Long-term anticoagulant effects of the CYP2C9 and VKORC1 genotypes in acenocoumarol users
Article first published online: 30 MAR 2012
© 2012 International Society on Thrombosis and Haemostasis
Journal of Thrombosis and Haemostasis
Volume 10, Issue 4, pages 606–614, April 2012
How to Cite
VERHOEF, T. I., REDEKOP, W. K., BUIKEMA, M. M., SCHALEKAMP, T., VAN DER MEER, F. J. M., LE CESSIE, S., WESSELS, J. A. M., VAN SCHIE, R. M. F., DE BOER, A., TEICHERT, M., VISSER, L. E., MAITLAND-VAN DER ZEE, A. H. and ON BEHALF OF THE EU-PACT GROUP (2012), Long-term anticoagulant effects of the CYP2C9 and VKORC1 genotypes in acenocoumarol users. Journal of Thrombosis and Haemostasis, 10: 606–614. doi: 10.1111/j.1538-7836.2012.04633.x
- Issue published online: 30 MAR 2012
- Article first published online: 30 MAR 2012
- Accepted manuscript online: 17 JAN 2012 07:30PM EST
- Received 8 November 2011, accepted 24 December 2011
- cytochrome P450 2C9;
- International Normalized Ratio;
- Vitamin K epoxide reductase multiprotein complex 1
Summary. Background: The required acenocoumarol dose and the risk of underanticoagulation and overanticoagulation are associated with the CYP2C9 and VKORC1 genotypes. However, the duration of the effects of these genes on anticoagulation is not yet known.
Objectives: In the present study, the effects of these polymorphisms on the risk of underanticoagulation and overanticoagulation over time after the start of acenocoumarol were investigated.
Patients/methods: In three cohorts, we analyzed the relationship between the CYP2C9 and VKORC1 genotypes and the incidence of subtherapeutic or supratherapeutic International Normalized Ratio (INR) values (< 2 and > 3.5) or severe overanticoagulation (INR > 6) for different time periods after treatment initiation.
Results: Patients with polymorphisms in CYP2C9 and VKORC1 had a higher risk of overanticoagulation (up to 74%) and a lower risk of underanticoagulation (down to 45%) in the first month of treatment with acenocoumarol, but this effect diminished after 1–6 months.
Conclusions: Knowledge of the patient’s genotype therefore might assist physicians to adjust doses in the first month(s) of therapy.