Heparins and Antithrombin Activity Quiz

Play an AI-generated podcast conversation about this lesson

What is the main mechanism of action of heparins in promoting anticoagulation?

Activating platelets via FcγIIa receptors

Binding to circulating platelet factor 4 (PF4)

Enhancing the activity of antithrombin (correct)

Forming stable salts with sulfate protamine

Why have drugs like enoxaparin largely replaced unfractionated heparin (UFH) in clinical use?

Increased binding to plasma and endothelial proteins

Shorter half-life

Higher risk of bleeding

Improved bioavailability (correct)

What is the biggest disadvantage associated with the use of UFH and LMWHs?

Potential for allergic reactions

Development of heparin-induced thrombocytopenia (HIT) (correct)

Risk of hypercoagulability

High cost

Why is fondaparinux considered an appealing alternative to UFH and LMWHs?

Similar pharmacological characteristics with lower risk of HIT Signup and view all the answers

What is the origin of unfractionated heparin (UFH)?

Obtained from liver, lung, mast cells, and other cells of vertebrates Signup and view all the answers

How is the protein binding of enoxaparin different from UFH?

UFH has 94% protein binding specifically to antithrombin Signup and view all the answers

What is the advantage of Vitamin K Antagonists (VKAs) over parenterally administered heparins?

They can be administered orally Signup and view all the answers

Which anticoagulant requires sulfate protamine as a neutralizing agent in case of overdose?

UFH Signup and view all the answers

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 Signup and view all the answers

Why are Vitamin K antagonists (VKAs) suitable for oral administration?

They compete with vitamin K for recycling in the bloodstream Signup and view all the answers

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 Signup and view all the answers

Which coagulation factor is dependent on vitamin K for its conversion from an inactive zymogen to an active enzyme?

Factor IX Signup and view all the answers

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 Signup and view all the answers

What is the role of VKCOR1 in the context of vitamin K-dependent coagulation factors?

Reducing vitamin K to its active form Signup and view all the answers

Why is monitoring the international normalized ratio (INR) crucial during VKA treatment?

To adjust the dosage of VKA based on the patient's response Signup and view all the answers

How does exogenous vitamin K act as a neutralizing agent for VKAs?

By reversing the anticoagulant effects of VKAs Signup and view all the answers

What is the main difference between bivalirudin and argatroban compared to UFH and LMWH?

They possess a lower immunogenic profile. Signup and view all the answers

How is the elimination process of bivalirudin different from that of warfarin?

Via kidney or proteolytic cleavage. Signup and view all the answers

What is the target of bivalirudin and argatroban in the context of anticoagulation?

Thrombin Signup and view all the answers

Which anticoagulant has already reached peak activity within minutes after injection?

Bivalirudin Signup and view all the answers