HL7AU - FHIR WG : Analysis of how brand and generic name can be recorded in the HL7 AU Base medication profiles

This is about how medications are identified in Medication, MedicationRequest, MedicationAdministration, MedicationDispense, MedicationStatement, about whether extensions are needed.

Table of different combinations of brand and generic name in descriptions of a medication.

I assume that when a system is creating one of the FHIR medication resources the source system will have zero, one or two text strings or code values to identify the medication. For example a brand name code and a generic name code.

This table lists the options around whether the information is in text or code, whether it is flagged as for a generic or branded item, and whether zero, one or two items (text strings or codes) are provided. It then provides mappings to the HL7 AU Medication profile for the combinations that have been identified as being used. Combinations not identified as used are coded with reasons for not being used.

How to read Source system columns

Case #2 says that one item for medication from the source system is uncoded text marked as being a brand name

Case #7 says that one item for medication from the source system is a code with no information about being a brand or generic name

Case #17 says that one item for medication from the source system is uncoded text marked as being a generic name and a second item is a code marked as being a brand name

Policy

Do not use an extension (such as medication-brand-name) when a core element (such as code.text) is suitable.

Assumptions

• Some source systems can distinguish brand from generic, but are too coarse to use the values in medication-type
• Alternate values of CodeableConcept.coding are meant to be alternate codes for the same thing, not represent a classification hierarchy for that thing. The part of the classification hierarchy relevant to the medication needs to be recorded in a different element. 

Key

Values used in the columns item 1 and item 2

• bn = the item is marked as a brand name
• gn = the item is marked as a generic name
• ni = no information about whether the item is a brand or generic name
• NA = not applicable

Values in the used column

• yes = is used
• no = is not used
• NA = not applicable
• ? = unknown whether used

Values in the reason not used column, and row colours

New extensions

• code.med-item-type - like existing medication-type extension with the available values being "branded" and "unbranded". Allows suitably grained classification.
• relevant-generic-medication-item - semantics: a relevant unbranded medication item for the branded item, same structure as code with extension for code.med-item-type