Does Mercaptopurine Interact with Warfarin?
Mercaptopurine and Warfarin have a moderate drug interaction according to U.S. FDA drug labeling data. Mercaptopurine may decrease anticoagulant effectiveness of warfarin. Monitor INR and adjust warfarin dosage as appropriate. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.
- Severity
- Moderate
- Management
- Monitor for effects
- Data Source
- U.S. FDA via OpenFDA
What To Tell Your Doctor or Pharmacist
If you are taking Mercaptopurine and your doctor is considering prescribing Warfarin (or vice versa), make sure to:
- Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
- Ask whether the benefits of combining these medications outweigh the risks for your specific situation
- Ask what symptoms to watch for that would indicate the interaction is causing problems
- Ask whether any dosage adjustments are needed
- Never stop or change either medication without first consulting your healthcare provider