Thiopurine and Warfarin: Drug Interaction Guide
Quick answer: This combination requires caution. Thiopurine and Warfarin can be used together with adjustments and monitoring.
How Thiopurine interacts with Warfarin
Azathioprine and mercaptopurine reduce the anticoagulant effect of warfarin through an unclear mechanism, possibly involving increased synthesis of clotting factors or enzyme induction.
What you should do
Monitor INR weekly when starting or stopping thiopurine therapy and anticipate increased warfarin dose requirements.
Key facts
Severity
Moderate — caution required
Mechanism
Azathioprine and mercaptopurine reduce the anticoagulant effect of warfarin through an unclear mechanism, possibly invol...
Action
Monitor INR weekly when starting or stopping thiopurine therapy and anticipate increased warfarin dose requirements.
Frequently asked questions
Can I take Thiopurine and Warfarin together?
With caution. Monitor INR weekly when starting or stopping thiopurine therapy and anticipate increased warfarin dose requirements.
What is the severity of this interaction?
The interaction between Thiopurine and Warfarin is classified as Moderate — caution required. Azathioprine and mercaptopurine reduce the anticoagulant effect of warfarin through an unclear mechanism, possibly involving increased synthesis of clotting factors or enzyme induction.
What should I do if I'm prescribed both?
Monitor INR weekly when starting or stopping thiopurine therapy and anticipate increased warfarin dose requirements. Always consult your prescribing clinician — do not stop or change medications without medical guidance.
Last reviewed: by iMedic Medical Editorial Team. Our editorial process.