Dispense for Azithromycin (RxNorm Code) - in-progress with coded additionalInstructions

{
  "resourceType" : "MedicationDispense",
  "id" : "meddisp0326",
  "status" : "in-progress",
  "medication" : {
    "concept" : {
      "coding" : [{
        "system" : "http://www.nlm.nih.gov/research/umls/rxnorm",
        "code" : "226827",
        "display" : "azithromycin 500 MG Oral Tablet [Zithromax]"
      }]
    }
  },
  "subject" : {
    "reference" : "Patient/pat1",
    "display" : "Donald Duck"
  },
  "performer" : [{
    "actor" : {
      "reference" : "Practitioner/f006"
    }
  }],
  "authorizingPrescription" : [{
    "reference" : "MedicationRequest/medrx0313"
  }],
  "type" : {
    "coding" : [{
      "system" : "http://terminology.hl7.org/CodeSystem/v3-ActCode",
      "code" : "TF",
      "display" : "trial Fill"
    }]
  },
  "quantity" : {
    "value" : 5,
    "system" : "http://terminology.hl7.org/CodeSystem/v3-orderableDrugForm",
    "code" : "TAB"
  },
  "daysSupply" : {
    "value" : 5,
    "unit" : "Day",
    "system" : "http://unitsofmeasure.org",
    "code" : "d"
  },
  "whenPrepared" : "2015-01-15T10:20:00Z",
  "dosageInstruction" : [{
    "sequence" : 1,
    "text" : "500mg daily for 5 days",
    "additionalInstruction" : [{
      "coding" : [{
        "system" : "http://snomed.info/sct",
        "code" : "421984009",
        "display" : "Until finished - dosing instruction fragment (qualifier value)"
      }]
    }],
    "timing" : {
      "repeat" : {
        "frequency" : 1,
        "period" : 1,
        "periodUnit" : "d"
      }
    },
    "route" : {
      "coding" : [{
        "system" : "http://snomed.info/sct",
        "code" : "26643006",
        "display" : "Oral Route (qualifier value)"
      }]
    },
    "doseAndRate" : [{
      "type" : {
        "coding" : [{
          "system" : "http://terminology.hl7.org/CodeSystem/dose-rate-type",
          "code" : "ordered",
          "display" : "Ordered"
        }]
      },
      "doseQuantity" : {
        "value" : 500,
        "unit" : "mg",
        "system" : "http://unitsofmeasure.org",
        "code" : "mg"
      }
    }]
  }]
}