Quinolone and Warfarin: Drug Interaction Guide
Quick answer: This combination requires caution. Quinolone and Warfarin can be used together with adjustments and monitoring.
How Quinolone interacts with Warfarin
Ciprofloxacin and other fluoroquinolones inhibit CYP1A2 and CYP3A4, and may alter gut flora that produce vitamin K, increasing warfarin effect and INR.
What you should do
Check INR within 3–5 days of starting a fluoroquinolone and adjust warfarin dose as needed. Counsel patient on bleeding signs.
Key facts
Severity
Moderate — caution required
Mechanism
Ciprofloxacin and other fluoroquinolones inhibit CYP1A2 and CYP3A4, and may alter gut flora that produce vitamin K, incr...
Action
Check INR within 3–5 days of starting a fluoroquinolone and adjust warfarin dose as needed. Counsel patient on bleeding ...
Frequently asked questions
Can I take Quinolone and Warfarin together?
With caution. Check INR within 3–5 days of starting a fluoroquinolone and adjust warfarin dose as needed. Counsel patient on bleeding signs.
What is the severity of this interaction?
The interaction between Quinolone and Warfarin is classified as Moderate — caution required. Ciprofloxacin and other fluoroquinolones inhibit CYP1A2 and CYP3A4, and may alter gut flora that produce vitamin K, increasing warfarin effect and INR.
What should I do if I'm prescribed both?
Check INR within 3–5 days of starting a fluoroquinolone and adjust warfarin dose as needed. Counsel patient on bleeding signs. Always consult your prescribing clinician — do not stop or change medications without medical guidance.
Last reviewed: by iMedic Medical Editorial Team. Our editorial process.