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Medication Category and Dosage Form in a Prescription

The MedicationRequest.category Field​

The MedicationRequest.category field, defined as an array of the FHIR CodeableConcept datatype, serves to classify the medication request. This classification provides crucial context regarding where the medication is intended for consumption or administration, as well as the general type of medication treatment. We utilize this field to store both a high-level classification of the MedicationRequest as mandated by FHIR and potentially more specific medication categories.

High-Level Classification Based on Context​

FHIR defines a set of example codes for the category field, providing a standardized way to classify medication requests based on their intended context of use. This high-level classification is essential for various healthcare workflows, filtering, and reporting. The MedicationRequest Category Codes value set suggests the following general categories:

CodeDisplayDefinition
inpatientInpatientIncludes requests for medications to be administered or consumed in an inpatient or acute care setting.
outpatientOutpatientIncludes requests for medications to be administered or consumed in an outpatient setting (for example, Emergency Department, Outpatient Clinic, Outpatient Surgery, Doctor's office).
communityCommunityIncludes requests for medications to be administered or consumed by the patient in their home (this would include long term care or nursing homes, hospices, etc.).
dischargeDischargeIncludes requests for medications created when the patient is being released from a facility.
Our Application's Usage

Currently, our application primarily deals with medication requests within the inpatient setting. Therefore, we consistently include the inpatient code as the default high-level classification for all MedicationRequest resources we create.

Example: Inpatient MedicationRequest Category
{
    "category": [
{
    "coding": [
{
    "system": "[http://terminology.hl7.org/CodeSystem/medicationrequest-category](http://terminology.hl7.org/CodeSystem/medicationrequest-category)",
    "code": "inpatient",
    "display": "Inpatient"
}
    ],
    "text": "Inpatient"
}
    ]
}

This example demonstrates a MedicationRequest where the category field contains a CodeableConcept. The coding array specifies the standard FHIR code for inpatient medication requests, using the official HL7 code system. The text field provides a human-readable representation of this code.

Limitation

The high-level classification of MedicationRequest in our current application is assumed to be inpatient. This means that all prescriptions created within the system are automatically categorized with the inpatient code, as detailed in the High-Level Classification Table. This assumption is based on the current scope and functionality of our application.

To extend the capabilities of our system and align more closely with the full flexibility offered by the FHIR standard, we recognize the need to provide users with the option to select the relevant classification category for each MedicationRequest. This would involve implementing a user interface element that allows users to choose from the categories listed in the MedicationRequest Category Codes value set (e.g., inpatient, outpatient, community, discharge).

Medication Category​

The category field in the MedicationRequest resource was previously utilized to facilitate the grouping of prescriptions by Medication's intended mode of administration or physical form within the user interface (e.g., Tablets, SYRINGE_PUMPS, INJECTIONS, INFUSIONS, BLOOD_PRODUCTS, ENTERAL_NUTRITION). This allowed for a more organized presentation of medication prescriptions based on medication categories. Also, a secondary purpose was to attach various field logic to it, i.e., if the Medication Category was a Tablet kind, then only the amount and volume fields were prompted to the User. With the Medication API, this secondary purpose becomes obsolete.

However, to align more closely with the FHIR standard and maintain a semantically accurate data model, we have decided to discontinue the use of the category field for this UI grouping logic.

Moving forward, the UI grouping of medication requests based on administration will be primarily driven by the information present in the MedicationRequest.dosageInstruction.route (the path by which the medication is taken into or onto the body, e.g., oral, intravenous) and MedicationRequest.dosageInstruction.method (the means by which the medication is taken into or onto the body, e.g., swallow, infusion pump) fields.

Dosage Form​

The form field within the FHIR Medication resource is a CodeableConcept that serves to describe the physical form of the medication product. This field indicates in which form the Medication shall be given to the Patient. It helps to identify and differentiate between various presentations of the same medication. For example, Amoxicillin can come in tablet, capsule, or suspension form. The form field clarifies which specific presentation the Medication resource refers to.

FHIR provides a comprehensive FHIR Medication Form Codes ValueSet that suggests codes from standardized terminologies like SNOMED CT for representing medication forms. Utilizing these codes is recommended for better interoperability.

Example: Medication with Dosage Form

{
    "form": {
        "coding": [
            {
                "system": "http://snomed.info/sct",
                "code": "385219001",
                "display": "Injection solution (qualifier vallue)"
            }
        ]
    }
}
Mona 2

Currently, in Mona 2, the Dosage Form is stored as part of the MedicationRequest resource's medicationCodeableConcept field. As outlined above, this information will be migrated to the form field within the referenced Medication resource to align with the FHIR standard.