AUSTIN - part 2: Anticoagulants

What is the mechanism of action of warfarin?

• A) Directly inhibits thrombin

• B) Inhibits vitamin K epoxide reductase (VKOR)

• C) Binds to antithrombin III to inhibit Factor Xa

• D) Directly inhibits platelet aggregation

B

Which clotting factors require vitamin K for activation?

• A) Factors I, II, V, and VIII

• B) Factors III, IV, VII, and IX

• C) Factors II, VII, IX, and X

• D) Factors V, VIII, XI, and XIII

C

What laboratory test is used to monitor warfarin therapy?

• A) Activated Partial Thromboplastin Time (aPTT)

• B) Prothrombin Time (PT)/International Normalized Ratio (INR)

• C) Anti-Factor Xa Assay

• D) Thrombin Time (TT)

B

Which of the following increases warfarin’s anticoagulant effect?

• A) Rifampin

• B) St. John’s Wort

• C) CYP2C9 inhibitors (e.g., amiodarone)

• D) High vitamin K diet

C

What is the reversal agent for warfarin-induced bleeding?

• A) Heparin

• B) Protamine sulfate

• C) Vitamin K

• D) Aspirin

C

What is the major disadvantage of warfarin therapy?

• A) Short half-life

• B) No need for monitoring

• C) Narrow therapeutic index

• D) Rapid onset of action

C

Which of the following is an advantage of direct oral anticoagulants (DOACs) over warfarin?

• A) Requires frequent INR monitoring

• B) More food and drug interactions

• C) Faster onset of action

• D) Increased risk of drug accumulation

C

Which factor does unfractionated heparin (UFH) primarily inhibit?

• A) Factor VII

• B) Factor Xa and thrombin

• C) Factor XIII

• D) Factor IIa only

B

Which test is used to monitor unfractionated heparin therapy?

• A) INR

• B) aPTT

• C) Anti-Factor Xa Assay

• D) D-dimer

B

1. What is the primary advantage of low molecular weight heparins (LMWHs) over UFH?

• A) Requires intravenous administration

• B) Longer half-life and more predictable dosing

• C) Increased risk of heparin-induced thrombocytopenia (HIT)

• D) More need for aPTT monitoring

B

11. Which anticoagulant is a synthetic pentasaccharide that selectively inhibits Factor Xa via antithrombin III?

• A) Warfarin

• B) Dabigatran

• C) Fondaparinux

• D) Enoxaparin

C

12. Which condition is a potential side effect of heparin therapy?

• A) Thrombocytopenia

• B) Hyperkalemia

• C) Osteoporosis

• D) All of the above

D

13. What is the antidote for heparin overdose?

• A) Vitamin K

• B) Andexanet alfa

• C) Protamine sulfate

• D) Idarucizumab

C

14. Which anticoagulant is a direct thrombin inhibitor?

• A) Rivaroxaban

• B) Apixaban

• C) Dabigatran

• D) Warfarin

C

15. Which of the following direct Factor Xa inhibitors requires food for proper absorption at higher doses?

• A) Dabigatran

• B) Apixaban

• C) Rivaroxaban

• D) Warfarin

C

16. Which direct Factor Xa inhibitor has a specific reversal agent available?

• A) Warfarin

• B) Apixaban

• C) Rivaroxaban

• D) Both B and C

• D (Reversal agent: Andexanet alfa)

17. Why does dabigatran require an acidic environment for absorption?

• A) It is a direct Factor Xa inhibitor

• B) It requires P-glycoprotein for transport

• C) It is a prodrug and contains tartaric acid in its formulation

• D) It has a high bioavailability

C

18. Which of the following anticoagulants is least dependent on renal clearance?

• A) Dabigatran

• B) Apixaban

• C) Rivaroxaban

• D) Fondaparinux

B

19. Which of the following statements about heparin-induced thrombocytopenia (HIT) is true?

• A) It occurs less frequently with LMWH than UFH

• B) Type 1 HIT is an immune-mediated reaction

• C) It is associated with an increased risk of bleeding but not clotting

• D) It occurs more frequently with fondaparinux than UFH

A

20. What is the preferred anticoagulant for a patient with a history of HIT?

• A) Warfarin

• B) Unfractionated heparin

• C) Fondaparinux

• D) LMWH

C