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.

Metformin 500mg tablets, initially 500 mg once daily for 1 week, dose to be taken with breakfast, then 500 mg twice daily for week, dose to be taken with breakfast and evening meal, then 500 mg 3 times a day, dose to be taken with breakfast, lunch and evening meal; maximum 2 g per day

Product-based prescription demonstrating sequential dosing schedules for an increasing dose. 
<MedicationRequest xmlns="http://hl7.org/fhir">
    <id value="921aa4f4-c84e-4bf6-bc86-279d53e28d76" />
    <contained>
        <Medication>
            <id value="med1" />
            <code>
                <coding>
                    <system value="http://snomed.info/sct" />
                    <code value="325278007" />
                    <display value="Metformin 500mg 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>
        <sequence value="1" />
        <timing>
            <repeat>
                <duration value="1" />
                <durationUnit value="wk" />
                <frequency value="1" />
                <period value="1" />
                <periodUnit value="d" />
                <when value="CM" />
            </repeat>
        </timing>
        <doseQuantity>
            <value value="500" />
            <unit value="milligram" />
            <system value="http://unitsofmeasure.org" />
            <code value="mg" />
        </doseQuantity>
        <maxDosePerPeriod>
            <numerator>
                <value value="2" />
                <unit value="gram" />
                <system value="http://unitsofmeasure.org" />
                <code value="g" />
            </numerator>
            <denominator>
                <value value="1" />
                <unit value="day" />
                <system value="http://unitsofmeasure.org" />
                <code value="d" />
            </denominator>
        </maxDosePerPeriod>
    </dosageInstruction>
    <dosageInstruction>
        <sequence value="2" />
        <timing>
            <repeat>
                <duration value="1" />
                <durationUnit value="wk" />
                <frequency value="2" />
                <period value="1" />
                <periodUnit value="d" />
                <when value="CM" />
                <when value="CV" />
            </repeat>
        </timing>
        <doseQuantity>
            <value value="500" />
            <unit value="milligram" />
            <system value="http://unitsofmeasure.org" />
            <code value="mg" />
        </doseQuantity>
        <maxDosePerPeriod>
            <numerator>
                <value value="2" />
                <unit value="gram" />
                <system value="http://unitsofmeasure.org" />
                <code value="g" />
            </numerator>
            <denominator>
                <value value="1" />
                <unit value="day" />
                <system value="http://unitsofmeasure.org" />
                <code value="d" />
            </denominator>
        </maxDosePerPeriod>
    </dosageInstruction>
    <dosageInstruction>
        <sequence value="3" />
        <timing>
            <repeat>
                <duration value="1" />
                <durationUnit value="wk" />
                <frequency value="2" />
                <period value="1" />
                <periodUnit value="d" />
                <when value="CM" />
                <when value="CV" />
            </repeat>
        </timing>
        <doseQuantity>
            <value value="500" />
            <unit value="milligram" />
            <system value="http://unitsofmeasure.org" />
            <code value="mg" />
        </doseQuantity>
        <maxDosePerPeriod>
            <numerator>
                <value value="2" />
                <unit value="gram" />
                <system value="http://unitsofmeasure.org" />
                <code value="g" />
            </numerator>
            <denominator>
                <value value="1" />
                <unit value="day" />
                <system value="http://unitsofmeasure.org" />
                <code value="d" />
            </denominator>
        </maxDosePerPeriod>
    </dosageInstruction>
    <dosageInstruction>
        <sequence value="4" />
        <timing>
            <repeat>
                <duration value="1" />
                <durationUnit value="wk" />
                <frequency value="3" />
                <period value="1" />
                <periodUnit value="d" />
                <when value="CM" />
                <when value="CV" />
                <when value="CD" />
            </repeat>
        </timing>
        <doseQuantity>
            <value value="500" />
            <unit value="milligram" />
            <system value="http://unitsofmeasure.org" />
            <code value="mg" />
        </doseQuantity>
        <maxDosePerPeriod>
            <numerator>
                <value value="2" />
                <unit value="gram" />
                <system value="http://unitsofmeasure.org" />
                <code value="g" />
            </numerator>
            <denominator>
                <value value="1" />
                <unit value="day" />
                <system value="http://unitsofmeasure.org" />
                <code value="d" />
            </denominator>
        </maxDosePerPeriod>
    </dosageInstruction>
</MedicationRequest>

{
    "resourceType": "MedicationRequest",
    "id": "921aa4f4-c84e-4bf6-bc86-279d53e28d76",
    "contained":  [
        {
            "resourceType": "Medication",
            "id": "med1",
            "code": {
                "coding":  [
                    {
                        "system": "http://snomed.info/sct",
                        "code": "325278007",
                        "display": "Metformin 500mg tablets"
                    }
                ]
            }
        }
    ],
    "status": "active",
    "intent": "order",
    "medicationReference": {
        "reference": "#med1"
    },
    "subject": {
        "identifier": {
            "system": "https://fhir.nhs.uk/Id/nhs-number",
            "value": "9999999999"
        }
    },
    "dosageInstruction":  [
        {
            "sequence": 1,
            "timing": {
                "repeat": {
                    "duration": 1,
                    "durationUnit": "wk",
                    "frequency": 1,
                    "period": 1,
                    "periodUnit": "d",
                    "when":  [
                        "CM"
                    ]
                }
            },
            "doseQuantity": {
                "value": 500,
                "unit": "milligram",
                "system": "http://unitsofmeasure.org",
                "code": "mg"
            },
            "maxDosePerPeriod": {
                "numerator": {
                    "value": 2,
                    "unit": "gram",
                    "system": "http://unitsofmeasure.org",
                    "code": "g"
                },
                "denominator": {
                    "value": 1,
                    "unit": "day",
                    "system": "http://unitsofmeasure.org",
                    "code": "d"
                }
            }
        },
        {
            "sequence": 2,
            "timing": {
                "repeat": {
                    "duration": 1,
                    "durationUnit": "wk",
                    "frequency": 2,
                    "period": 1,
                    "periodUnit": "d",
                    "when":  [
                        "CM",
                        "CV"
                    ]
                }
            },
            "doseQuantity": {
                "value": 500,
                "unit": "milligram",
                "system": "http://unitsofmeasure.org",
                "code": "mg"
            },
            "maxDosePerPeriod": {
                "numerator": {
                    "value": 2,
                    "unit": "gram",
                    "system": "http://unitsofmeasure.org",
                    "code": "g"
                },
                "denominator": {
                    "value": 1,
                    "unit": "day",
                    "system": "http://unitsofmeasure.org",
                    "code": "d"
                }
            }
        },
        {
            "sequence": 3,
            "timing": {
                "repeat": {
                    "duration": 1,
                    "durationUnit": "wk",
                    "frequency": 2,
                    "period": 1,
                    "periodUnit": "d",
                    "when":  [
                        "CM",
                        "CV"
                    ]
                }
            },
            "doseQuantity": {
                "value": 500,
                "unit": "milligram",
                "system": "http://unitsofmeasure.org",
                "code": "mg"
            },
            "maxDosePerPeriod": {
                "numerator": {
                    "value": 2,
                    "unit": "gram",
                    "system": "http://unitsofmeasure.org",
                    "code": "g"
                },
                "denominator": {
                    "value": 1,
                    "unit": "day",
                    "system": "http://unitsofmeasure.org",
                    "code": "d"
                }
            }
        },
        {
            "sequence": 4,
            "timing": {
                "repeat": {
                    "duration": 1,
                    "durationUnit": "wk",
                    "frequency": 3,
                    "period": 1,
                    "periodUnit": "d",
                    "when":  [
                        "CM",
                        "CV",
                        "CD"
                    ]
                }
            },
            "doseQuantity": {
                "value": 500,
                "unit": "milligram",
                "system": "http://unitsofmeasure.org",
                "code": "mg"
            },
            "maxDosePerPeriod": {
                "numerator": {
                    "value": 2,
                    "unit": "gram",
                    "system": "http://unitsofmeasure.org",
                    "code": "g"
                },
                "denominator": {
                    "value": 1,
                    "unit": "day",
                    "system": "http://unitsofmeasure.org",
                    "code": "d"
                }
            }
        }
    ]
}
MedicationRequest.id[0]921aa4f4-c84e-4bf6-bc86-279d53e28d76
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]325278007
MedicationRequest.contained[0].code[0].coding[0].display[0]Metformin 500mg 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].sequence[0]1
MedicationRequest.dosageInstruction[0].timing[0].repeat[0].duration[0]1
MedicationRequest.dosageInstruction[0].timing[0].repeat[0].durationUnit[0]wk
MedicationRequest.dosageInstruction[0].timing[0].repeat[0].frequency[0]1
MedicationRequest.dosageInstruction[0].timing[0].repeat[0].period[0]1
MedicationRequest.dosageInstruction[0].timing[0].repeat[0].periodUnit[0]d
MedicationRequest.dosageInstruction[0].timing[0].repeat[0].when[0]CM
MedicationRequest.dosageInstruction[0].dose[0].value[0]500
MedicationRequest.dosageInstruction[0].dose[0].unit[0]milligram
MedicationRequest.dosageInstruction[0].dose[0].system[0]http://unitsofmeasure.org
MedicationRequest.dosageInstruction[0].dose[0].code[0]mg
MedicationRequest.dosageInstruction[0].maxDosePerPeriod[0].numerator[0].value[0]2
MedicationRequest.dosageInstruction[0].maxDosePerPeriod[0].numerator[0].unit[0]gram
MedicationRequest.dosageInstruction[0].maxDosePerPeriod[0].numerator[0].system[0]http://unitsofmeasure.org
MedicationRequest.dosageInstruction[0].maxDosePerPeriod[0].numerator[0].code[0]g
MedicationRequest.dosageInstruction[0].maxDosePerPeriod[0].denominator[0].value[0]1
MedicationRequest.dosageInstruction[0].maxDosePerPeriod[0].denominator[0].unit[0]day
MedicationRequest.dosageInstruction[0].maxDosePerPeriod[0].denominator[0].system[0]http://unitsofmeasure.org
MedicationRequest.dosageInstruction[0].maxDosePerPeriod[0].denominator[0].code[0]d
MedicationRequest.dosageInstruction[1].sequence[0]2
MedicationRequest.dosageInstruction[1].timing[0].repeat[0].duration[0]1
MedicationRequest.dosageInstruction[1].timing[0].repeat[0].durationUnit[0]wk
MedicationRequest.dosageInstruction[1].timing[0].repeat[0].frequency[0]2
MedicationRequest.dosageInstruction[1].timing[0].repeat[0].period[0]1
MedicationRequest.dosageInstruction[1].timing[0].repeat[0].periodUnit[0]d
MedicationRequest.dosageInstruction[1].timing[0].repeat[0].when[0]CM
MedicationRequest.dosageInstruction[1].timing[0].repeat[0].when[1]CV
MedicationRequest.dosageInstruction[1].dose[0].value[0]500
MedicationRequest.dosageInstruction[1].dose[0].unit[0]milligram
MedicationRequest.dosageInstruction[1].dose[0].system[0]http://unitsofmeasure.org
MedicationRequest.dosageInstruction[1].dose[0].code[0]mg
MedicationRequest.dosageInstruction[1].maxDosePerPeriod[0].numerator[0].value[0]2
MedicationRequest.dosageInstruction[1].maxDosePerPeriod[0].numerator[0].unit[0]gram
MedicationRequest.dosageInstruction[1].maxDosePerPeriod[0].numerator[0].system[0]http://unitsofmeasure.org
MedicationRequest.dosageInstruction[1].maxDosePerPeriod[0].numerator[0].code[0]g
MedicationRequest.dosageInstruction[1].maxDosePerPeriod[0].denominator[0].value[0]1
MedicationRequest.dosageInstruction[1].maxDosePerPeriod[0].denominator[0].unit[0]day
MedicationRequest.dosageInstruction[1].maxDosePerPeriod[0].denominator[0].system[0]http://unitsofmeasure.org
MedicationRequest.dosageInstruction[1].maxDosePerPeriod[0].denominator[0].code[0]d
MedicationRequest.dosageInstruction[2].sequence[0]3
MedicationRequest.dosageInstruction[2].timing[0].repeat[0].duration[0]1
MedicationRequest.dosageInstruction[2].timing[0].repeat[0].durationUnit[0]wk
MedicationRequest.dosageInstruction[2].timing[0].repeat[0].frequency[0]2
MedicationRequest.dosageInstruction[2].timing[0].repeat[0].period[0]1
MedicationRequest.dosageInstruction[2].timing[0].repeat[0].periodUnit[0]d
MedicationRequest.dosageInstruction[2].timing[0].repeat[0].when[0]CM
MedicationRequest.dosageInstruction[2].timing[0].repeat[0].when[1]CV
MedicationRequest.dosageInstruction[2].dose[0].value[0]500
MedicationRequest.dosageInstruction[2].dose[0].unit[0]milligram
MedicationRequest.dosageInstruction[2].dose[0].system[0]http://unitsofmeasure.org
MedicationRequest.dosageInstruction[2].dose[0].code[0]mg
MedicationRequest.dosageInstruction[2].maxDosePerPeriod[0].numerator[0].value[0]2
MedicationRequest.dosageInstruction[2].maxDosePerPeriod[0].numerator[0].unit[0]gram
MedicationRequest.dosageInstruction[2].maxDosePerPeriod[0].numerator[0].system[0]http://unitsofmeasure.org
MedicationRequest.dosageInstruction[2].maxDosePerPeriod[0].numerator[0].code[0]g
MedicationRequest.dosageInstruction[2].maxDosePerPeriod[0].denominator[0].value[0]1
MedicationRequest.dosageInstruction[2].maxDosePerPeriod[0].denominator[0].unit[0]day
MedicationRequest.dosageInstruction[2].maxDosePerPeriod[0].denominator[0].system[0]http://unitsofmeasure.org
MedicationRequest.dosageInstruction[2].maxDosePerPeriod[0].denominator[0].code[0]d
MedicationRequest.dosageInstruction[3].sequence[0]4
MedicationRequest.dosageInstruction[3].timing[0].repeat[0].duration[0]1
MedicationRequest.dosageInstruction[3].timing[0].repeat[0].durationUnit[0]wk
MedicationRequest.dosageInstruction[3].timing[0].repeat[0].frequency[0]3
MedicationRequest.dosageInstruction[3].timing[0].repeat[0].period[0]1
MedicationRequest.dosageInstruction[3].timing[0].repeat[0].periodUnit[0]d
MedicationRequest.dosageInstruction[3].timing[0].repeat[0].when[0]CM
MedicationRequest.dosageInstruction[3].timing[0].repeat[0].when[1]CV
MedicationRequest.dosageInstruction[3].timing[0].repeat[0].when[2]CD
MedicationRequest.dosageInstruction[3].dose[0].value[0]500
MedicationRequest.dosageInstruction[3].dose[0].unit[0]milligram
MedicationRequest.dosageInstruction[3].dose[0].system[0]http://unitsofmeasure.org
MedicationRequest.dosageInstruction[3].dose[0].code[0]mg
MedicationRequest.dosageInstruction[3].maxDosePerPeriod[0].numerator[0].value[0]2
MedicationRequest.dosageInstruction[3].maxDosePerPeriod[0].numerator[0].unit[0]gram
MedicationRequest.dosageInstruction[3].maxDosePerPeriod[0].numerator[0].system[0]http://unitsofmeasure.org
MedicationRequest.dosageInstruction[3].maxDosePerPeriod[0].numerator[0].code[0]g
MedicationRequest.dosageInstruction[3].maxDosePerPeriod[0].denominator[0].value[0]1
MedicationRequest.dosageInstruction[3].maxDosePerPeriod[0].denominator[0].unit[0]day
MedicationRequest.dosageInstruction[3].maxDosePerPeriod[0].denominator[0].system[0]http://unitsofmeasure.org
MedicationRequest.dosageInstruction[3].maxDosePerPeriod[0].denominator[0].code[0]d
MedicationRequest
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