weber pre-lecture pt 2 Flashcards
pages 22 - 43
what is an example of a factor Xa inhibitor (FXa)?
fondaparinux
what is the labeled used of fondaparinux?
prophylaxis following THA, TKA, hip placement, or abdominal surgery
treatment of DVT/PE
HIT
how is fondaparinux dosed?
based on weight for treatment
if prophylaxis, do not give for anyone under 50kg
do not use if have renal dysfunction
what is the monitoring of fonaparinux?
none for therapeutic efficacy
can monitor anti-Xa levels
what are example drugs of IV direct thrombin inhibitors?
lepirudin
bivalirudin (angiomax)
argatroban
what DTI has a different indication besides HIT?
bivalirudin (angiomax) is used as an UFH alternative during PCI
what DTI elevates INR?
argatroban
overlap with warfarin until INR is at least 4 to be weary against falsely high values
what DTI has adjusted dosing?
Lepirudin when CrCl is below 60mL/min
Argatroban when hepatic dysfunction is present
what are the brand names of warfarin?
coumadin
jantoven
what is the MOA of warfarin?
inhibits enzymes responsible for cyclic conversion of VIT K
inhibits synthesis of Vit K dependent clotting factors
what are the clotting factors associated with Vit K?
factors II, VII, IX, X
protein C and S
what enantiomer causes more drug-drug interactions in warfarin?
S enantiomer –> 5x more potent and interacts with CYP 2C9
when is the peak effect of warfarin seen?
72 to 96 hours
what is the duration of action from a single dose of warfarin?
2 to 5 days
when is anticoag effect seen with warfarin?
within 24 hours
what is the clearance of common clotting factors?
prothrombin –> 60 to 100hrs
VII –> 4 to 6 hrs
IX –> 20 to 30 hrs
X –> 24 to 40 hrs
what does it mean if a person has more *1 alleles?
more resistant to warfarin
what does it mean if a person has more 2/3 alleles?
more sensitive to warfarin (lower dose requirement)
what does it mean if a person has more A alleles?
more sensitive to warfarin
(lower dose requirement)
often seen in the asian population
what does it mean if a person has more G alleles?
more resistant to warfarin (higher dose requirement)
often seen in african americans
when should a person be genetically tested?
warfarin naive
results are available before the sixth dose
pt at a high risk of bleeding if INR is elevated
what drugs increase INR?
metronidazole
amiodarone
fluconazole
ciprofloxacin
bactrim
secondary –> erythromycin, anabolic steroids, isoniazid, liver disease, alcohol, and propafenone
what drugs decrease INR?
rifampin
secondary –> cholestyramine, carbamazepine, and alcohol
how does alcohol both increase and decrease INR?
acute ingestion –> increases INR
chronic ingestion without liver damage –> decreases INR
chronic ingestion with liver damage –> increased anticoag effect
