Antithrombotics (1) (1) Flashcards
What is the primary function of blood in the vasculature?
Blood remains fluid within the vasculature but clots quickly when exposed to non-endothelial surfaces at sites of vascular injury.
What system is activated when an intravascular thrombus occurs?
A system of fibrinolysis is activated to restore blood fluidity.
What balance prevents both thrombosis and hemorrhage?
A delicate balance between pro-coagulants and anticoagulants.
What can offset the desired therapeutic effect of anticoagulants?
The toxic effect of bleeding caused by overdosing of an anticoagulant.
In general, how can antithrombotics be categorized?
Antithrombotics can be divided into:
* Anticoagulants
* Antiplatelet agents
* Thrombolytic drugs
What is Heparin and how is it administered?
Heparin is a glycosaminoglycan found in secretory granules of mast cells and is administered parenterally.
What is the role of Heparin in coagulation?
Heparin stimulates anti-thrombin and inhibits coagulation proteases by anti-thrombin.
What type of drug is Lepirudin?
A recombinant derivative of hirudin, a direct thrombin inhibitor.
What distinguishes Bivalirudin from Lepirudin?
Bivalirudin is a synthetic polypeptide that directly inhibits thrombin.
What is the mechanism of action of Argatroban?
Argatroban is a synthetic compound that binds reversibly to the catalytic site of thrombin.
What does Danaparoid inhibit?
Danaparoid promotes inhibition of factor Xa by antithrombin.
What is the function of Drotrecogin Alpha?
It inhibits coagulation by proteolytic inactivation of factors Va and VIIIa.
What type of drug is Warfarin?
A coumarin derivative that antagonizes vitamin K.
What is the plasma half-life of Phenprocoumon compared to Warfarin?
Phenprocoumon has a longer plasma half-life (5 days) than Warfarin.
What are Indandione derivatives used for?
Used as anticoagulants in Europe and elsewhere.
What is Ximelagatran and how does it compare to Warfarin?
Ximelagatran is rapidly metabolized to Melagatran and has a faster action than Warfarin.
What do fibrinolytic drugs do?
Convert plasminogen to plasmin, which degrades fibrin and dissolves the thrombus.
What is the role of Streptokinase in fibrinolysis?
It produces a conformational change that exposes the active site on plasminogen to form free plasmin.
What is the action of Urokinase?
A serine protease that cleaves plasminogen to plasmin.
How are antiplatelet drugs classified?
Based on their mechanism of action, such as platelet aggregation inhibitors.
What is the mechanism of action of Aspirin?
It inhibits cyclooxygenase (COX), reducing platelet aggregation.
What are thienopyridines used for?
They selectively inhibit ADP-induced platelet aggregation.
Name examples of thienopyridines.
Clopidogrel, Ticagrelor, Ticlopidine, and Prasugrel.
What is the most potent thienopyridine?
Prasugrel.
