Voriconazole and Warfarin: Drug Interaction Guide
Quick answer: This is a major interaction — avoid combining Voriconazole and Warfarin unless specifically directed by your doctor.
How Voriconazole interacts with Warfarin
Voriconazole strongly inhibits CYP2C9 and CYP3A4, raising S-warfarin levels and prolonging prothrombin time with significant bleeding risk.
What you should do
Reduce warfarin dose empirically by 25-50% when starting voriconazole and monitor INR every 2-3 days until stable.
Key facts
Severity
Major — avoid combination
Mechanism
Voriconazole strongly inhibits CYP2C9 and CYP3A4, raising S-warfarin levels and prolonging prothrombin time with signifi...
Action
Reduce warfarin dose empirically by 25-50% when starting voriconazole and monitor INR every 2-3 days until stable.
Frequently asked questions
Can I take Voriconazole and Warfarin together?
No — this combination should generally be avoided. Reduce warfarin dose empirically by 25-50% when starting voriconazole and monitor INR every 2-3 days until stable.
What is the severity of this interaction?
The interaction between Voriconazole and Warfarin is classified as Major — avoid combination. Voriconazole strongly inhibits CYP2C9 and CYP3A4, raising S-warfarin levels and prolonging prothrombin time with significant bleeding risk.
What should I do if I'm prescribed both?
Reduce warfarin dose empirically by 25-50% when starting voriconazole and monitor INR every 2-3 days until stable. Always consult your prescribing clinician — do not stop or change medications without medical guidance.
Last reviewed: by iMedic Medical Editorial Team. Our editorial process.