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Amoxicillin/clavulanic acid-warfarin drug interaction: a randomized controlled trial
Qian Zhang1, Guy Simoneau, Celine Verstuyft
1University of Paris VII-Denis Diderot, Therapeutic Research Unit, Department of Internal Medicine, Lariboisière Hospital, Paris, France.
Amoxicillin/clavulanic acid (amoxiclav) does not affect warfarin anticoagulation in patients on stable therapy. This study found no significant interaction between amoxiclav and warfarin, ensuring safe co-administration.
Area of Science:
- Pharmacology
- Clinical Pharmacy
Background:
- Warfarin is a commonly prescribed oral anticoagulant.
- Amoxicillin/clavulanic acid is a frequently used antibiotic.
- Potential drug interactions between antibiotics and anticoagulants require investigation.
Purpose of the Study:
- To determine if amoxicillin/clavulanic acid (amoxiclav) interacts with warfarin.
- To assess the impact of amoxiclav on anticoagulation status in patients on stable warfarin therapy.
Main Methods:
- A double-blind, cross-over, placebo-controlled study was conducted.
- Twelve patients on stable warfarin therapy participated.
- Participants received a 7-day regimen of either amoxiclav or placebo.
Main Results:
- The mean maximum increase in INR was minimal and not significantly different between amoxiclav (0.22 ± 0.3) and placebo (0.24 ± 0.6) groups (P=0.94).
- Warfarin plasma concentrations (factor II, R(-) and S(-) enantiomers) remained similar during both treatment periods (P > 0.45 for all).
Conclusions:
- Amoxiclav does not alter anticoagulation levels in patients receiving stable warfarin therapy.
- The findings suggest amoxiclav can be safely co-administered with warfarin in non-infected patients.
- No clinically significant drug interaction was observed between amoxiclav and warfarin.
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