Flashcards in Anti-platelet, anti-coagulant and thrombolytic drugs Deck (43)
Which clotting factor is factor 2?
What kind of thrombus is a white thrombus? (Arterial/venous)
What kind of thrombus is a red thrombus? (Arterial/venous)
Which organs do white thromboemboli generally tend to occlude the blood supply to?
Where do red thromboemboli tend to lodge?
What is the definition of thrombosis?
What kind of precursors are clotting factors 2, 7, 9 and 10?
What do the active factors 2a, 7a, 9a and 10a act as?
What need to occur to allow transformation of precursors to clotting factors? E.g. prothrombin to thrombin.
Gamma carboxylation (of glutamate residues)
What process does Vitamin K allow to occur and what does this facilitate?
Gamma carboxylation, facilitating the conversion of precursors to active clotting factors e.g. prothrombin to thrombin
Which form of Vitamin K is required to allow gamma carboxylation to occur? (Oxidised/reduced)
Reduced form - a hydroquinone
Which enzyme converts vitamin K from it's oxidised form to it's reduced form?
Vitamin K reductase
Which enzyme does the drug warfarin target?
Vitamin K reductase
What can be used to counteract Warfarin when dose is too high?
What drug may be added to dose of warfarin to produce rapid anticoagulant effect?
What scale is used to ensure that the correct dose of warfarin has been given?
International normalised ratio
Why is haemorrhage more likely with warfarin in a patient with existing liver disease?
The liver produces clotting factors
Which molecule in the body acts to stop the coagulation cascade naturally?
How does antithrombin 3 act to stop the coagulation cascade?
It binds directly to the active site of active thrombin and inhibits it
How does heparin work?
Heparin binds to antithrombin III, increasing its affinity for serine protease clotting factors (particularly Xa and IIa (thombin) to greatly increase their rate of their inactivation
To inactivate factor 2a, what must heparin bind to?
Both antithrombin 3 and thrombin
To inactivate factor 10, what must heparin bind to?
What clotting factor does low molecular weight heparin inhibit?
Where does excretion of LMWH occur?
Which drug - heparin or LMWH - shows zero order kinetics?
Which drug - heparin or LMWH - shows first order kinetics?
Which drug - heparin or LMWH - is preferred in renal failure and why?
Heparin - LMWH excreted via renal system
How does rivaroxiban work?
Directly inhibitis Xa
When is rivaroxiban used in treatment?
After hip and knee surgeries to prevent formation of venous clot