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.

1. STU3 Limitation - Combination pack instructions

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

It is common practice to provide a dosage instruction for the combination pack “Migraleve tablets” with instructions for when to take the pink tablets and when to take the yellow tablets. With the current STU3 Dosage structure, these instructions would have to be conveyed in free-text using the Dosage.patientInstructions.

In secondary care the individual components of the pack should be prescribed as separate items.

In primary care the combination pack is prescribed and therefore the medication request must reference the medication resource for the dm+d code of the combination product. The medication request then links to 2 dosing instructions which describe how each tablet should be taken.

<MedicationRequest xmlns="http://hl7.org/fhir">
    <id value="859e5d8a-391a-4b2a-8f29-15e8c75180bb" />
    <contained>
        <Medication>
            <id value="internalMedicationIdentifer123abc" />
            <code>
                <coding>
                    <system value="http://snomed.info/sct" />
                    <code value="3363411000001108" />
                    <display value="Migraleve tablets (McNeil Products Ltd)" />
                </coding>
            </code>
        </Medication>
    </contained>
    <status value="active" />
    <intent value="order" />
    <medicationReference>
        <reference value="#internalMedicationIdentifer123abc" />
        <display value="Migraleve tablets (McNeil Products Ltd)" />
    </medicationReference>
    <subject>
        <identifier>
            <system value="https://fhir.nhs.uk/Id/nhs-number" />
            <value value="9999999999" />
        </identifier>
    </subject>
    <dosageInstruction>
        <sequence value="1" />
        <text value="2 tablets - take once - as required when migraine occurs - Max dose 2 tablets in 24 hours - Pink tablet" />
        <additionalInstruction>
            <text value="Pink tablets" />
        </additionalInstruction>
        <timing>
            <repeat>
                <count value="1" />
            </repeat>
        </timing>
        <asNeededCodeableConcept>
            <coding>
                <system value="http://snomed.info/sct" />
                <code value="37796009" />
                <display value="Migraine" />
            </coding>
        </asNeededCodeableConcept>
        <doseQuantity>
            <value value="2" />
            <unit value="tablet" />
            <system value="http://snomed.info/sct" />
            <code value="428673006" />
        </doseQuantity>
        <maxDosePerPeriod>
            <numerator>
                <value value="2" />
                <unit value="tablet" />
                <system value="http://snomed.info/sct" />
                <code value="428673006" />
            </numerator>
            <denominator>
                <value value="24" />
                <unit value="hour" />
                <system value="http://unitsofmeasure.org" />
                <code value="h" />
            </denominator>
        </maxDosePerPeriod>
    </dosageInstruction>
    <dosageInstruction>
        <sequence value="2" />
        <text value="2 tablets - every 4 hours - as required - max dose 6 tablets in 24 hours - Yellow tablets" />
        <additionalInstruction>
            <text value="Yellow tablets" />
        </additionalInstruction>
        <timing>
            <repeat>
                <frequency value="1" />
                <period value="4" />
                <periodUnit value="h" />
            </repeat>
        </timing>
        <asNeededBoolean value="true" />
        <doseQuantity>
            <value value="2" />
            <unit value="tablet" />
            <system value="http://snomed.info/sct" />
            <code value="428673006" />
        </doseQuantity>
        <maxDosePerPeriod>
            <numerator>
                <value value="6" />
                <unit value="tablet" />
                <system value="http://snomed.info/sct" />
                <code value="428673006" />
            </numerator>
            <denominator>
                <value value="24" />
                <unit value="hour" />
                <system value="http://unitsofmeasure.org" />
                <code value="h" />
            </denominator>
        </maxDosePerPeriod>
    </dosageInstruction>
</MedicationRequest>

{
    "resourceType": "MedicationRequest",
    "id": "859e5d8a-391a-4b2a-8f29-15e8c75180bb",
    "contained":  [
        {
            "resourceType": "Medication",
            "id": "internalMedicationIdentifer123abc",
            "code": {
                "coding":  [
                    {
                        "system": "http://snomed.info/sct",
                        "code": "3363411000001108",
                        "display": "Migraleve tablets (McNeil Products Ltd)"
                    }
                ]
            }
        }
    ],
    "status": "active",
    "intent": "order",
    "medicationReference": {
        "reference": "#internalMedicationIdentifer123abc",
        "display": "Migraleve tablets (McNeil Products Ltd)"
    },
    "subject": {
        "identifier": {
            "system": "https://fhir.nhs.uk/Id/nhs-number",
            "value": "9999999999"
        }
    },
    "dosageInstruction":  [
        {
            "sequence": 1,
            "text": "2 tablets - take once - as required when migraine occurs - Max dose 2 tablets in 24 hours - Pink tablet",
            "additionalInstruction":  [
                {
                    "text": "Pink tablets"
                }
            ],
            "timing": {
                "repeat": {
                    "count": 1
                }
            },
            "asNeededCodeableConcept": {
                "coding":  [
                    {
                        "system": "http://snomed.info/sct",
                        "code": "37796009",
                        "display": "Migraine"
                    }
                ]
            },
            "doseQuantity": {
                "value": 2,
                "unit": "tablet",
                "system": "http://snomed.info/sct",
                "code": "428673006"
            },
            "maxDosePerPeriod": {
                "numerator": {
                    "value": 2,
                    "unit": "tablet",
                    "system": "http://snomed.info/sct",
                    "code": "428673006"
                },
                "denominator": {
                    "value": 24,
                    "unit": "hour",
                    "system": "http://unitsofmeasure.org",
                    "code": "h"
                }
            }
        },
        {
            "sequence": 2,
            "text": "2 tablets - every 4 hours - as required - max dose 6 tablets in 24 hours - Yellow tablets",
            "additionalInstruction":  [
                {
                    "text": "Yellow tablets"
                }
            ],
            "timing": {
                "repeat": {
                    "frequency": 1,
                    "period": 4,
                    "periodUnit": "h"
                }
            },
            "asNeededBoolean": true,
            "doseQuantity": {
                "value": 2,
                "unit": "tablet",
                "system": "http://snomed.info/sct",
                "code": "428673006"
            },
            "maxDosePerPeriod": {
                "numerator": {
                    "value": 6,
                    "unit": "tablet",
                    "system": "http://snomed.info/sct",
                    "code": "428673006"
                },
                "denominator": {
                    "value": 24,
                    "unit": "hour",
                    "system": "http://unitsofmeasure.org",
                    "code": "h"
                }
            }
        }
    ]
}
MedicationRequest.id[0]859e5d8a-391a-4b2a-8f29-15e8c75180bb
MedicationRequest.contained[0].id[0]internalMedicationIdentifer123abc
MedicationRequest.contained[0].code[0].coding[0].system[0]http://snomed.info/sct
MedicationRequest.contained[0].code[0].coding[0].code[0]3363411000001108
MedicationRequest.contained[0].code[0].coding[0].display[0]Migraleve tablets (McNeil Products Ltd)
MedicationRequest.status[0]active
MedicationRequest.intent[0]order
MedicationRequest.medication[0].reference[0]#internalMedicationIdentifer123abc
MedicationRequest.medication[0].display[0]Migraleve tablets (McNeil Products Ltd)
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].sequence[0]1
MedicationRequest.dosageInstruction[0].text[0]2 tablets - take once - as required when migraine occurs - Max dose 2 tablets in 24 hours - Pink tablet
MedicationRequest.dosageInstruction[0].additionalInstruction[0].text[0]Pink tablets
MedicationRequest.dosageInstruction[0].timing[0].repeat[0].count[0]1
MedicationRequest.dosageInstruction[0].asNeeded[0].coding[0].system[0]http://snomed.info/sct
MedicationRequest.dosageInstruction[0].asNeeded[0].coding[0].code[0]37796009
MedicationRequest.dosageInstruction[0].asNeeded[0].coding[0].display[0]Migraine
MedicationRequest.dosageInstruction[0].dose[0].value[0]2
MedicationRequest.dosageInstruction[0].dose[0].unit[0]tablet
MedicationRequest.dosageInstruction[0].dose[0].system[0]http://snomed.info/sct
MedicationRequest.dosageInstruction[0].dose[0].code[0]428673006
MedicationRequest.dosageInstruction[0].maxDosePerPeriod[0].numerator[0].value[0]2
MedicationRequest.dosageInstruction[0].maxDosePerPeriod[0].numerator[0].unit[0]tablet
MedicationRequest.dosageInstruction[0].maxDosePerPeriod[0].numerator[0].system[0]http://snomed.info/sct
MedicationRequest.dosageInstruction[0].maxDosePerPeriod[0].numerator[0].code[0]428673006
MedicationRequest.dosageInstruction[0].maxDosePerPeriod[0].denominator[0].value[0]24
MedicationRequest.dosageInstruction[0].maxDosePerPeriod[0].denominator[0].unit[0]hour
MedicationRequest.dosageInstruction[0].maxDosePerPeriod[0].denominator[0].system[0]http://unitsofmeasure.org
MedicationRequest.dosageInstruction[0].maxDosePerPeriod[0].denominator[0].code[0]h
MedicationRequest.dosageInstruction[1].sequence[0]2
MedicationRequest.dosageInstruction[1].text[0]2 tablets - every 4 hours - as required - max dose 6 tablets in 24 hours - Yellow tablets
MedicationRequest.dosageInstruction[1].additionalInstruction[0].text[0]Yellow tablets
MedicationRequest.dosageInstruction[1].timing[0].repeat[0].frequency[0]1
MedicationRequest.dosageInstruction[1].timing[0].repeat[0].period[0]4
MedicationRequest.dosageInstruction[1].timing[0].repeat[0].periodUnit[0]h
MedicationRequest.dosageInstruction[1].asNeeded[0]True
MedicationRequest.dosageInstruction[1].dose[0].value[0]2
MedicationRequest.dosageInstruction[1].dose[0].unit[0]tablet
MedicationRequest.dosageInstruction[1].dose[0].system[0]http://snomed.info/sct
MedicationRequest.dosageInstruction[1].dose[0].code[0]428673006
MedicationRequest.dosageInstruction[1].maxDosePerPeriod[0].numerator[0].value[0]6
MedicationRequest.dosageInstruction[1].maxDosePerPeriod[0].numerator[0].unit[0]tablet
MedicationRequest.dosageInstruction[1].maxDosePerPeriod[0].numerator[0].system[0]http://snomed.info/sct
MedicationRequest.dosageInstruction[1].maxDosePerPeriod[0].numerator[0].code[0]428673006
MedicationRequest.dosageInstruction[1].maxDosePerPeriod[0].denominator[0].value[0]24
MedicationRequest.dosageInstruction[1].maxDosePerPeriod[0].denominator[0].unit[0]hour
MedicationRequest.dosageInstruction[1].maxDosePerPeriod[0].denominator[0].system[0]http://unitsofmeasure.org
MedicationRequest.dosageInstruction[1].maxDosePerPeriod[0].denominator[0].code[0]h
MedicationRequest
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