Fluconazole and Warfarin: Drug Interaction Guide
Quick answer: This is a major interaction — avoid combining Fluconazole and Warfarin unless specifically directed by your doctor.
How Fluconazole interacts with Warfarin
Fluconazole inhibits CYP2C9 and CYP3A4, the principal enzymes metabolizing warfarin, substantially increasing INR and bleeding risk.
What you should do
Reduce warfarin dose by approximately 25-50% at fluconazole initiation and check INR within 3-5 days, then weekly until stable.
Key facts
Severity
Major — avoid combination
Mechanism
Fluconazole inhibits CYP2C9 and CYP3A4, the principal enzymes metabolizing warfarin, substantially increasing INR and bl...
Action
Reduce warfarin dose by approximately 25-50% at fluconazole initiation and check INR within 3-5 days, then weekly until ...
Frequently asked questions
Can I take Fluconazole and Warfarin together?
No — this combination should generally be avoided. Reduce warfarin dose by approximately 25-50% at fluconazole initiation and check INR within 3-5 days, then weekly until stable.
What is the severity of this interaction?
The interaction between Fluconazole and Warfarin is classified as Major — avoid combination. Fluconazole inhibits CYP2C9 and CYP3A4, the principal enzymes metabolizing warfarin, substantially increasing INR and bleeding risk.
What should I do if I'm prescribed both?
Reduce warfarin dose by approximately 25-50% at fluconazole initiation and check INR within 3-5 days, then weekly 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.