final lecture 5 Flashcards
anticoagulant effect of UFH is mediated through
pentasaccharide sequence
minimum length of UFH saccharide chain required to bind to thrombin:
18 units
UFH has high protein binding to
PF4
UFH antidote
protamine sulfate
two types of thrombocytopenia
heparin-associated (HAT) &heparin-induced (HIT)
HAT
mild; reversible
HIT
a serious drug rxn
main difference between LMWH & UFH
their relative ability to inhibit Xa and thrombin
LMWH action
limited anti-thrombin activity but greater anti-factor Xa
LMWH advantages over UFH
more predictable dose response, dose-independent clearance (renal), longer T1/2. lower risk of HIT or osteoporosis, reduced lab monitoring
LMWH antidote
protamine sulfate
fondaparinux has ___ effect on thrombin activity
no direct effect
fondoparinux antidote
none
fondaparinux CI in
pts <50kg
anti Xa
fondparinux and idraparinux
DIRECT anti-factor Xa inhibitors
rivaroxaban & apixban ORAL do not require antithrombin no antidotes CYP interaction
DTIs over UFH, LMWH
do not require cofactor (antithrombin), inhibit BOTH circulating and clot bound thrombin, treatment of HIT
DTIs are derived from
hirudin salivary gland of a leach
lepirudin
DTI
parenteral
binds irreversibly to thrombin
renal excretion
desirudin
DTI
a little long T`1/2
irreversibly binds
renal excretion
bivalirudin
DTI
reversibly binds- lower risk of bleeding
short T1/2
hepative metabolism
argatroban
DTI
IV
binds reversibly only to active site of thrombin
metabolized in liver- can use in renal impairment
dabigatran
DTI
PO
renal clearance
used for DVT prophylaxis for orthopedic surgery
