Anticoagulants, Antiplatelets, and Thrombolytics- leblanc Flashcards
(146 cards)
What are some anticoagulants?
- Unfractionated or high molecular weight heparin
- low molecular weight heparins
- factor IIa and Xa inhibitors
- Warfarin (coumadin)
What is a procoagulant?
desmopressin acetate
What are some antiplatelet drugs?
Acetylsalicylic acid (aspirin) Clopidogrel bisulfate (Plavix) Abciximab (ReoPro)
What are some thrombolytic agents?
Tissue plasminogen activator (t-PA)
What are some antagonists?
Protamine sulfate
Aminocaproic acid
T or F
under normal physiological conditions, little or no intravascular coagulation occurs
T
Why don’t you have intravascular coagulation under normal physiological conditions?
- Dilution
- Presence of plasma inhibitors
- activated clotting factors are rapidly removed by the liver
When vascular damage occurs, several physiologic reactions participate to contrl blood loss?
Platelet adhesion reaction Platelet activation Platelet aggregation Formation of a clot (coagulatio) Fibrinolysis
What are the three major risk factors for thromboembolism?
- abnormalities of blood flow
- abnormalities of surfaces in contact with blood
- abnormalities of clotting components
How do you get vasoconstriction or vasospasm in hemostasis?
thomboxane A2 (TA2) and serotonin (5-HT) released by platelets which triggers powerful constrictions stimulating the contraction of smooth muscle cells within the walls of blood vessels
What is this:
coagulation occurs due to trauma originating from the extra-vascular space (formation of a macromolecular complex involving thromboplastin or tissue factor, and factor VII); the most important in vivo.
Extrinsic Pathway
What is this:
coagulation is triggered by trauma to the blood itself (from large glycoprotein complexes released by platelets)
Intrinisic pathway
What does t-PA and urokinase do?
upregulated plasmin to degrade blood clots (degrades fibrin, fibrinogen)
So tell me what happens if you have a damaged vessel wall?
platelet adhesion and initiation of coagulation
If you get platelet adhesion and thrombin what happens next?
you get release of mediators which will cause platelet aggregtes and fibrin
What will platelet aggregates and fibrin cause?
a thrombus
What will a thrombus induce?
fibrinolysis which will degrade products
What three major categories of anticoagulant drugs?
Direct acting anticoagulants
Indirect acting anticoagulants
Antiplatelet agents
What are some examples of direct acting anticoagulants?
Calcium Chelators (useful for in vitro testing; sodium citrate, EDTA)
Heparin (unfractionated and low molecular weight fractions)
Factor IIa and Xa inhibitors
What is an example of an indirect acting anticoagulants?
warfarin (coumadin)
What is an example of an antiplatelet agent?
aspirin, plavix
What are the clinical tests for assessing antiplatelet, anticoagulant and thrombolytic therapies?
Bleeding time
platelet count (normal: 150,000-400,000)
Pro-thrombin time (PT)
What does pro-thrombin time tell you?
reflects alterations in the extrinsic pathway
What is a normal pro-thrombin time?
12 seconds