Thromb Haemost 2003; 89(05): 842-846
DOI: 10.1055/s-0037-1613471
Blood Coagulation, Fibrinolysis and Cellular Haemostasis
Schattauer GmbH

Clopidogrel and warfarin: absence of interaction in patients receiving long-term anticoagulant therapy for non-valvular atrial fibrillation

Christer Lidell
1   Department of Cardiology, Uppsala University Hospital, Sweden
,
Lars-Erik Svedberg
2   Department of Medicine, Bollnäs Hospital, Sweden
,
Peter Lindell
3   Department of Cardiology, Huddinge Hospital, Sweden
,
Stellan Bandh
4   Department of Cardiology, Västeras Hospital, Sweden
,
Bernhard Job
5   Sanofi-Synthélabo Recherche, Chilly-Mazarin, France
,
Lars Wallentin
1   Department of Cardiology, Uppsala University Hospital, Sweden
› Institutsangaben
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Publikationsverlauf

Received 05. September 2002

Accepted after revision 04. Februar 2003

Publikationsdatum:
09. Dezember 2017 (online)

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Summary

The effect of concomitantly administered clopidogrel on anticoagulation status was investigated in patients receiving long-term warfarin therapy. Forty-three patients with non-valvular atrial fibrillation who were receiving long-term warfarin and had a stable international normalized ratio (INR) between 2 and 3 were randomly assigned to clopidogrel 75 mg daily or placebo for 8 days (Days 1–8). INR (primary endpoint) and plasma levels of warfarin enantiomers (secondary endpoint) were evaluated at Days 3, 6, 9, 13 and 22. Mean INR remained extremely stable in the clopidogrel group, the maximum percentage change from baseline being 0.6% at Day 6. Plasma levels of R- and S-warfarin also remained very stable in those receiving clopidogrel. No serious adverse events, premature discontinuations of study drug or bleeding occurred with clopidogrel. In conclusion, the stable anticoagulation status of patients receiving long-term warfarin therapy is unaffected by concomitant administration of clopidogrel 75 mg daily.