Term
| Which isomer of warfarin is more powerful and how is it metabolized? |
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Definition
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Term
| What CYP2C9 alleles are wild type and which are impaired? |
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Definition
- CYP2C9*1 - wild type
-CYP2C9*2/*3 - decreased metabolic activity, usually in caucasians
-CYP2C9*5 - decreased metabolic activity only in african americans
- The more impaired, the lower the necessary dose |
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Term
| How do VKORC1 2C9 variant alleles affect dose requirements? |
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Definition
| Any variant allele has decreased dose requirements. 2 alleles drastically reduces dosing requirements |
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Term
| What are the effects of having a CYP2C9 *2 or *3 allele? |
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Definition
- increased risk of higher INR
- Longer time to stabilize dosing
- Higher risk of bleeding |
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Term
| In the VKORC1 haplotype, what do A and B represent? |
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Definition
- Type A - low dosing. Asians
- Type B - high dosing. Europeans
- Heterozygous - normal dosing |
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Term
| How do VKORC1 haplotypes and 2C9 variant alleles combine to affect warfarin dosing? |
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Definition
If a variant allele is present, and the A haplotype is present (AA or AB), dosing is drastically reduced.
If 2C9 is wild-type, and B haplotype is present, then dosing is increased |
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