CH EMED (R4)
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CH EMED (R4), published by HL7 Switzerland. This guide is not an authorized publication; it is the continuous build for version 5.0.0-ci-build built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/hl7ch/ch-emed/ and changes regularly. See the Directory of published versions

Dosage

Overview

This implementation guide currently describes the normal dosing and the split dosing. The normal dosing can be given in a structured form and/or as narrative text. If possible, the structured form should be provided. In case structured dosage instructions are not provided or for complex dosages, the dosage can be represented using narrative text.

In the structured form, the format 1-1-1-1, meaning the administration time in the morning, at noon, in the evening, at night, is supported. For normal dosing, the dose quantity is the same at the defined administration times (e.g. 1-0-0-0, 1-0-1-0). For split dosing, the dose quantity varies depending on the administration time (e.g. 1-0-2-0, 2-1-2-0).

The dosage instruction is based on the 6.3.4.6 Dosage Instructions Content Module (1.3.6.1.4.1.19376.1.9.1.3.6) in the IHE Pharmacy Technical Framework Supplement: Community Prescription (PRE).

Timing

Start and Stop

The (outer) bounds of the treatment period are mapped as start and/or end dates (with or without time).

Timing Event

For the representation of the time of administration according to the 1-1-1-1 scheme, the values MORN-NOON-EVE-NIGHT from the ValueSet EventTiming are highly recommended for the Swiss use.

Dose and Rate

The amount of medication administered according to the 1-1-1-1 scheme is represented with SNOMED CT or UCUM codes, which are defined in the ValueSet UnitCode.

In Reserve

There is an option to indicate whether the medication is taken only as needed (e.g., when pain occurs) as part of the specified dosing schedule. If it is a reserve medication, the dosage indicated is the maximum dosage the patient may take.

Route of Administration

A code for specifying the route of administration into or onto a patient's body comes from the ValueSet EDQM - RouteOfAdministration.

Patient Instruction

Instructions to the patient regarding the administration of the medication, e.g. taking with food. The instructions are in a patient understandable language.
Additionally, if no structured dosage instructions are provided or the dosage is complex, the dosage can be represented here using narrative text.

The current FHIR representation of the dosage within the defined documents for the exchange of medication information is shown here. The use case and the corresponding examples contain the so-called normal and split dosing.

The implementers are asked here to communicate other dosage forms that are relevant in their environment, so that any expansions can be made in a next step. Or feedback on whether these dosage forms are sufficient would be helpful.

Please add your feedback via the 'Propose a change'-link in the footer of the page.

 

Normal Dosing

The normal dosing is represented using one dosage element. The dosage can be in a structured form, narrative text, or a combination of both.

Normal Dosing - Structured

Dosing example based on the use case step 2-5:

Dosage morning Dosage noon Dosage evening Dosage night Unit In reserve Route of administration Start and/or end date Patient instruction
1 0 1 0 tablet as needed oral 04.02.2012 - Take with food 
  "dosage" : [
    {
      "patientInstruction" : "Take with food",
      "timing" : {
        "repeat" : {
          "boundsPeriod" : {
              "start" : "2012-02-04"
          },
          "when" : [
            "MORN",
            "EVE"
          ]
        }
      },
      "asNeededBoolean" : true,
      "route" : {
        "coding" : [
          {
            "system" : "urn:oid:0.4.0.127.0.16.1.1.2.1",
            "code" : "20053000",
            "display" : "Oral use"
          }
        ]
      },
      "doseAndRate" : [
        {
          "doseQuantity" : {
            "value" : 1,
            "unit" : "Tablet (unit of presentation)",
            "system" : "http://snomed.info/sct",
            "code" : "732936001"
          }
        }
      ]
    }
  ]

Normal Dosing - Narrative

The narrative dosage instructions is represented in the Dosage.patientInstruction element.

Dosing example where no structured form is provided:

Dosage morning Dosage noon Dosage evening Dosage night Unit In reserve Route of administration Start and/or end date Patient instruction
                Take 2 tablets daily as usual before dinner with a little water, reduce the dosage one week before surgery to 1 tablet daily. 
  "dosage" : [
    {
      "patientInstruction" : "Take 2 tablets daily as usual before dinner with a little water, reduce the dosage one week before surgery to 1 tablet daily.",
    }
  ]

Normal Dosing - Structured & Narrative

Dosing example with the structured form and supplemented by the narrative text:

Dosage morning Dosage noon Dosage evening Dosage night Unit In reserve Route of administration Start and/or end date Patient instruction
            oral 01.09.2022 - 14.09.2022 Take one tablet in the morning and one in the evening on even days. On odd days, take half a tablet in the morning and half in the evening. 
  "dosage" : [
    {
      "patientInstruction" : "Take one tablet in the morning and one in the evening on even days. On odd days, take half a tablet in the morning and half in the evening.",
      "timing" : {
        "repeat" : {
          "boundsPeriod" : {
            "start" : "2022-09-01",
            "end" : "2022-09-14"
          },
          "when" : [
            "MORN",
            "EVE"
          ]
        }
      },
      "route" : {
        "coding" : [
          {
            "system" : "urn:oid:0.4.0.127.0.16.1.1.2.1",
            "code" : "20053000",
            "display" : "Oral use"
          }
        ]
      }
    }
  ]

Split Dosing

The split dosing differs from the normal dosing in that the dosage element is repeated. In contrast to normal dosing, where the dosage element can occur once, the dosage element can be repeated n times in split dosing. The order of the dosage instructions is defined by the required element Dosage.sequence.
The information, which is the same for all dosage elements (patientInstruction, timing.repeat.boundsPeriod, asNeeded, route) is mapped in the first dosage element.

Dosing example based on the use case step 2-3:

Dosage morning Dosage noon Dosage evening Dosage night Unit In reserve Route of administration Start and/or end date Patient instruction
1 0 0.5 0 tablet   oral 04.02.2012 - Take with food 
  "dosage" : [
    {
      "sequence" : 1,
      "patientInstruction" : "Take with food",
      "timing" : {
        "repeat" : {
          "boundsPeriod" : {
            "start" : "2012-02-04"
          },
          "when" : [
            "MORN"
          ]
        }
      },
      "route" : {
        "coding" : [
          {
            "system" : "urn:oid:0.4.0.127.0.16.1.1.2.1",
            "code" : "20053000",
            "display" : "Oral use"
          }
        ]
      },
      "doseAndRate" : [
        {
          "doseQuantity" : {
            "value" : 1,
            "unit" : "Tablet (unit of presentation)",
            "system" : "http://snomed.info/sct",
            "code" : "732936001"
          }
        }
      ]
    },
    {
      "sequence" : 2,
      "timing" : {
        "repeat" : {
          "when" : [
            "EVE"
          ]
        }
      },
      "doseAndRate" : [
        {
          "doseQuantity" : {
            "value" : 0.5,
            "unit" : "Tablet (unit of presentation)",
            "system" : "http://snomed.info/sct",
            "code" : "732936001"
          }
        }
      ]
    }
  ]

Profiles

Definition of the dosage (base dosage entry 1..1):

Definition of the split dosage (additional dosage entry 0..*):