Examples of use of Medication order archetype and associated cluster archetypes
Ian McNicoll, openEHR
Introduction
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.
Â
The key archetypes used in the construction of medication orders are …
Medication order: http://openehr.org/ckm/#showArchetype_1013.1.1445
Medication substance: http://openehr.org/ckm/#showArchetype_1013.1.2368
Timing - daily: http://openehr.org/ckm/#showArchetype_1013.1.2245
Timing - repetition: http://openehr.org/ckm/#showArchetype_1013.1.2246
Â
Other cluster archetypes are generally required e.g. Authorisation, dispensing details but these are omitted in these examples for clarity.
Â
An example template which makes use of these archetypes can be viewed at
ePrescription (FHIR): http://openehr.org/ckm/#showTemplate_1013.26.80
Â
The following mindmap outlines the combination of Medication order archetype with its Cluster components, as used in the examples …
Overview of Medication order and related cluster archetypes.
Â
Use of terminology
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.Â
Dose and Product-based prescribing
Examples are given for both dose-based and product-based prescribingÂ
Dose-based prescribing
The drug name (Medication item) is expressed as a chemical agent and the dose amount is generally expressed as an SI unit. Route is generally specified rather than form.
e.g. Atenolol - oral - 40mg twice daily
Product-based prescribing
The drug name (Medication item) is expressed as a specific manufactured product (generic or otherwise) and the dose is generally expressed as a dose unit - tablets, capsules, drops, puffs. Form is generally not specified since it is carried in the product name
e.g. Atenolol 40mg tabs - 1 tablet twice daily
Â
Parsable dose syntax examples
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.
A. Simple product-based medication order
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: IndefinitelyÂ
B. Simple dose-based medication order
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
C. 'As required' order with an 'up to' interval timing and a maximal daily dose
Paracetamol liquid oral 125mg/5ml 5-10ml up to every 4-6 hours as required for pain or fever; maximum 40ml in 24hrsÂ
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
Notes
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, indefinitelyÂ
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 grapefruitÂ
D. Tapered product-based prescribing orderÂ
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, indefinitelyÂ
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
Â
Â
Â
E. Complex dose-based order with multiple dose patterns
Â
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.
Â
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
F. Dose-based medication order with use of 'timing repetitions'
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
G. 'As required' product-based order with specified start date
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.Â
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
Notes
 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.
H. Complex ‘Ad-hoc’ infusion with administration durationÂ
This is an example of a complex 'ad-hoc' infusion containing a defined ingredient (morphine), a product ingredient (penicillin) and a diluent (saline).Â
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.
Â
100 mg Morphine liquid (10mg/ml) +Â 12g Benzylpenicillin (3g powder) in 100ml 0.9% Saline infusion given over 1 hour, starting immediately
Â
Â
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
Â