Coagulants and anticoagulants – Menadione MCQs With Answer

Coagulants and anticoagulants – Menadione MCQs With Answer

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This focused set of Coagulants and anticoagulants – Menadione MCQs With Answer is designed for B. Pharm students to deepen understanding of coagulation pharmacology. Topics include mechanisms of action, the vitamin K cycle, menadione pharmacology, VKORC1-mediated warfarin resistance, gamma‑carboxylation of clotting factors, clinical uses of coagulants and anticoagulants, monitoring parameters (INR, aPTT), dosing, drug–drug interactions, adverse effects, and antidotes like vitamin K and protamine. Questions emphasize critical thinking about heparins, VKAs, DOACs, and menadione’s role in correcting coagulopathies. Each MCQ reinforces therapeutic choices, lab interpretation, and safety considerations relevant to pharmacy practice. Now let’s test your knowledge with 30 MCQs on this topic.

Q1. Which compound is known as menadione and historically considered a synthetic vitamin K analogue?

  • Phylloquinone (vitamin K1)
  • Menadione (vitamin K3)
  • Menaquinone (vitamin K2)
  • Phytonadione (vitamin K1 injectable)

Correct Answer: Menadione (vitamin K3)

Q2. What is the primary biochemical role of vitamin K (including menadione) in coagulation?

  • Activation of plasminogen to plasmin
  • Gamma‑carboxylation of glutamate residues on clotting factors
  • Direct inhibition of thrombin activity
  • Stimulation of platelet aggregation via ADP release

Correct Answer: Gamma‑carboxylation of glutamate residues on clotting factors

Q3. Which enzyme is inhibited by warfarin leading to reduced recycling of vitamin K?

  • Gamma‑glutamyl carboxylase
  • Vitamin K epoxide reductase (VKORC1)
  • Prothrombinase complex
  • Thromboxane synthase

Correct Answer: Vitamin K epoxide reductase (VKORC1)

Q4. Menadione differs from phylloquinone mainly in which property relevant to clinical use?

  • Longer plasma half‑life than phylloquinone
  • Greater water solubility and higher toxicity risk
  • Specific inhibition of factor Xa
  • Strong anticoagulant activity independent of vitamin K cycle

Correct Answer: Greater water solubility and higher toxicity risk

Q5. Which laboratory test is most appropriate to monitor warfarin therapy?

  • Activated partial thromboplastin time (aPTT)
  • Platelet count
  • Prothrombin time expressed as INR
  • Fibrinogen level

Correct Answer: Prothrombin time expressed as INR

Q6. A patient on warfarin presents with major bleeding. Which therapy provides the fastest restoration of vitamin K–dependent clotting factors?

  • Oral phytonadione (vitamin K1)
  • Fresh frozen plasma or prothrombin complex concentrate (PCC)
  • Activated charcoal
  • Subcutaneous low molecular weight heparin

Correct Answer: Fresh frozen plasma or prothrombin complex concentrate (PCC)

Q7. Which adverse effect is specifically associated with menadione in susceptible individuals?

  • Heparin‑induced thrombocytopenia
  • Hemolytic anemia in G6PD deficiency
  • Taste disturbance and ototoxicity
  • Hypokalemia

Correct Answer: Hemolytic anemia in G6PD deficiency

Q8. Heparin exerts anticoagulant effects primarily by which mechanism?

  • Direct inhibition of factor Xa only
  • Activation of antithrombin III to inhibit thrombin and factor Xa
  • Blocking vitamin K epoxide reductase
  • Enhancement of platelet aggregation

Correct Answer: Activation of antithrombin III to inhibit thrombin and factor Xa

Q9. Which agent is the specific reversal antidote for dabigatran?

  • Idarucizumab
  • Protamine sulfate
  • Andexanet alfa
  • Vitamin K (phytonadione)

Correct Answer: Idarucizumab

Q10. Which laboratory assay is most useful to monitor unfractionated heparin therapy?

  • INR
  • Anti‑factor Xa level only
  • Activated partial thromboplastin time (aPTT)
  • D‑dimer

Correct Answer: Activated partial thromboplastin time (aPTT)

Q11. Low molecular weight heparins (LMWH) differ from unfractionated heparin by:

  • Preferential inhibition of factor Xa over thrombin and more predictable pharmacokinetics
  • Complete reversal by vitamin K
  • Primary inhibition of platelet aggregation
  • Causing more frequent heparin‑induced thrombocytopenia (HIT)

Correct Answer: Preferential inhibition of factor Xa over thrombin and more predictable pharmacokinetics

Q12. Which genetic factor most influences initial warfarin dose variability?

  • CYP3A4 polymorphisms only
  • CYP2C9 and VKORC1 polymorphisms
  • G6PD deficiency
  • HLA‑B*57:01 allele

Correct Answer: CYP2C9 and VKORC1 polymorphisms

Q13. Andexanet alfa is used clinically to reverse anticoagulation caused by:

  • Dabigatran (direct thrombin inhibitor)
  • Low molecular weight heparin
  • Factor Xa inhibitors such as rivaroxaban and apixaban
  • Warfarin

Correct Answer: Factor Xa inhibitors such as rivaroxaban and apixaban

Q14. Which clotting factors are vitamin K dependent?

  • Factors V, VIII, and XIII
  • Factors II, VII, IX, and X and proteins C and S
  • Factors I, III, and IV
  • Factors XI and XII

Correct Answer: Factors II, VII, IX, and X and proteins C and S

Q15. Which statement about menadione (vitamin K3) clinical use is correct?

  • Menadione is the preferred oral form for newborn prophylaxis worldwide
  • Menadione is widely used intravenously in humans due to excellent safety
  • Menadione has been limited in human use due to potential toxicity and hemolysis risk
  • Menadione directly inhibits VKORC1 like warfarin

Correct Answer: Menadione has been limited in human use due to potential toxicity and hemolysis risk

Q16. Protamine sulfate reverses anticoagulation by which drug most effectively?

  • Warfarin
  • Unfractionated heparin
  • Rivaroxaban
  • Dabigatran

Correct Answer: Unfractionated heparin

Q17. A prolonged INR with normal aPTT suggests deficiency or inhibition of which pathway?

  • Intrinsic pathway
  • Extrinsic pathway or vitamin K–dependent factors
  • Common pathway only
  • Primary fibrinolysis

Correct Answer: Extrinsic pathway or vitamin K–dependent factors

Q18. Which clinical scenario requires neonatal vitamin K prophylaxis to prevent hemorrhagic disease of the newborn?

  • Administration of menadione to breastfeeding mothers only
  • Routine intramuscular vitamin K (phytonadione) to newborns at birth
  • Giving oral warfarin to newborns
  • Avoiding all vitamin K to stimulate endogenous synthesis

Correct Answer: Routine intramuscular vitamin K (phytonadione) to newborns at birth

Q19. Which anticoagulant directly inhibits factor IIa (thrombin)?

  • Rivaroxaban
  • Apixaban
  • Dabigatran
  • Enoxaparin

Correct Answer: Dabigatran

Q20. Which monitoring test is most affected by direct oral factor Xa inhibitors in routine practice?

  • INR is reliably prolonged and used for dosing adjustments
  • aPTT is the recommended routine monitor
  • Specific anti‑Xa assays calibrated for the drug provide best measurement
  • Bleeding time is used to monitor anticoagulant effect

Correct Answer: Specific anti‑Xa assays calibrated for the drug provide best measurement

Q21. Warfarin-induced skin necrosis is most closely associated with deficiency of which protein early in therapy?

  • Protein S (relative early deficiency)
  • Protein kinase C
  • Protein A
  • Antithrombin III

Correct Answer: Protein S (relative early deficiency)

Q22. Which statement about pharmacokinetics of vitamin K preparations is correct?

  • Oral phytonadione has faster onset than IV phytonadione
  • Intravenous phytonadione has a more rapid onset than oral forms
  • All vitamin K forms are ineffective for warfarin reversal
  • Menadione is exclusively administered intravenously in humans

Correct Answer: Intravenous phytonadione has a more rapid onset than oral forms

Q23. Heparin‑induced thrombocytopenia (HIT) is mediated by antibodies against which complex?

  • Platelet factor 4 (PF4)–heparin complex
  • Fibrinogen–thrombin complex
  • VKORC1–warfarin complex
  • Protein C–S complex

Correct Answer: Platelet factor 4 (PF4)–heparin complex

Q24. Which clinical advantage is associated with low molecular weight heparin versus unfractionated heparin?

  • Predictable dose response and reduced need for routine aPTT monitoring
  • Complete reversal with vitamin K
  • Lower bioavailability after subcutaneous injection
  • Higher risk of HIT in all patient populations

Correct Answer: Predictable dose response and reduced need for routine aPTT monitoring

Q25. Which of the following is a direct oral anticoagulant that targets factor Xa?

  • Dabigatran
  • Warfarin
  • Rivaroxaban
  • Heparin

Correct Answer: Rivaroxaban

Q26. In a patient with severe warfarin overanticoagulation but no major bleeding, the recommended management is often:

  • Immediate prothrombin complex concentrate for all cases
  • Oral vitamin K administration and temporary warfarin hold
  • Start therapeutic heparin infusion
  • Increase warfarin dose

Correct Answer: Oral vitamin K administration and temporary warfarin hold

Q27. Which drug interaction increases warfarin anticoagulant effect by inhibiting CYP metabolism?

  • Rifampin
  • Carbamazepine
  • Ampicillin
  • Metronidazole

Correct Answer: Metronidazole

Q28. Which feature distinguishes vitamin K‑dependent gamma‑carboxylation of clotting factors?

  • Calcium binding to Gla residues requires gamma‑carboxylation
  • It occurs in the cytosol without membrane involvement
  • It directly degrades fibrin clots
  • It is independent of dietary vitamin K

Correct Answer: Calcium binding to Gla residues requires gamma‑carboxylation

Q29. Which of the following is an appropriate anticoagulant choice for initial management of acute pulmonary embolism in pregnancy?

  • Warfarin throughout pregnancy
  • Low molecular weight heparin (LMWH)
  • Dabigatran as first choice
  • Direct oral factor Xa inhibitor in first trimester

Correct Answer: Low molecular weight heparin (LMWH)

Q30. Which monitoring parameter is most likely to remain unreliable in patients taking DOACs when assessed by routine coagulation tests?

  • Thrombin time to detect dabigatran reliably
  • INR to quantify anticoagulant intensity for rivaroxaban or apixaban
  • Specific anti‑Xa assay for apixaban when calibrated
  • Platelet count for HIT screening

Correct Answer: INR to quantify anticoagulant intensity for rivaroxaban or apixaban

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