Warfarin and Focus on the Ambulatory Setting Flashcards
(27 cards)
CPIC
Clinical Pharmacogenomics Implementation Consortium
DES
drug eluding stent
INR
international normalized ratio
ISI
international sensitivity index
LAD
left anterior descending artery
PT
prothrombin time
VTE
venous thromboembolism
VKA
vitamin k antagonist
VKOR
vitamin k epoxide reductase
How does warfarin work?
Warfarin blocks the production of the vitamin k dependent clotting factors II, VII, IX, and X. It does this by binding to the vitamin K epoxide reductase, which stops the reduction of oxidized vitamin k preventing its recycling of making more activated clotting factors.
Warfarin does nothing to affect clotting factors already in the system causing delayed onset.
Clotting factor half-life’s
Draw diagram for vitamin k dependent clotting factors synthesis
Draw the table listing the different pharmacokinetics with (R) and (S) Warfarin.
What are the four most common drugs that inhibits 2C9
Amioderone
Sulfamethoxazole
Metronidazole
Fluconazole
What is ISI and what value is recommended
The international sensitivity index is used to standardize INR tests between labs. The closer to 1, the more responsive. It’s recommended to use agents with ISI < 1.4
What is the equation to calculate an INR?
Warfarin therapeutic range
Always identify type of heart valve used
18 factors that affect warfarin dosing needs
What genetic factors are most likely to affect warfarin dosing?
CYP2C9 influences the clearing of warfarin
VKOR encoded by VKORC1 gene affects warfarin response
CYP4F2 is a liver vitamin k oxidase that removes vitamin k from the vitamin k cycle
Asians tend to need lower doses and African Americans tend to need higher doses
The CPIC has helpful guidelines
Average daily dosing method
Flexible initiation method
Frequency of Monitoring for initiation of therapy
Flexible initiation method
