Request for Intravenous Dopamine - Weight based calculation with rateQuantity

{
  "resourceType" : "MedicationRequest",
  "id" : "medrx0336",
  "contained" : [{
    "resourceType" : "Medication",
    "id" : "med0336",
    "doseForm" : {
      "coding" : [{
        "system" : "http://snomed.info/sct",
        "code" : "385219001",
        "display" : "Solution for injection"
      }],
      "text" : "Solution for injection"
    },
    "ingredient" : [{
      "item" : {
        "concept" : {
          "coding" : [{
            "system" : "http://www.nlm.nih.gov/research/umls/rxnorm",
            "code" : "1114879",
            "display" : "dopamine hydrochloride 40 MG/ML"
          }]
        }
      },
      "strengthRatio" : {
        "numerator" : {
          "value" : 400,
          "system" : "http://unitsofmeasure.org",
          "code" : "mg"
        },
        "denominator" : {
          "value" : 500,
          "system" : "http://unitsofmeasure.org",
          "code" : "mL"
        }
      }
    },
    {
      "item" : {
        "concept" : {
          "coding" : [{
            "system" : "http://hl7.org/fhir/sid/ndc",
            "code" : "0264-7510-10",
            "display" : "DEXTROSE, 24 CONTAINER in 1 CASE (0264-7510-10) > 500 mL in 1 CONTAINER (package)"
          }],
          "text" : "Dextrose 5% injection USP"
        }
      },
      "strengthRatio" : {
        "numerator" : {
          "value" : 5,
          "system" : "http://unitsofmeasure.org",
          "code" : "g"
        },
        "denominator" : {
          "value" : 100,
          "system" : "http://unitsofmeasure.org",
          "code" : "mL"
        }
      }
    }]
  }],
  "identifier" : [{
    "use" : "official",
    "system" : "http://www.bmc.nl/portal/prescriptions",
    "value" : "12345689"
  }],
  "status" : "completed",
  "intent" : "order",
  "medication" : {
    "reference" : {
      "reference" : "#med0336",
      "display" : "Dopamine 400mg in 500mL D5W"
    }
  },
  "subject" : {
    "reference" : "Patient/pat1",
    "display" : "Donald Duck"
  },
  "supportingInformation" : [{
    "reference" : "Observation/example"
  }],
  "authoredOn" : "2015-01-15",
  "requester" : {
    "reference" : "Practitioner/f007",
    "display" : "Patrick Pump"
  },
  "dosageInstruction" : [{
    "sequence" : 1,
    "text" : "Dopamine 4mcg/kg/min",
    "timing" : {
      "repeat" : {
        "duration" : 33.33,
        "durationUnit" : "h"
      }
    },
    "route" : {
      "coding" : [{
        "system" : "http://snomed.info/sct",
        "code" : "47625008",
        "display" : "Intravenous route"
      }]
    },
    "doseAndRate" : [{
      "type" : {
        "coding" : [{
          "system" : "http://terminology.hl7.org/CodeSystem/dose-rate-type",
          "code" : "ordered",
          "display" : "Ordered"
        }]
      },
      "rateQuantity" : {
        "value" : 4,
        "unit" : "ug/kg/min",
        "system" : "http://unitsofmeasure.org"
      }
    }]
  }]
}