ADP Receptor Antagonists: Clopidogrel and Abciximab

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What is the mechanism of action of fondaparinux?

It accelerates the normal rate of inactivation of active clotting factors by prothrombin

It inactivates factor Xa only (correct)

It inactivates both thrombin and Xa equally

It serves as a catalytic surface for antithrombin and thrombin

How does fondaparinux differ from heparin in terms of selectivity?

Heparin inactivates thrombin and Xa equally (correct)

Heparin inactivates factor Xa poorly

Fondaparinux inactivates thrombin and Xa equally

Heparin inactivates factor Xa only

How is the onset of anticoagulant effect for fondaparinux described?

Is immediately effective upon oral administration

Has a delayed onset after SC administration

Occurs rapidly within minutes of IV administration (correct)

Occurs slowly over hours after IV administration

What is the clearance route for LMWH and fondaparinux?

Cleared by the kidneys (C) Signup and view all the answers

When are LMWH and fondaparinux usually indicated over heparin?

In patients requiring rapid onset and short duration of action (A) Signup and view all the answers

What is the primary target for fondaparinux inactivation?

Factor Xa (C) Signup and view all the answers

Which type of cells does heparin bind to?

Endothelial cells (C) Signup and view all the answers

LMWH and fondaparinux do not require monitoring because:

They have a longer half-life than heparin (D) Signup and view all the answers

Heparin is usually given by which route of administration?

IV infusion (B) Signup and view all the answers

How does fondaparinux differ from LMWH in terms of inactivation?

Fondaparinux inactivates factor Xa only (B) Signup and view all the answers

What is the primary mechanism through which fondaparinux exerts its anticoagulant effect?

Enhancing antithrombin activity towards target proteases (D) Signup and view all the answers

How is heparin mainly cleared from the body?

By cellular uptake by mononuclear cells (D) Signup and view all the answers

What distinguishes the pharmacokinetics of LMWH/fondaparinux from heparin?

They have longer half-lives and are cleared by the kidneys (A) Signup and view all the answers

What is the primary advantage of using fondaparinux during outpatient transition to warfarin?

Rapid onset and short duration of action (C) Signup and view all the answers

Why is LMWH preferred over heparin for certain indications?

LMWH inactivates factor Xa better than thrombin (D) Signup and view all the answers

Which of the following statements about the mechanism of fondaparinux is correct?

Fondaparinux makes the catalytic site of antithrombin more accessible (A) Signup and view all the answers

'Circulating thrombin only, no clot bound' describes which aspect of fondaparinux's mechanism?

'Blocks formation of fibrin' (A) Signup and view all the answers

'Parenteral' anticoagulant refers to medications that are typically administered through which route?

[Subcutaneously] (C) Signup and view all the answers

What is one advantage of using LMWH/fondaparinux over heparin in terms of monitoring requirements?

Do not necessitate regular monitoring for therapeutic effect (A) Signup and view all the answers

What is the mechanism of action of abciximab (ReoPro®)?

Blocks platelet aggregation by blocking GPIIb/IIIa receptors (A) Signup and view all the answers

What is the pharmacokinetics of vorapaxar (Zontivity®)?

Onset of action within 1 week, effects may last up to 4 weeks after stopping (D) Signup and view all the answers

What is the primary therapeutic use of abciximab (ReoPro®)?

Prevent ischemic events in patients with ACS or undergoing PCI (B) Signup and view all the answers

Which adverse effect is specifically associated with vorapaxar (Zontivity®)?

Intracranial hemorrhage and fatal bleeding (D) Signup and view all the answers

How does abciximab (ReoPro®) achieve a long duration of action despite a short half-life?

Forms irreversible bonds with platelets (A) Signup and view all the answers

In what way does vorapaxar (Zontivity®) differ from abciximab (ReoPro®) in terms of therapeutic use?

Vorapaxar reduces thrombotic events in patients post-MI, whereas abciximab prevents ischemic events in patients undergoing PCI (C) Signup and view all the answers

Which of the following accurately describes the mechanism of action of fondaparinux?

Indirectly accelerates the inactivation of active clotting factors by antithrombin (B) Signup and view all the answers

What distinguishes the pharmacokinetics of heparin from LMWH/fondaparinux?

Heparin requires frequent monitoring unlike LMWH/fondaparinux (D) Signup and view all the answers

What is the main selective action of fondaparinux compared to heparin and LMWH?

Inactivates factor Xa only (C) Signup and view all the answers

During which medical procedures is fondaparinux commonly used to prevent thrombosis?

Renal hemodialysis (B) Signup and view all the answers

What is the route of administration for heparin that distinguishes it from LMWH/fondaparinux?

Intravenous infusion (B) Signup and view all the answers

Which of the following statements accurately describes the onset of anticoagulant effect in fondaparinux?

Anticoagulant effect occurs within minutes of subcutaneous administration (B) Signup and view all the answers

What is the mechanism of action of clopidogrel (Plavix®)?

Binds irreversibly to platelet P2Y12 ADP receptor (B) Signup and view all the answers

Which statement regarding clopidogrel's pharmacokinetics is accurate?

Maximal efficacy occurs 8-11 days after starting therapy (A) Signup and view all the answers

In which patient population is clopidogrel indicated for use?

Patients with a history of stroke or myocardial infarction (C) Signup and view all the answers

Which adverse effect is associated with clopidogrel use?

Thrombotic thrombocytopenic purpura (D) Signup and view all the answers

How does clopidogrel compare to aspirin in terms of efficacy and cost?

Clopidogrel is slightly better in efficacy but much more expensive than aspirin (A) Signup and view all the answers

What is the primary role of ADP receptor antagonists like clopidogrel in combination with aspirin?

Prevent coronary stent thrombosis and ACS (C) Signup and view all the answers