Dose syntax implementation guidance for FHIR STU3

This guidance is under active development by NHS Digital and content may be added or updated on a regular basis.

2. STU3 Limitation - Defining a maximum dose per course

Workaround: Use a free-text `Dosage.additionalInstruction`.

A maximum dose for three scenarios is supported within the STU3 Dosage structure;

  • maxDosePerPeriod - define a maximum dose over a given period of time
  • maxDosePerAdministration - defines a maximum dose per administration
  • maxDosePerLifetime - defines the maximum dose during the lifetime of the patient

Not currently supported is how to define a maximum dose per course.

With the current STU3 Dosage structure, a maximum dose per course would have to be conveyed in free-text using the Dosage.additionalInstruction.

<!--  Defining a maximum dose per course  -->
<!--  Example: Colchicine 500microgram tablets, 500 micrograms, 2 to 4 times a day until symptoms relieved, maximum 6 mg per course, do not repeat course within 3 days  -->
<MedicationRequest xmlns="http://hl7.org/fhir">
    <id value="f27b260e-8bdf-11eb-8dcd-0242ac130003" />
    <contained>
        <Medication>
            <id value="med1" />
            <code>
                <coding>
                    <system value="http://snomed.info/sct" />
                    <code value="330079002" />
                    <display value="Colchicine 500microgram tablets" />
                </coding>
            </code>
        </Medication>
    </contained>
    <status value="active" />
    <intent value="order" />
    <medicationReference>
        <reference value="#med1" />
    </medicationReference>
    <subject>
        <identifier>
            <system value="https://fhir.nhs.uk/Id/nhs-number" />
            <value value="9999999999" />
        </identifier>
    </subject>
    <dosageInstruction>
        <additionalInstruction>
            <text value="Maximum dose per course 6 mg" />
        </additionalInstruction>
        <additionalInstruction>
            <text value="Do not repeat course for 3 days" />
        </additionalInstruction>
        <patientInstruction value="Until symptoms relieved" />
        <timing>
            <repeat>
                <frequency value="2" />
                <frequencyMax value="4" />
                <period value="1" />
                <periodUnit value="d" />
            </repeat>
        </timing>
        <doseQuantity>
            <value value="500" />
            <unit value="microgram" />
            <system value="http://unitsofmeasure.org" />
            <code value="ug" />
        </doseQuantity>
    </dosageInstruction>
</MedicationRequest>

{
    "resourceType": "MedicationRequest",
    "id": "f27b260e-8bdf-11eb-8dcd-0242ac130003",
    "contained":  [
        {
            "resourceType": "Medication",
            "id": "med1",
            "code": {
                "coding":  [
                    {
                        "system": "http://snomed.info/sct",
                        "code": "330079002",
                        "display": "Colchicine 500microgram tablets"
                    }
                ]
            }
        }
    ],
    "status": "active",
    "intent": "order",
    "medicationReference": {
        "reference": "#med1"
    },
    "subject": {
        "identifier": {
            "system": "https://fhir.nhs.uk/Id/nhs-number",
            "value": "9999999999"
        }
    },
    "dosageInstruction":  [
        {
            "additionalInstruction":  [
                {
                    "text": "Maximum dose per course 6 mg"
                },
                {
                    "text": "Do not repeat course for 3 days"
                }
            ],
            "patientInstruction": "Until symptoms relieved",
            "timing": {
                "repeat": {
                    "frequency": 2,
                    "frequencyMax": 4,
                    "period": 1,
                    "periodUnit": "d"
                }
            },
            "doseQuantity": {
                "value": 500,
                "unit": "microgram",
                "system": "http://unitsofmeasure.org",
                "code": "ug"
            }
        }
    ]
}
MedicationRequest.id[0]f27b260e-8bdf-11eb-8dcd-0242ac130003
MedicationRequest.contained[0].id[0]med1
MedicationRequest.contained[0].code[0].coding[0].system[0]http://snomed.info/sct
MedicationRequest.contained[0].code[0].coding[0].code[0]330079002
MedicationRequest.contained[0].code[0].coding[0].display[0]Colchicine 500microgram tablets
MedicationRequest.status[0]active
MedicationRequest.intent[0]order
MedicationRequest.medication[0].reference[0]#med1
MedicationRequest.subject[0].identifier[0].system[0]https://fhir.nhs.uk/Id/nhs-number
MedicationRequest.subject[0].identifier[0].value[0]9999999999
MedicationRequest.dosageInstruction[0].additionalInstruction[0].text[0]Maximum dose per course 6 mg
MedicationRequest.dosageInstruction[0].additionalInstruction[1].text[0]Do not repeat course for 3 days
MedicationRequest.dosageInstruction[0].patientInstruction[0]Until symptoms relieved
MedicationRequest.dosageInstruction[0].timing[0].repeat[0].frequency[0]2
MedicationRequest.dosageInstruction[0].timing[0].repeat[0].frequencyMax[0]4
MedicationRequest.dosageInstruction[0].timing[0].repeat[0].period[0]1
MedicationRequest.dosageInstruction[0].timing[0].repeat[0].periodUnit[0]d
MedicationRequest.dosageInstruction[0].dose[0].value[0]500
MedicationRequest.dosageInstruction[0].dose[0].unit[0]microgram
MedicationRequest.dosageInstruction[0].dose[0].system[0]http://unitsofmeasure.org
MedicationRequest.dosageInstruction[0].dose[0].code[0]ug
MedicationRequest
back to top