<StructureDefinition xmlns="http://hl7.org/fhir">
  <url value="https://example.org/fhir/StructureDefinition/MyMedication" />
  <name value="MyMedication" />
  <status value="draft" />
  <fhirVersion value="4.0.1" />
  <kind value="resource" />
  <abstract value="false" />
  <type value="Medication" />
  <baseDefinition value="http://hl7.org/fhir/StructureDefinition/Medication" />
  <derivation value="constraint" />
  <differential>
    <element id="Medication.identifier">
      <path value="Medication.identifier" />
      <label value="anti_arrhythmic_id, beta_blocker_id" />
    </element>
    <element id="Medication.code">
      <path value="Medication.code" />
      <label value="anti_arrhythmic_name, beta_blocker_name" />
    </element>
  </differential>
</StructureDefinition>