RxClass API

The RxClass API is a web service for accessing drug classes and drug members for a number of different drug class types. See RxClass Overview.

Use of the API is subject to Terms of Service. No license is needed to use the RxClass API.

Upcoming Changes On or After July 5, 2021:
  • "relaSource" will be returned consistently, all-uppercase.

  • API calls that cannot be processed, because of invalid parameters, will result in HTTP error code 400 ("Bad Request").

For details, see API Changes - On or After July 5, 2021.


FunctionREST ResourceDescription
findClassByName/class/byNameDrug classes with a specified class name
findClassesById/class/byIdDrug classes with a specified class identifier
findSimilarClassesByClass/class/similarClasses with similar clinically-significant RxNorm ingredients
findSimilarClassesByDrugList/class/similarByRxcuisClasses with clinically-significant RxNorm ingredients similar to a specified list
getAllClasses/allClassesAll classes (may limit by class type)
getClassByRxNormDrugId/class/byRxcuiClasses containing a specified drug RXCUI
getClassByRxNormDrugName/class/byDrugNameClasses containing a drug of the specified name
getClassContexts/classContextPaths from the specified class to the root of its class hierarchies
getClassGraphBySource/classGraphClasses along the path from a specified class to the root of a class hierarchy
getClassMembers/classMembersDrug members of a specified class
getClassTree/classTreeSubclasses or descendants of the specified class
getClassTypes/classTypesClass types
getRelas/relasRelationships expressed by a source of drug relations
getSimilarityInformation/class/similarInfoSimilarity of the clinically-significant membership of two classes
getSourcesOfDrugClassRelations/relaSourcesSources of drug-class relations
getSpellingSuggestions/spellingsuggestionsDrug or class names similar to a given string