Examples of use of Medication order archetype and associated cluster archetypes

ian.mcnicoll@openehr.org

Medication ordering/prescribing can be highly complex, particularly the combination of dose amounts and timing.

This document contains a number of worked examples which should help inform intended use of the medication order archetype and associated cluster archetypes.

The key archetypes used in the construction of medication orders are …

Other cluster archetypes are generally required e.g. Authorisation, dispensing details but these are omitted in these examples for clarity.

An example template which makes use of these archetypes can be viewed at

The following mindmap outlines the combination of Medication order archetype with its Cluster components, as used in the examples …

Open

Terminology is omitted for clarity but it would be expected in most examples, the 'Medication item' would be coded using a reference medication terminology such as RxNorm, dm+d, AMT etc. 

Examples are given for both dose-based and product-based prescribing 

Most examples define an equivalent 'parsable dose syntax' intended to carry a subset of dose amount and timing details, appropriate for transferring information between disparate systems. The examples shown are derived from a dose syntax developed by NHS Scotland.

Note that this syntax has no official status within openEHR and is shown here purely as an example.

Atenolol 40mg one tablet in the morning, indefinitely

Medication order

  Medication item: Atenolol 40mg tabs

  Parsable dose directions: "1 m"

  Dose direction..

    Direction sequence: 0

    Dose pattern..

      Pattern sequence: 0

      Dose amount: 1

      Dose unit: tablet

      Timing - daily..

        Named time event: in the morning

    Direction duration: Indefinitely 

Atenolol 40mg one tablet in the morning for 4 weeks

Medication order

  Medication item: Atenolol

  Route: oral

  Parsable dose directions: "40mg m"

  Dose direction..

    Dose pattern..

      Dose amount: 40

      Dose unit: mg

      Timing - daily..

        Named time event: in the morning

    Direction duration: 4 weeks

Paracetamol liquid oral 125mg/5ml 5-10ml up to every 4-6 hours as required for pain or fever; maximum 40ml in 24hrs 

Medication order

  Medication item: Paracetamol liquid 125mg/5ml

  Route: oral

  Parsable dose directions: "5-10ml ^4h/6h prn [40ml h24]"

  Dose direction..

    Dose pattern..

      Dose amount: 5-10

      Dose unit: ml

      Timing - daily..

        Interval: <= 4-6 hours

      As required: True

      As required criterion: "for pain or fever"

  Medication safety..

      Maximum dose..

        Maximum amount: 40

        Maximum amount dose unit: ml

      Allowed period: 24 hours

The 'up to' aspect of the dose interval is carried in the magnitude_status attribute of the DV_QUANTITY datatype of the openEHR reference model.

D. Tapered dose-based prescribing order

Enalapril - oral - 2.5mg once daily for 1 day, then 5mg once daily for 7 days, then 5 mg at 6pm and 10mg at 10pm, indefinitely 

Medication order..

  Medication item: Enalapril

  Route: oral

  Parsable dose directions: "2.5mg od:1d ;5mg od:7d ;5mg @1800 & 10mg @2200 :ind"

  Dose direction..

    Direction sequence: 0

    Dose pattern..

      Dose amount: 2.5

      Dose unit: mg

      Timing - daily..

        Frequency: 1/day

    Direction duration: 1 day

  Dose direction..

    Direction sequence: 1

    Dose pattern..

      Dose amount: 5

      Dose unit: mg

      Timing - daily..

        Frequency: 1/day

    Direction duration: 1 day

  Dose direction..

    Direction sequence: 2

    Dose pattern..

      Pattern sequence: 0

      Dose amount: 5

      Dose unit: mg

      Timing - daily..

        Specific time: 1800

    Dose pattern..

      Pattern sequence: 1

      Dose amount: 10

      Dose unit: mg

      Timing - daily..

        Specific time: 2200

    Direction duration: indefinitely

  Additional instruction: Avoid grapefruit 

Enalapril 2.5mg tablets; 1 tab at night for 2 days, then 1 tab morning and night for 5 days, then 4 tabs at night, indefinitely 

Medication order..

  Medication item: Enalapril 2.5mg tablet

  Parsable dose directions: "1 n:2d ;1 m+n:5d ; 4 n:ind"

  Dose direction..

    Direction sequence: 0

    Dose pattern..

      Dose amount: 1

      Dose unit: tab

      Timing - daily..

        Named time event: in the morning

    Direction duration: 2 day

  Dose direction..

    Direction sequence: 1

    Dose pattern..

      Dose amount: 1

      Dose unit: tab

      Timing - daily..

        Named time event: in the morning

        Named time event: at night

    Direction duration: 5 day

  Dose direction..

    Direction sequence: 2

    Dose pattern..

      Dose amount: 4

      Dose unit: tab

      Timing - daily..

        Named time event: at night

    Direction duration: indefinitely

  Additional instruction: Avoid grapefruit

E. Complex dose-based order with multiple dose patterns

Gabapentin – oral - 300mg at night for one day, then 300mg in the morning and at night for one day, then 300mg three times a day for one day, then 300mg in the morning, 300mg in the afternoon and 600mg at night for 4 days, then 600mg in the morning, 300mg in the afternoon and 600mg at night for 1 day, then 600mg three times a day indefinitely.

Medication order..

  Medication item: Gabapentin

  Route: oral

  Parsable dose directions: 300mg n:1d;300mg m+n:1d;300mg td:1d;300mg m+pm&600mg n:4d;600mg m&300mg a&600mg n;600mg td:ind"

  Dose direction..

    Direction sequence: 0

    Dose pattern..

      Dose amount: 300

      Dose unit: mg

      Timing - daily..

        Named time event: at night

    Direction duration: 1 day

  Dose direction..

    Direction sequence: 1

    Dose pattern..

      Dose amount: 300

      Dose unit: mg

      Timing - daily..

        Named time event: in the morning

        Named time event: at night

    Direction duration: 1 day

  Dose direction..

    Direction sequence: 2

    Dose pattern..

      Dose amount: 300

      Dose unit: mg

      Timing - daily..

        Frequency: 3 / day

    Direction duration: 1 day

  Dose direction..

    Direction sequence: 3

    Dose pattern..

      Pattern sequence: 0

      Dose amount: 300

      Dose unit: mg

      Timing - daily..

        Named time event: in the morning

        Named time event: in the afternoon

    Dose pattern..

      Pattern sequence: 1

      Dose amount: 600

      Dose unit: mg

      Timing - daily..

        Named time event: at night

    Direction duration: 4 day

    Dose direction..

      Direction sequence: 4

      Dose pattern..

        Pattern sequence: 0

        Dose amount: 600

        Dose unit: mg

        Timing - daily..

          Named time event: in the morning

        Dose pattern..

          Pattern sequence: 1

          Dose amount: 300

          Dose unit: mg

          Timing - daily..

            Named time event: in the afternoon

      Dose pattern..

        Pattern sequence: 2

        Dose amount: 600

        Dose unit: mg

        Timing - daily..

          Named time event: at night

      Direction duration: 1 day

    Dose direction..

      Direction sequence: 5

      Dose pattern..

        Dose amount: 600

        Dose unit: mg

        Timing - daily..

          Frequency: 3 / day

      Direction duration: indefinitely

Azithromycin - oral - 500 mg once daily three times a week (Mon Wed Fri) for 6 months

Medication order..

  Medication item: Azithromycin

    Route: oral

    Parsable dose directions: "500mg od:6m, tw"

    Dose direction..

      Direction sequence: 0

      Dose pattern..

        Dose amount: 500

        Dose unit: mg

        Timing - daily..

            Frequency: 1 / day

        Timing - repetition..

          Frequency: 3 / week

          Specific day of the week: Monday

          Specific day of the week: Wednesday

          Specific day of the week: Friday

      Direction duration: 6 m

Paracetamol 500mg tablet 1-2 tablets up to 4-6 hourly as required for knee pain from 1 Dec 2016 for 14 days [Maximum 8 tablets in 24 hrs]. Take with food. 

Medication order..

  Medication item: Paracetamol 500mg tablet

  Parsable dose directions: "1-2 ^h4\h6 prn:7d [8 h24]"

  Dose direction..

    Dose pattern..

      Dose amount: 1-2

      Dose unit: tablet

      Timing - daily..

          Interval: <= 4-6 hr

          As required: True

          As required condition: for knee pain

    Direction duration: indefinitely

  Medication safety..

      Maximum dose..

        Maximum amount: 8

        Maximum amount dose unit: tablets

      Allowed period: 24 hours

  Additional instruction: Take with food

  Order details..

    Order start date/time: 1 Dec 2016

 The 'up to' aspect of the dose interval is carried in the magnitude_status attribute of the DV_QUANTITY datatype of the openEHR reference model.

This is an example of a complex 'ad-hoc' infusion containing a defined ingredient (morphine), a product ingredient (penicillin) and a diluent (saline). 

The Medication item name must be generated by the prescriber to reflect the key components of the infusion mixture e.g. to appear on the prescription list or as a label on the infusion itself.

The parsable dose syntax does not cover this use-case and is therefore omitted.

100 mg Morphine liquid (10mg/ml) +  12g Benzylpenicillin (3g powder) in 100ml 0.9% Saline infusion given over 1 hour, starting immediately

Medication order..

  Medication item: 100mg Morphine + 12g Benzylpenicillin in 100ml 0.9% Saline infusion

  Preparation details..

    Substance form: Infusion liquid

    Category: Ad-hoc mixture

    Ingredient..

      Ingredient substance..

        Substance name: Morphine

        Category: Ingredient

        Substance form: liquid for infusion

        Strength amount: 10

        Strength unit: mg

        Diluent..

          Diluent amount: 1

          Diluent unit: ml

      Ingredient amount:10

      Ingredient amount unit: ml

      Role: Therapeutic

    Ingredient..

      Ingredient substance..

        Substance name: Benzylpenicillin powder for infusion (3g/1ml)

        Substance form: powder for infusion

        Category: Product

       Ingredient amount:12

       Ingredient amount unit: g

       Role: Therapeutic

    Ingredient..

      Ingredient substance..

        Substance name: 0.9% Saline infusion

        Substance form: infusion liquid

        Category: Product

      Ingredient amount:100

      Ingredient amount unit: ml

      Role: Diluent

  Dose direction..

    Dose pattern..

      Dose amount: 100

      Dose unit: ml

      Timing - daily..

          Named time event: immediately (stat)

      Dose administration duration: 1 hr

  Order details..

    Order start date/time: 1 July 2016