Table 2.
Estimated warfarin dose (mg/day) at stable INR, stratified by CYP2C9 genotype and VKORC1 haplotype, derived from a warfarin dosing algorithm.65
| CYP2C9 genotype | ||||||
|---|---|---|---|---|---|---|
| Rapid Metabolism |
Intermediate Metabolism |
Poor Metabolism |
||||
| VKORC | *1/ *1 | *1/ *2 | *1/ *3 | *2/ *2 | *2/ *3 | *3/ *3 |
| haplotype | ||||||
| High (BB) | 6.7 | 5.4 | 4.5 | 4.4 | 3.6 | 3.0 |
| Medium (AB) | 4.8 | 3.9 | 3.2 | 3.2 | 2.6 | 2.2 |
| Low (AA) | 3.5 | 2.8 | 2.3 | 2.3 | 1.9 | 1.6 |
Where age=65 years, BSA 1.96 m2 (weight = 180 lbs, height=5’8”), non-smoker, target INR of 2.75 and no other drugs VKORC1 haplotype- BB indicates wild-type, AB indicates heterozygote and AA indicates homozygote for variant allele