20 Questions
What is the main mechanism of action of heparins in promoting anticoagulation?
Enhancing the activity of antithrombin
Why have drugs like enoxaparin largely replaced unfractionated heparin (UFH) in clinical use?
Improved bioavailability
What is the biggest disadvantage associated with the use of UFH and LMWHs?
Development of heparin-induced thrombocytopenia (HIT)
Why is fondaparinux considered an appealing alternative to UFH and LMWHs?
Similar pharmacological characteristics with lower risk of HIT
What is the origin of unfractionated heparin (UFH)?
Obtained from liver, lung, mast cells, and other cells of vertebrates
How is the protein binding of enoxaparin different from UFH?
UFH has 94% protein binding specifically to antithrombin
What is the advantage of Vitamin K Antagonists (VKAs) over parenterally administered heparins?
They can be administered orally
Which anticoagulant requires sulfate protamine as a neutralizing agent in case of overdose?
UFH
Which of the following accurately describes the mechanism of action of Vitamin K antagonists (VKAs)?
Compete with vitamin K epoxide reductase to deplete circulating vitamin K
Why are Vitamin K antagonists (VKAs) suitable for oral administration?
They compete with vitamin K for recycling in the bloodstream
How does Fondaparinux differ from unfractionated heparin (UFH) and low molecular weight heparins (LMWHs) in terms of structure?
It contains specific pentasaccharide sequence binding to antithrombin
Which coagulation factor is dependent on vitamin K for its conversion from an inactive zymogen to an active enzyme?
Factor IX
Why does VKA treatment typically require a bridging period with a fast-acting heparin?
To counteract the transient depletion of the circulating vitamin K pool
What is the role of VKCOR1 in the context of vitamin K-dependent coagulation factors?
Reducing vitamin K to its active form
Why is monitoring the international normalized ratio (INR) crucial during VKA treatment?
To adjust the dosage of VKA based on the patient's response
How does exogenous vitamin K act as a neutralizing agent for VKAs?
By reversing the anticoagulant effects of VKAs
What is the main difference between bivalirudin and argatroban compared to UFH and LMWH?
They possess a lower immunogenic profile.
How is the elimination process of bivalirudin different from that of warfarin?
Via kidney or proteolytic cleavage.
What is the target of bivalirudin and argatroban in the context of anticoagulation?
Thrombin
Which anticoagulant has already reached peak activity within minutes after injection?
Bivalirudin
Test your knowledge on heparins, antithrombin activity, and the use of protamine in diminishing anticoagulant potential. Learn about the limitations and characteristics of unfractionated heparin (UFH) compared to low molecular weight heparins (LMWHs).
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