24 - Antithrombotic Therapy Flashcards
what factors does unfractionated heparin inhibit?
Xa and IIa
what factor do low MW heparin and fondaparinux inhibit?
Xa
what can be given to “undo” heparin?
protamine
does LMW heparin need monitoring?
no - only unfractionated does
side effects of heparin
bleeding
osteopenia / bone loss
heparin induced thrombocytopenia (HIT)
mechanism for HIT
heparin binds platelet factor 4 > IgG produced against this complex > aggregation and removal from ciruclation
fondaparinux
synthetic heparin like molecule that only inhibits F.Xa and has less side effects
key to tx of HIT
stop ALL heparin (even catheters and stuff coated with it) and treat w/ alternative anti coag and avoid platelet transfusions
warfarin mechanism
inhibits enzymes that regenerate reduced form of Vit K
why does warfarin need to be monitored so closely?
levels can change significantly due to lots of food/drug interactions
antidotes for warfarin
vit K, FFP
unique side effects of warfarin
embryopathy (6-12 wks GA), warfarin induced skin necrosis
mechanism for warfarin induced skin necrosis
since warfarin first inactivates protein C, get paradoxical pro-coagulation stage early on which causes small clots in skin vessels > necrosis. can be avoided by “bridging” them past this period on another anti coag
lepirudin, bivalirudin, argatroban are ___ and are primarily used for ___
IV direct thrombin inhibitors
HIT
oral direct thrombin inhibitor
dabigatran
