Send to

Choose Destination
See comment in PubMed Commons below
Eur J Clin Pharmacol. 2009 Apr;65(4):365-75. doi: 10.1007/s00228-008-0584-5. Epub 2008 Nov 25.

Influence of CYP2C9 genotype on warfarin dose requirements--a systematic review and meta-analysis.

Author information

  • 1Division of Clinical Pharmacology, Karolinska Institutet, Stockholm, Sweden.



To quantify the influence of common cytochrome P450 2C9 (CYP2C9) polymorphisms on warfarin dose requirements.


A systematic review and a meta-analysis, calculating the warfarin dose reduction associated with the five most common variant CYP2C9 genotypes.


Thirty-nine studies (7,907 patients) were included in the meta-analysis. Compared to the CYP2C9*1/*1 genotype, the CYP2C9*1/*2, CYP2C9*1/*3, CYP2C9*2/*2, CYP2C9*2/*3, and CYP2C9*3/*3 required warfarin doses that were 19.6 (95% confidence interval 17.4, 21.9), 33.7 (29.4, 38.1), 36.0 (29.9, 42.0), 56.7 (49.1, 64.3), and 78.1% (72.0, 84.3) lower, respectively. The impact of CYP2C9 genotype tended to be larger in patients without interacting drugs.


Previous studies have rarely been powered to determine the quantitative influence of specific CYP2C9 genotypes on warfarin dose requirements. The results from our pooled analysis are likely to be the most accurate to date and the methodology could serve as a model for future pharmacogenetic meta-analyses.

[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Springer
    Loading ...
    Write to the Help Desk