Introduction
Medications are central to most healthcare encounters. FHIR provides several resources to represent different aspects of medication management, from ordering to administration tracking.
Key Medication Resources
| Resource | Purpose |
|---|---|
| MedicationRequest | An order or prescription for a medication |
| MedicationStatement | A record of medication a patient is taking |
| MedicationAdministration | Documentation of medication administered to a patient |
| MedicationDispense | Medication prepared and delivered by a pharmacy |
| MedicationKnowledge | Reference information about a medication (formulary, guidelines) |
API Conventions for Medication Resources
Across all medication resources, ESUS accepts primary references as flat string id fields:
| Reference in FHIR | Body field in ESUS |
|---|---|
subject: { reference: "Patient/<id>" } | subjectId: "<uuid>" |
encounter: { reference: "Encounter/<id>" } | encounterId: "<uuid>" |
requester: { reference: "Practitioner/<id>" } | requesterId: "<uuid>" |
request: { reference: "MedicationRequest/<id>" } | requestId: "<uuid>" |
Nested FHIR reference objects (performer arrays, authorizingPrescription, etc.) continue to use the standard { reference: "Type/<uuid>" } shape. All ids are raw UUIDs (v4).
MedicationRequest Structure
The MedicationRequest is the most commonly used resource for prescribing:
{
"status": "active",
"intent": "order",
"medicationCodeableConcept": {
"coding": [{
"system": "http://www.nlm.nih.gov/research/umls/rxnorm",
"code": "197361",
"display": "Amoxicillin 500mg"
}]
},
"subjectId": "3fa85f64-5717-4562-b3fc-2c963f66afa6",
"requesterId": "a7b1c2d3-e4f5-6789-abcd-ef0123456789",
"authoredOn": "2026-04-21"
}
Important Fields
- status:
active,on-hold,completed,cancelled,stopped,draft,entered-in-error,unknown - intent:
proposal,plan,order,original-order,reflex-order,filler-order,instance-order,option - medicationCodeableConcept: the medication (RxNorm codes preferred)
- dosageInstruction: how and when to take the medication
Next Steps
The next pages cover each medication resource in detail with end-to-end API examples.