This code system http://hl7.org/fhir/interaction-type defines the following codes:

Code Display
drug-drug drug to drug interaction
drug-food drug to food interaction
drug-test drug to laboratory test interaction
other other interaction
<status value="active"/> <experimental value="false"/> <date value="2021-01-05T10:01:24+11:00"/> <publisher value="HL7 (FHIR Project)"/> <contact> <telecom> <system value="url"/> <value value="http://hl7.org/fhir"/> </telecom> <telecom> <system value="email"/> <value value="fhir@lists.hl7.org"/> </telecom> </contact> <description value="A categorisation for an interaction between two substances."/> <jurisdiction> <coding> <system value="http://unstats.un.org/unsd/methods/m49/m49.htm"/> <code value="001"/> <display value="World"/> </coding> </jurisdiction> <caseSensitive value="true"/> <valueSet value="http://hl7.org/fhir/ValueSet/interaction-type"/> <content value="complete"/> <concept> <code value="drug-drug"/> <display value="drug to drug interaction"/> </concept> <concept> <code value="drug-food"/> <display value="drug to food interaction"/> </concept> <concept> <code value="drug-test"/> <display value="drug to laboratory test interaction"/> </concept> <concept> <code value="other"/> <display value="other interaction"/> </concept> </CodeSystem>