Deep vein thrombosis: prevention and anticoagulant therapy MCQs With Answer

This question bank focuses on deep vein thrombosis (DVT) prevention and anticoagulant therapy tailored for M.Pharm students studying Pharmacotherapeutics I (MPP 102T). The set provides clinically relevant, mechanism-based multiple-choice questions covering heparins, vitamin K antagonists, direct oral anticoagulants, monitoring strategies, reversal agents, perioperative prophylaxis, special populations (pregnancy, renal impairment), and complications such as heparin‑induced thrombocytopenia. Each item is designed to test applied pharmacology, dosing principles, laboratory monitoring, drug interactions, and guideline-based prophylaxis and management. Use these MCQs to deepen understanding of anticoagulant selection, monitoring and complication management in DVT prevention and treatment.

Q1. Which statement best describes the pharmacologic difference between low molecular weight heparin (LMWH) and unfractionated heparin (UFH)?

• LMWH has a higher anti‑Xa to anti‑IIa activity ratio compared with UFH
• LMWH primarily inhibits thrombin with no effect on factor Xa
• UFH directly inhibits factor Xa without antithrombin mediation
• UFH and LMWH have identical anti‑Xa:anti‑IIa ratios

Correct Answer: LMWH has a higher anti‑Xa to anti‑IIa activity ratio compared with UFH

Q2. Which laboratory test is preferred for monitoring therapeutic anticoagulation in a patient receiving LMWH in special populations (e.g., pregnancy, obesity, renal impairment)?

• Activated partial thromboplastin time (aPTT)
• Prothrombin time (PT)
• Anti‑factor Xa activity assay
• Fibrinogen level

Correct Answer: Anti‑factor Xa activity assay

Q3. What is the primary mechanism by which warfarin exerts its anticoagulant effect?

• Direct inhibition of thrombin (factor IIa)
• Activation of antithrombin III leading to factor Xa inhibition
• Inhibition of vitamin K epoxide reductase, reducing gamma‑carboxylation of vitamin K‑dependent clotting factors
• Direct binding and inhibition of factor Xa

Correct Answer: Inhibition of vitamin K epoxide reductase, reducing gamma‑carboxylation of vitamin K‑dependent clotting factors

Q4. In a patient with life‑threatening bleeding on warfarin, the guideline‑recommended rapid reversal includes which of the following?

• Oral vitamin K alone
• Fresh frozen plasma only
• Prothrombin complex concentrate (PCC) plus intravenous vitamin K
• Protamine sulfate

Correct Answer: Prothrombin complex concentrate (PCC) plus intravenous vitamin K

Q5. Which anticoagulant is contraindicated in patients with mechanical heart valves due to increased thrombotic and bleeding events observed in trials?

• Warfarin
• Dabigatran (direct thrombin inhibitor)
• Enoxaparin (LMWH)
• Rivaroxaban (direct factor Xa inhibitor)

Correct Answer: Dabigatran (direct thrombin inhibitor)

Q6. For suspected heparin‑induced thrombocytopenia (HIT), the immediate management should include which action?

• Continue heparin and start platelet transfusion
• Stop all heparin products and initiate a non‑heparin parenteral anticoagulant such as argatroban
• Start low molecular weight heparin instead
• Administer protamine sulfate and resume warfarin immediately

Correct Answer: Stop all heparin products and initiate a non‑heparin parenteral anticoagulant such as argatroban

Q7. Which pharmacologic prophylaxis is recommended as first‑line for DVT prevention after major orthopedic surgery (e.g., total hip replacement)?

• Low‑molecular‑weight heparin (LMWH)
• Low‑dose aspirin only
• Warfarin without monitoring
• No prophylaxis is recommended

Correct Answer: Low‑molecular‑weight heparin (LMWH)

Q8. Rivaroxaban and apixaban exert anticoagulant effects by which mechanism?

• Direct inhibition of thrombin (factor IIa)
• Indirect inhibition of factor Xa via antithrombin activation
• Direct reversible inhibition of factor Xa
• Inhibition of vitamin K recycling

Correct Answer: Direct reversible inhibition of factor Xa

Q9. Which statement is true regarding routine laboratory monitoring for patients on direct oral anticoagulants (DOACs) such as apixaban or rivaroxaban?

• Routine INR monitoring is required weekly
• Routine anti‑Xa monitoring is mandatory for all patients
• No routine coagulation monitoring is required in most patients
• Daily aPTT testing is recommended

Correct Answer: No routine coagulation monitoring is required in most patients

Q10. Which anticoagulant is preferred for DVT prophylaxis and treatment during pregnancy?

• Warfarin throughout pregnancy
• Low‑molecular‑weight heparin (LMWH)
• Dabigatran
• Rivaroxaban

Correct Answer: Low‑molecular‑weight heparin (LMWH)

Q11. After initiating warfarin, which clotting factor shows the earliest decline in activity due to its shortest half‑life?

• Factor II (prothrombin)
• Factor VII
• Factor X
• Protein S

Correct Answer: Factor VII

Q12. Protamine sulfate is used to reverse heparin effects. Which statement is correct regarding its activity?

• Protamine fully reverses both UFH and LMWH equally
• Protamine fully reverses UFH and partially reverses LMWH
• Protamine reverses warfarin anticoagulation
• Protamine is ineffective against UFH

Correct Answer: Protamine fully reverses UFH and partially reverses LMWH

Q13. Placement of an inferior vena cava (IVC) filter is most appropriate in which clinical scenario?

• First‑line for all patients with provoked DVT
• Patients with acute DVT and ongoing pulmonary embolism despite therapeutic anticoagulation
• Patients with acute DVT who have an absolute contraindication to anticoagulation
• As prophylaxis in all high‑risk surgical patients

Correct Answer: Patients with acute DVT who have an absolute contraindication to anticoagulation

Q14. Which laboratory parameter is used to monitor and dose-adjust warfarin therapy?

• Activated partial thromboplastin time (aPTT)
• Platelet count
• International Normalized Ratio (INR)
• Serum fibrinogen

Correct Answer: International Normalized Ratio (INR)

Q15. In a patient with severe renal impairment (creatinine clearance <30 mL/min) requiring anticoagulation for acute DVT, which approach is most appropriate?

• Use standard therapeutic dosing of enoxaparin without adjustment
• Prefer unfractionated heparin (UFH) due to easier titration and shorter half‑life
• Use rivaroxaban at full dose without monitoring
• Fondaparinux is preferred without dose change

Correct Answer: Prefer unfractionated heparin (UFH) due to easier titration and shorter half‑life

Q16. Fondaparinux exerts its anticoagulant effect by which mechanism?

• Direct inhibition of thrombin (factor IIa)
• Synthetic pentasaccharide that binds antithrombin III to selectively inhibit factor Xa
• Inhibition of vitamin K epoxide reductase
• Activation of protein C

Correct Answer: Synthetic pentasaccharide that binds antithrombin III to selectively inhibit factor Xa

Q17. How long does it generally take to achieve the full anticoagulant effect of warfarin after initiation?

• Within 1–2 hours of the first dose
• Within 12 hours
• Typically 5–7 days to reach full effect due to clotting factor half‑lives
• It has no delayed onset and is immediately therapeutic

Correct Answer: Typically 5–7 days to reach full effect due to clotting factor half‑lives

Q18. Which drug combination most markedly increases the risk of major bleeding in patients receiving anticoagulation for DVT?

• Warfarin combined with aspirin or other antiplatelet agents
• LMWH combined with folic acid
• Rivaroxaban combined with vitamin D
• Apixaban combined with calcium supplements

Correct Answer: Warfarin combined with aspirin or other antiplatelet agents

Q19. What is the specific reversal agent for dabigatran in the setting of life‑threatening bleeding?

• Idarucizumab
• Andexanet alfa
• Protamine sulfate
• Vitamin K

Correct Answer: Idarucizumab

Q20. Genetic polymorphisms can influence warfarin dosing. Which gene variant is primarily associated with reduced warfarin metabolism and lower dose requirements?

• VKORC1 polymorphism causing increased vitamin K recycling
• CYP2C9 loss‑of‑function variants (e.g., *2, *3) leading to reduced warfarin metabolism
• F5 Leiden mutation
• Prothrombin G20210A mutation

Correct Answer: CYP2C9 loss‑of‑function variants (e.g., *2, *3) leading to reduced warfarin metabolism

Download