Which drug interferes with the final step of platelet aggregation?
This is a IIb/IIIa receptor blocker which is the final step of platelet aggregation where fibrin cross linking occurs
T/F: inhibitors of platelet aggregation can decrease risk of stroke, MI and colo-rectal cancer
Si, es verdad
What is the secondary prevention for platelet aggregation inhibitor use?
Prevent RECURRENCES of: TIA, CVA, MI, ACS
What are agents of fibrinolytics?
Which drug is a recombinant- tPA (r-tPA)?
What are therapeutic indications for fibrinolytics?
Peripheral arterial occlusion
T/F: Older clots are resistance to t-PA, that is why stroke treatment is very time sensitive
True; older clots are more resistance perhaps due to more fibrin cross-linking
What are agents of fibrinolysis inhibitors?
What do aminocaproic acid and tranexamic acid do?
They stop fibrinolysis meaning that it prevents the breakdown of the clot and blood continues to coagulate
What is the MOA of aminocaproic acid/ tranexamic acid?
Bind to plasminogen and prevents its conversion to plasmin
T/F: Unfractionated heparin, LMWH and Indirect Factor Xa inhibitor all have similar MOA
True; which is to inactivate thrombin and factor Xa
Heparin molecule must be at least ___ saccharides in length to inactivate thrombin
Heparin binds to _____ to speed up the inactivation of these clotting factors:___,___,____,___,____.
Factor IIa (thrombin)
T/F: unfractionated heparin is taken orally
False; parenteral administration: SubQ, IV bolus, constant IV infusion
What is the average elimination half life for heparin?
Time to steady state with constant IV infusion of heparin is ____ hours
6 (4x the half-life which is 1.5 hours)
Reversal agent for heparin and LMWH is:
Protamine – obtained from sperm of salmon
T/F: when administered alone, protamine has an anticoagulant effect
True; even though when used as a reversal for heparin it losses its anticoagulant activity
T/F: Heparin, LMWH and fondaparinux are safe for pregnant lady
True; these are safe for baby
MOA of Heparin-induced thrombocytopenia: ____ binds onto heparin which binds onto Ig____. The immune complex then bind onto Fc region of_____ which results in removal of it by _____ in the spleen. Can also result in platelet aggregation leading to ____
PF4 (platelet factor 4)
If HIT occurs in a patient, use ________, do not use___
IV direct thrombin inhibitor – ie Argatroban
Do not use heparin or LMWH
Which anticoagulant interfere with Vitamin K oxide reductase
Warfarin use would lead to decreased production of which clotting factors? Why?
Factors 7,9,10 and thrombin (IIa) [as well as anticoagulant proteins C and S]
Because these are vitamin K dependent
T/F: Warfarin has effect on already-synthesized clotting factors (2, 7, 9, 10)
False; it cannot affect already synthesized clotting factors that is why therapeutic effects for heparin are not seen until those factors are depleted (usually 3-4 days)
Elimination half lives of Factor II is ___ hours, and Factor X is ____ hours
T/F: Drop in concentration from warfarin action potentially can cause clotting early in therapy
True; warfarin is freaking weird. Early on is prothrombotic which means it can cause blood clots
Dosing of warfarin, must follow ____ result. Which is calculated by_____
INR= (Prothrombin time/ lab normal Prothrombin time)^ISI
ISI= international sensitivity index
Warfarin is metabolized by which organ?
Half life of warfarin is:
36 hours (1.5 days)
Fresh frozen plasma
Vitamin K : phytonadione
Prothrombin complex concentrate
T/F: warfarin is safe to use in pregnant women
False; unlike heparin/LMWH/fondaparinux, warfarin is bad, unless you are a pregnant woman with mechanical heart valves
T/F: vitamin K is fat soluble, so given too much as a warfarin reversal could lead to difficulty to re-anticoagulate for a while
For life-threatening bleed from warfarin, what is the treatment?
Give Fresh frozen plasma, prothrombin complex concentrate or factor VIIa in addition to IV vitamin K
Rank from greatest molecular weight to least: LMWH, Fondaparinux and heparin (UFH)