength, medicinal product concepts that could usefully have both concentration and presentation strength (for example, some liquid products such as liquid parenteral products or liquids for inhalation via a nebulizer) will have only concentration strength in the international edition. National extensions may author clinical drug concepts using the presentation strength(s) and unit(s) of presentation available in their jurisdiction if use case(s) require this. These concepts will be child concepts of the concentration clinical drug in the international edition. The diagrams below illustrate this:

In national extensions, the concentration strength clinical drug may be sufficient, or there may be a requirement to represent some, usually liquid dose form product clinical drugs, using both concentration and presentation strength either for the abstract clinical drug, or for the real clinical drug, or for both. This is shown in the diagram below:

Even within a single jurisdiction, authorizations are not always consistent in dealing with presentation and concentration strength. Some regulatory agencies have or are moving to licensing all parenteral liquid products using presentation strength (with the exception of some products such as insulins and large volume parenteral fluid replacement products and bulk use vials, etc.); other agencies have been or are using this pattern for some products (e.g., pre-filled syringes) and may change for others as IDMP takes effect. Some national terminologies are working to normalise the patterns of strength representation particularly for safety considerations; others are dealing with the mixed economy that exists "as is". This specification provides support for the different patterns for both clinical drugs and real clinical drugs whilst maintaining the requirement that concepts will classify correctly within the system.

This modeling pattern is advised for use with usually liquid products that are placed inside a unit of presentation such as an ampoule, vial, cartridge or pre-filled syringe, which itself is then put inside a package, usually but not always with other identical units, for placement into the supply chain. For these products, the presentation strength is itself often clinically relevant, and therefore, although the fully specified name pattern (as currently described) uses the concentration strength, a synonym (which could be the preferred term for a national extension) could use the presentation strength description; for example: "enoxaparin sodium 120 milligram/0.8 millilitre conventional release solution for injection in pre-filled syringe".

As the unit of presentation is the "countable entity" of the clinical drug, this modeling pattern is not advised for continuous semi-solids (creams, ointments, etc.) or continuous liquids (oral solutions, suspensions) where there is no "countable entity". The unit of presentation should not be confused with the package for continuous semi-solids and liquids that is placed into the supply chain (tubes, bottles, etc.). The package should be described using the (R)PCD structure which describes the package size but not currently the package type. For example: chloramphenicol 5 milligram/1 milliliter conventional release eye drops are supplied in a 10mL bottle; the clinically relevant information is the "10mL" volume, which is the package size.

This is the pattern for a national extension to author a presentation strength representation of a clinical drug that is described using concentration strength in the international edition. This can be used for:

liquid parenteral products presented in units of presentation, such as ampoules, vials, pre-filled syringes, cartridges, or bags/bottles
liquid oral products presented in a sachet or other unit dose unit of presentation
liquid pulmonary products presented in a unit dose presentation unit of presentation

In addition to the usual attributes for a concentration strength clinical drug, the unit of presentation size and unit of presentation unit attributes are used. The concept will then classify correctly as a child of the existing concentration strength clinical drug. This does mean that the exact presentation strength must be authored manually as an additional description and that the exact presentation strength is not provided in the logical definition (other than via calculation), but this pattern has been found to be the most efficient method for authoring such concepts, especially when there are multiple active ingredient substances. The alternative was to author both concentration strength and presentation strength in two role groups, which, whilst it does also give the correct classification, is very labour intensive.

The following attributes apply to Clinical Drug (CD) concepts in a national extension, which require both concentration and presentation strength.

Semantic tag

(clinical drug)

Also note that the unit of presentation, the unit of presentation size quantity, and the unit of presentation size unit are not role grouped together, as there should only ever be 0..1 of each present for any one clinical drug concept.

For clinical drugs that have two or more active ingredient substances that are modifications of the same base substance, and where MP precisely concepts are required in the national extension, and for single ingredient product concepts where the active substance is an ingredient in these multiple modification multi-ingredient products, the following extra ingredient count attribute will be required in order to support correct relationships generated by the MRCM:

Attribute 1142141006 | Count of base and modification pair |

| INT (integer) 1..1 Range Cardinality | | ------------------------------------------------------------------------------------ | ------------------------------------ |

For concepts that have two or more active ingredient substances that are modifications of the same base active ingredient substance (i.e., parent ingredient substance) and where one is a further modification of the other (for example, a multi-ingredient product containing both dexamethasone phosphate and dexamethasone sodium phosphate, where the dexamethasone phosphate is a modification of dexamethasone (base) and dexamethasone sodium phosphate is a further modification of the dexamethasone phosphate) and where MP precisely concepts are required in the national extension, and for single ingredient product concepts where the active substance is an ingredient in these multiple modification multi-ingredient products, the following extra ingredient count attribute will be required in order to support correct relationships generated by the MRCM:

Some examples of clinical drug concepts, with concentration strength and presentation strength in a national drug extension, are shown below.

Stated template view:

Example: single active ingredient substance clinical drug with concentration and presentation strength for a national extension

Real Clinical Drug (RCD)

This Editorial Guide is used for Education Purposes Only. It is used in the Authoring Courses and Certifications. It is based on the January 2026 Editorial Guide.

Definition

The representation of a medicinal product marketed by a single organization (supplier) in a single jurisdiction under a single name (which may be a trade or brand name or a generic/non-proprietary name) and which contains the same set precise active ingredient substances and strengths in a single manufactured dose form. It is a subtype of and real world equivalent to the Clinical Drug (CD) class in the international edition of SNOMED CT.

Use Cases

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

Supporting medication process activities: prescribing, dispensing, administration and medication statements
- In prescribing and in medication statements, especially in situations where the patient should always use a particular Manufactured Product, for reasons of bioavailability (such as a lithium product) or use of administration system (such as an insulin pen)
- In dispensing and administration, to identify exactly which product was provided/administered
Reimbursement: national or local systems may set pricing or eligibility against particular manufactured products, regardless of how they are supplied (i.e., with no reference to pack size)
Allergy checking of specific excipients (if described)
Pharmacovigilance

The real clinical drug represents the product as most (but not all) regulatory authorities grant the marketing authorization, with the individual packaged products that are marketed into the supply chain in any jurisdiction included within that authorization. A small number of regulatory authorities license each package of a medicinal product separately which is represented by the real packaged clinical drug (see below). Real medicinal products must be represented using the closed world view; they contain only the content as stated in the logical definition. Since this class represents real products as authorized in a jurisdiction, description of additional non-defining information, such as excipient substances (flavors, preservatives, sweeteners, etc.) or details about the product name parts or product authorization information and product availability information can be attached to Real Clinical Drug concepts, should a national extension wish to do this. For further details, see the section on Optional Additional Information below.

The real clinical drug is the marketed (therefore "real") instantiation in any one country of the abstract clinical drug in the international edition, and as such, real clinical drugs classify as child concepts of the clinical drug as well as a child concepts of the real medicinal product, if one has been authored. This concept class is, like the clinical drug in the international edition, at the core of the way medicinal products are described, and as such, should always be used in a national extension.

Existing national terminology equivalents:

Actual Medicinal Product in NHS dm+d and Belgian SAM
Trade Product Unit of Use in in AMT/NZULM
Semantic Branded Drug (SBD) in RxNorm

The real clinical drug class inherits from the clinical drug class in the international edition, and the product name and supplier from the real medicinal product class.

In the following table, two relationship groups (marked with *) are described: one for presentation strength, and one for concentration strength. The appropriate relationship group type(s) should be selected based on the real product being described. A liquid product being described using a presentation strength in a national extension should follow the pattern used for "" in this specification.

Semantic tag

(real clinical drug)

(One per precise active ingredient)

For real clinical drugs that have two or more active ingredient substances that are modifications of the same base substance and where MP precisely concepts are required in the national extension, and for single ingredient product concepts where the active substance is an ingredient in these multiple modification multi-ingredient products, the following extra ingredient count attribute is required in order to support correct relationships generated by the MRCM:

Attribute:

1142141006 | Count of base and modification pair |

| INT (integer) 1..1 Range Cardinality | | --------------------------------------------------------------------------- | ------------------------------------ |

Attribute:

1142140007 | Count of active ingredient |

| INT (integer) 1..1 Range Cardinality | | ------------------------------------------------------------------ | ------------------------------------ |

Note : The cardinalities given in the above table are for concepts in the RCD class. These cardinalities may be stricter than those in the MRCM, which typically apply across a broader range of concepts.

Some examples of real clinical drug concepts are shown below.

Example: single active ingredient substance branded product (Canesten) (concentration strength): stated view followed by the inferred view

In this example, a concentration and presentation strength clinical drug has been authored in the national extension, and therefore, the real clinical drug classifies under this concept.

In this example, a concentration and presentation strength clinical drug has been NOT authored in the national extension, and therefore, the real clinical drug classifies under the concentration strength concept in the international edition.

National extensions that function as national medicinal product dictionaries may require information that extends beyond the characteristics of the product as described here in this specification for real clinical drugs. Product characteristics can be included within the SNOMED CT structure using attributes and values, whereas knowledge about the product should be managed alongside the SNOMED CT structure (e.g., in a reference set), and relationships between identification systems should be managed in cross maps.

Product characteristics may include describing excipient substances to support allergy or intolerance checking. Excipient substance roles may include flavors, colors, preservatives, and stabilizers/fillers.
Knowledge about the product may include usage information, such as availability within the supply chain, licensing/authorization category and/or legal status of supply and prescribability information including reimbursement categories
Other identification systems for a real clinical drug may include licensing/authorization number or Global Trade Identification Number (GTIN)

In jurisdictions where repackaging and/or parallel importing are authorised, a national extension may wish to consider having a relationship between the repackaged or parallel imported real clinical drug and the real clinical drug supplied by the original manufacturer, if that is present within the jurisdiction.

For most authorised medicinal products, this class is roughly equivalent to the core Medicinal Product class, with its MPID identification in ISO 11615 of IDMP. However, the Medicinal Product class in IDMP explicitly includes combination (kit) products, whereas this model describes combination products as packaged products only. Implementation considerations may require combination products to be available to users alongside clinical drug and real clinical drug concepts; mechanisms, such as the use of reference sets, can support this requirement.

Continuous presentation: bounded by container; liquid dose forms

Example: A pack of 10 ampoules each containing 20mL of metoclopramide hydrochloride for solution for injection

Continuous presentation: bounded by container; liquid/semi-solid dose forms; concentration strength

Example: A pack of 5 cartridges each containing 1.5mL soluble human insulin 100 units/mL solution for injection

Clinical drug

Clinical Drug with Discrete Dose Form

Overview

Clinical Drug with Continuous Dose Form

Overview

Specific Clinical drug modeling

Subpages

Anhydrous

Prolonged-release transdermal patch

Sodium valproate and Valproic acid

Vaccine Products in the Medicinal Product Hierarchy

Basic Dose Form

Medicinal Product Form Precisely (MPF precisely)

Medicinal Product Form Precisely (MPF precisely)

Specific Clinical drug modeling

Subpages

Prolonged-release transdermal patch

Anhydrous

Clinical Drug with Discrete Dose Form

Overview

Modeling

Naming

FSN

Preferred Term

Synonym

Exemplars

Stated Template View

Example Concepts

Clinical Drug with Continuous Dose Form

Overview

Modeling

Naming

FSN

Preferred Term

Synonym

Exemplars

Stated template view

Example Concepts

Sodium valproate and Valproic acid

Clinical drug

Use cases supported by the Clinical Drug concept

Availability of CD concepts in the international edition

Clinical Drug Grouping Concepts not present in this model or in the international edition

IDMP Compatibility

Descriptions

Concentration strength units

International Unit

Product strength not equal to

Product strength numerator values

Precise active ingredient

Inference based on dose form

Medicinal Product Form Precisely (MPF precisely)

Medicinal Product Form Precisely (MPF precisely)

Continuous presentation: bounded by container; liquid dose forms

Example: A pack of 10 ampoules each containing 20mL of metoclopramide hydrochloride for solution for injection

Example: A pack of 20 UDVs each containing 2mL of ipratropium bromide for solution for nebulisation

Vaccine Products in the Medicinal Product Hierarchy

Continuous presentation: bounded by container; liquid/semi-solid dose forms; concentration strength

Example: A pack of 5 cartridges each containing 1.5mL soluble human insulin 100 units/mL solution for injection

Example: Box of 10 bags of Sodium chloride 0.9% solution for infusion 500mL

Example: A pack of 30 sachets each containing a transdermal patch delivering 4.6mg per 24 hours of rivastigmine

Basic Dose Form

Overview

Modeling

Naming Guidelines for Grouper Concept

FSN

Preferred Term

Synonym

Text Definitions

Exemplars for Grouper Concept

Naming Guidelines for Basic Dose Form Concept

FSN

Preferred Term

Synonym

Text Definitions

Exemplars for Basic Dose Form Concept