Anticoagulants - Dr. Issar Flashcards
After platelet activation, mediators like what are released, which further activate other platelets?
- ADP
2. 5-HT (serotonin)
Platelet activation expressed which receptors on the platelet surfaces?
GP IIB/ IIIA
GP IIB / IIIA binds to what?
Circulating fibrinogen
Tissue factor is a co-factor for which clotting factor?
Factor VII
Unfractioned heparin binds to antithrombin III and inactivates what 3 clotting factors?
- Thrombin
- X a
- IX a
What part of the unfractioned heparin binds to the antithrombin III?
pentasaccharide sequence
Fondaparinux selectively inhibits what?
Factor Xa
Why would LMWH/ Fondaparinux NOT inactivate thrombin?
The chain is too short to bridge AT III to thrombin
All heparins are metabolized in the liver by what enzyme?
Heparinase
LMWH & Fondaparinux are given as prophylactic therapy for what?
DVTs
What are the advantages of LMWH?
- Less bleeding
- A longer half-life
- no lab monitoring required
What is the black box warning for LMWH?
Can cause spinal/ epidural hematomas
What is the common side effect of heparins?
Hemorrhage
What could be an antidote to excess heparin?
Promatine
How does Promatine work?
It neutralizes the negative charge of heparin
Protamine has NO effect on what indirect thrombin inhibitor?
Fondapurnix
What is the rare and fatal side effect of heparins?
Immune mediated HIT
In immune mediated HIT, the body produces IgG antibodies against what?
heparin- platelet factor 4 complexes
The direct thrombin inhibitors, Lepirudin, Desirudin, and Bivalirudin, bind to which sites on thrombin?
- Enzymatic active site
2. Exosite
What makes Lepirudin highly effective?
- it inhibits both free & fibrin bound thrombin
2. irreversibly binds to thrombin
