# Medication Formula String - Common Components FHIR Implementation Guide v26.0.0

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# Common Components FHIR Implementation Guide

26.0.0 - Trial
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*  [FHIR IGs](https://implementer.digitalhealth.gov.au/fhir-resources) 
*  [Implementer Hub](https://implementer.digitalhealth.gov.au/) 
*  [Agency site](https://www.digitalhealth.gov.au) 

* [**Table of Contents**](toc.md)
* [**FHIR Artefacts**](artifacts.md)
* **Medication Formula String**

## Extension: Medication Formula String 

| | |
| :--- | :--- |
| *Official URL*:http://digitalhealth.gov.au/fhir/cc/StructureDefinition/medication-formula-string | *Version*:26.0.0 |
| Draft as of 2026-07-14 | *Computable Name*:Medication_Formula_String |
| **Copyright/Legal**: This content is licensed under a Creative Commons Attribution 4.0 International License. See [https://creativecommons.org/licenses/by/4.0/](https://creativecommons.org/licenses/by/4.0/) | |

Captures compounded medication formulas from CDA entry relationships to provide formula information in FHIR Medication resources for the PCEHR Prescription and Dispense View.

The purpose of this extension is to carry compounded medication formula text from CDA sources when equivalent structured representation is not available in the base FHIR Medication model.

**Context of Use**

**Usage info**

**Usages:**

* Examples for this Extension: [Medication/medication-cda-extensions-example](Medication-medication-cda-extensions-example.md)

You can also check for [usages in the FHIR IG Statistics](https://packages2.fhir.org/xig/resource/au.gov.digitalhealth.cc|current/StructureDefinition/StructureDefinition-medication-formula-string.json)

### Formal Views of Extension Content

 [Description of Profiles, Differentials, Snapshots, and how the XML and JSON presentations work](http://build.fhir.org/ig/FHIR/ig-guidance/readingIgs.html#structure-definitions). 

 

Other representations of profile: [CSV](StructureDefinition-medication-formula-string.csv), [Excel](StructureDefinition-medication-formula-string.xlsx), [Schematron](StructureDefinition-medication-formula-string.sch) 

#### Constraints

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IG © 2026+ [Australian Digital Health Agency](https://www.digitalhealth.gov.au/). Package au.gov.digitalhealth.cc#26.0.0 based on [FHIR 4.0.1](http://hl7.org/fhir/R4/). Generated 2026-07-14

Links: [Table of Contents](toc.md) | [QA Report](qa.md) | [Version History](https://fhir.digitalhealth.gov.au/dh/history.html) | [Report an issue or propose a change](mailto:help@digitalhealth.gov.au) 

Publisher: [Australian Digital Health Agency](https://www.digitalhealth.gov.au) | ABN: 84 425 496 912, Level 25, 175 Liverpool Street, Sydney, NSW 2000 | Phone: [1300 901 001](tel:1300901001) | Email: [help@digitalhealth.gov.au](mailto:help@digitalhealth.gov.au) | [https://www.digitalhealth.gov.au](https://www.digitalhealth.gov.au) | [Privacy policy](https://www.digitalhealth.gov.au/about-us/policies-privacy-and-reporting/privacy-policy) | [Terms of Use](https://www.digitalhealth.gov.au/about-us/policies-privacy-and-reporting/terms-of-use)

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## Resource Content

```json
{
  "resourceType" : "StructureDefinition",
  "id" : "medication-formula-string",
  "url" : "http://digitalhealth.gov.au/fhir/cc/StructureDefinition/medication-formula-string",
  "version" : "26.0.0",
  "name" : "Medication_Formula_String",
  "title" : "Medication Formula String",
  "status" : "draft",
  "experimental" : false,
  "date" : "2026-07-14T04:17:55+00:00",
  "publisher" : "Australian Digital Health Agency",
  "contact" : [{
    "name" : "Australian Digital Health Agency",
    "telecom" : [{
      "system" : "url",
      "value" : "https://www.digitalhealth.gov.au/"
    },
    {
      "system" : "email",
      "value" : "help@digitalhealth.gov.au"
    }]
  },
  {
    "name" : "Australian Digital Health Agency",
    "telecom" : [{
      "system" : "email",
      "value" : "mailto:help@digitalhealth.gov.au",
      "use" : "work"
    }]
  }],
  "description" : "Captures compounded medication formulas from CDA entry relationships to provide formula information in FHIR Medication resources for the PCEHR Prescription and Dispense View.",
  "jurisdiction" : [{
    "coding" : [{
      "system" : "urn:iso:std:iso:3166",
      "code" : "AU",
      "display" : "Australia"
    }]
  }],
  "purpose" : "The purpose of this extension is to carry compounded medication formula text from CDA sources when equivalent structured representation is not available in the base FHIR Medication model.",
  "copyright" : "This content is licensed under a Creative Commons Attribution 4.0 International License. See [https://creativecommons.org/licenses/by/4.0/](https://creativecommons.org/licenses/by/4.0/)",
  "fhirVersion" : "4.0.1",
  "mapping" : [{
    "identity" : "rim",
    "uri" : "http://hl7.org/v3",
    "name" : "RIM Mapping"
  }],
  "kind" : "complex-type",
  "abstract" : false,
  "context" : [{
    "type" : "element",
    "expression" : "Medication"
  }],
  "type" : "Extension",
  "baseDefinition" : "http://hl7.org/fhir/StructureDefinition/Extension|4.0.1",
  "derivation" : "constraint",
  "differential" : {
    "element" : [{
      "id" : "Extension",
      "path" : "Extension",
      "short" : "Medication Formula String",
      "definition" : "Captures compounded medication formulas from CDA entry relationships to provide formula information in FHIR Medication resources for the PCEHR Prescription and Dispense View."
    },
    {
      "id" : "Extension.extension",
      "path" : "Extension.extension",
      "max" : "0"
    },
    {
      "id" : "Extension.url",
      "path" : "Extension.url",
      "fixedUri" : "http://digitalhealth.gov.au/fhir/cc/StructureDefinition/medication-formula-string"
    },
    {
      "id" : "Extension.value[x]",
      "path" : "Extension.value[x]",
      "short" : "Medication formula text",
      "definition" : "Compounded medication formula captured from CDA entryRelationship/act with code 103.16272 or act with displayName 'Formula'. Contains the textual representation of the medication formula.",
      "type" : [{
        "code" : "string"
      }]
    }]
  }
}

```
