Complex medication treatments

I can’t find the correct way for prescribing some complex treatments with FHIR.
For example, an Oncology treatment which has some medications mixed. Even simpler, a medication with diluent.

I’m always centered in the MedicationOrder resource.
The field Medication has 1…1 Cardinality so I can’t find the way.
Could I declare a List of MedicationOrder for relate them? In this case, some fields like dateWritten, dateEnded, prescriber… and so many more, will be repeated. Actually, they are not different prescriptions.
The administration confirmation for this treatment should be also only one resource because we have a mixture of medications…

Could you help me with this workaround?

Many thanks

The intent is that you would use the Medication resource to specify the mixture

In this case I will be losing information about prescribed doses for each one of them.
I can’t find a correct way to link all medications without an extension in medicationOrder similar to [{Medication, dosageInstruction}].
I think it is not easy to reflect this case without extensions, but I’m trying to avoid them.

Well, I think that there’s 2 different things here - a medication with a mixture, like a diluent - that’s where the medication resource comes into play. The other is where you have multiple different things to administer in a coordinated treatment plan - so a set of medication orders, with a care plan coordinating them - at least, that’s how I think it plays out in FHIR

The proposal is for the MedicationOrder to align with the workflow Request pattern, which means that there can be a shared requisition identifier on a bunch of related orders. However, each order is still treated as independent in terms of status and subsequent manipulation.

We have a similar situation in our Dialysis Clinics. We administer a Dialysis Order and also some PRN meds. The Dialysis Order itself contains several medications, labs, as well as the actual dialysis treatment. We chose to use Procedure and Procedure Request to capture all that. Not sure if it that makes sense for you.