diff --git a/src/bdchm/schema/bdchm.yaml b/src/bdchm/schema/bdchm.yaml
index 9e1aae2..642e0c1 100644
--- a/src/bdchm/schema/bdchm.yaml
+++ b/src/bdchm/schema/bdchm.yaml
@@ -1778,7 +1778,8 @@ enums:
         description: The condition is/was of unknown status in the patient.
 
   DrugExposureConceptEnum:
-    description: A constrained set of enumerative values containing RxNorm concepts.
+    description: Drug codes from RxNorm.
+    comment: Not sure best way to access, but found the following at HL7.
     see_also:
       - https://terminology.hl7.org/3.1.0/CodeSystem-v3-rxNorm.html
       - http://www.nlm.nih.gov/research/umls/rxnorm