hematologic agents Flashcards
what is the role of heparin sulfate on vascular endothelial cells?
binds to ATIII–>significantly incr rate of thrombin & factor Xa inactivation
where is fibrinogen converted to fibrin?
the active site of thrombin (E1 site)
does the antithrombin/heparin complex inhibit thrombin when bound or only when unbound?
does NOT inhibit thrombin bound to fibrin, only binds when thrombin is not bound to fibrin
role of antithrombin/heparin complex
prevents thrombin from being inactivated at site of clot
what type of thrombosis is a platelet poor clot?
venous thrombosis
DVT–>VTE–>PE
are antiplatelet tx used for tx of DVT?
no. heparin usually administered
which type of thrombosis is platelet rich?
arterial thrombosis
antiplatelet tx useful for tx
where do arterial thrombosis normally occur?
on top of ruptured atherosclerotic plaques
what is teh most common cause of MI and ischemic strokes?
arterial thrombosis
common causes of thrombosis
cancer, A fib, placement of mechanical heart valves, lower limb orthopedic surgery, prolonged bed rest, OCP, factor V leiden
what are used in primary prevention of MI or stroke?
antiplatelet drugs
What is DAPT?
dual antiplatelet tx—>use to prevent MI, sudden cardiac death:
combo of ASA + P2Y12 antagonist
main applications of anticoagulants
tx & prevent venous thrombosis/venous thromboembolism
- A fib
- major surgeries
- cancer
- DVT, pulmonary thromboembolism
where is heparin normally found?
found in mast cells in the body, NOT in plasma
does half life of heparin change as dose increases?
yes, half life increases as dose increases
what is the antidote if too much heparin is administered?
protamine sulfate binds to and inactivates heparin molec
which type of HIT is fatal?
type 2
what happens in HIT II?
- heparin binds PF4
- antibodies generated towards PF4/heparin complex
- antibodies bind platelets
- platelets cleared by macrophages
- venous & arterial thrombosis
what is the anti-factor Xa assay used for?
directly measures activity of factor Xa
monitor LMWH + fondaparinux
which drugs can be used to stop clotting at the site of the clot?
bicalrudin, lepirudin, argtroban, dibigatran
wht is the target INR that you want to see after giving someone warfarin?
2-3
drugs that potentiate warfarin’s effect do what to INR?
increase INR
drugs that inhibit warfarin do what to INR?
decr INR
if have renal insufficiency, & on warfarin, what will happen to INR?
- renal insufficiency–>hypoalbuminemia
- less albumin for warfarin to be bound to–>more warfarin in active form
- INR incr
