Drug Interaction API
The Interaction API is a web service for accessing drug-drug interactions. No license is needed to use the Interaction API.

Currently, the API uses two sources for its interaction information - ONCHigh and DrugBank. ONCHigh is a list of high-priority drug-drug interactions derived by a panel of experts and contained in a JAMIA article . DrugBank contains the drug-drug interactions contained in the DrugBank database.
Severity levels: DrugBank contains no severity levels for its iteractions. ONCHigh interactions are all high-priority severity.

The drug-drug interactions are updated monthly, usually on the first Monday of the month.

DrugBank Disclaimer: DrugBank is intended for educational and scientific research purposes only and you expressly acknowledge and agree that use of DrugBank is at your sole risk. The accuracy of DrugBank information is not guaranteed and reliance on DrugBank shall be at your sole risk. DrugBank is not intended as a substitute for professional medical advice, diagnosis or treatment.
Citing DrugBank:
Wishart DS, Knox C, Guo AC, Shrivastava S, Hassanali M, Stothard P, Chang Z, Woolsey J. DrugBank: a comprehensive resource for in silico drug discovery and exploration. Nucleic Acids Res. 2006 Jan 1;34(Database issue):D668-72. 16381955

The API can be accessed by clients in two different ways:
Note: Please check the Terms of Service for restrictions on using the APIs.

Functions and Resources

In the table, the base URI ( https://rxnav.nlm.nih.gov/REST/interaction ) for the REST resources has been omitted to improve readability.

SOAP Function REST Resource Description
findDrugInteractions /interaction Find the interactions of an RxNorm drug (specified by RxCUI)
findInteractionsFromList /list Find the interactions between a list of drugs
getInteractionSources /sources newGet the sources of the interactions
getVersion /version Get the version of the data set(s)