anticoagulants Flashcards
unfractionated heparin MOA
binds to antithrombin III
inhibition of factor II and X
small platelet inhibition
unfractionated heparin/LMWH antidote
protamine
heparin monitoring and normal ranges
PTT - 50-80 sec (1.5-3x baseline is therapeutic)
anti Xa - 0.3-0.7 U/mL
adverse effects of heparin
bleeding
skin necrosis, HIT, altered bone metabolism
HIT diagnosis
antibody tests
4 T’s score
HIT treatment
argatroban
also fondaparinux and bivalrudin but not FDA approved
LMWH MOA
binds w antithrombin to inhibit factor X
mild inhibition of factor II
UFH vs LMWH
LMWH has more predictable response, less bleeding, no routine lab monitoring, able to be given as outpatient
dosing adjustment for LMWH
renal
bivalrudin MOA
direct thrombin inhibitor
dosing adjustment for bivalrudin
renal
bivalrudin dosing
0.1 mg/kg bolus, then 0.25 mg/kg/h
argatroban MOA
direct thrombin inhibitor
bivalrudin/argatroban monitoring
PTT
argatroban dosing
1.7-2.0 mcg/kg/min
good anticoagulant & DOAC for renal impairment
argatroban
apixaban
argatroban dosing adjustment
liver dysfunction
fondaparinux MOA
long acting factor X inhibitor
fondaparinux contraindication
CrCl<30
warfarin MOA
inhibits production of vitamin K dependent clotting factors II, VII, IX and X
converts inactive vitamin K to active vitamin K
inhibits protein C and S
warfarin half life
60 hours
max impact is 5-7 days
may need to bridge w lovenox
warfarin dosing
5-7.5 mg daily, then titrate to INR (2-3) q 5-7 days
warfarin AEs
bleeding (higher w fluconazole, amio, bactrim, metronizadole)
skin necrosis, purple toe syndrome, vasculitis
warfarin & factor x inhibitors antidote
vitamin K, kcentra
DOACs vs warfarin
DOACs more predictable, more rapid onset/offset, no routine monitoring, less risk of ICH and fatal hemorrhage
DOAC more expensive
warfarin indicated for mechanical valves
dabigatran MOA
direct thrombin inhibitor
rivaroxaban, apixaban, edoxaban MOA
factor Xa inhibitor
periop considerations for dabigatran
may need to hold dose for up to 5 days before surgery depending on CrCl
how long to hold factor X inhibitors before surgery
low risk procedures -24 h
high risk procedures - 48 h
dabigatran antidote
idarucizumab
anti xa inhibitors antidote
andexxa
