Medication: key+value pairs for any other information

[rlindstrm]

Question from Giorgio: do we want to have an extension for Medication with a key and value to allow any other kind of information about Medication. Key would probably be CodeableConcept, value can be anything.

[rlindstrm]

Logical model updated. Extension profiled. Jira ticket to HL7 Pharmacy: https://jira.hl7.org/browse/FHIR-46413

One question to discuss: what are the allowed data types for characteristic.value. Other similar profiles have different sets of allowed data types. IHE extension does not specify data types for now, so everything is allowed.

[rlindstrm]

Comment from Kari Heinonen: I fail to see a clear pattern in value[x] datatype choices available for general use, “additional IG-defined info”, property/characteristic/etc. elements appearing in number of FHIR resources. As you noted there's a lot of (subtle or not) variety and the "skipped" datatypes don't always make any sense. MedicinalProductDefinition one is missing some datatypes that feel quite "basic":

• string (curiously included in MedicationKnowledge one though)
• decimal (or is it seen as being covered by Quantity ?)
• reference (to Any with explanation/qualification given by .type part of key-value pair; also would eliminate need for the Jira ticket to expand Medication.definition to cover other Definitionals ?)
• Period and Range (can't understand why not included ?)

Logically should also include datatypes used in Definitional bespoke "attribute value" elements:

• Ratio
• RatioRange
• Duration (? linked to need for Time)

Is there a use at Medication level for:

• Time or DateTime (on the other hand the key-value extension should be usable in other contexts too where Time is more relevant)
• identifier (that would then supposedly really apply to something other, as indicated by .type, than Med itself ? But identifier can already carry the "typing" info inside it so likely redundant datatype for characteristics ?)