Drug interactions
amoxicillin/clavulanate + warfarin
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Overview
Broad-spectrum antibiotic may potentiate warfarin, increasing INR and bleeding risk during and shortly after therapy.
Mechanism of action
Reduction of vitamin K–producing gut flora → enhanced anticoagulant effect of warfarin; illness/poor intake may contribute.
Clinical management
Check INR prior to or soon after starting; recheck within 3–5 days and after completion; adjust warfarin per INR; counsel on bleeding; consider alternative if history of unstable INRs.
Drug reference
References
- Warfarin: Drug information — Lexicomp
- Coumadin (warfarin sodium) Prescribing Information — FDA Label
- Amoxicillin/clavulanate and warfarin Interactions — Drugs.com
Frequently asked questions
Can I take amoxicillin/clavulanate with warfarin?
The interaction is rated: Moderate. Broad-spectrum antibiotic may potentiate warfarin, increasing INR and bleeding risk during and shortly after therapy.
How serious is the interaction between amoxicillin/clavulanate and warfarin?
The interaction is rated: Moderate. Evidence level: Moderate.
How is the interaction between amoxicillin/clavulanate and warfarin managed?
Check INR prior to or soon after starting; recheck within 3–5 days and after completion; adjust warfarin per INR; counsel on bleeding; consider alternative if history of unstable INRs.
Why do amoxicillin/clavulanate and warfarin interact?
Reduction of vitamin K–producing gut flora → enhanced anticoagulant effect of warfarin; illness/poor intake may contribute.
Full monographs, dosing and an interaction checker in the MediHelp app
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