Anisindione MCQs With Answer provides B.Pharm students a focused review of anisindione, an oral anticoagulant and vitamin K antagonist. This concise, high-yield introduction covers pharmacology, mechanism of action (inhibition of vitamin K epoxide reductase), pharmacokinetics, therapeutic indications, dosing principles, adverse effects such as bleeding and skin necrosis, important drug–drug and drug–food interactions, monitoring by PT/INR, and reversal strategies with vitamin K, FFP, or PCC. Designed for exam preparation and clinical understanding, the questions emphasize critical concepts in anticoagulant therapy, patient counseling, and laboratory interpretation. Use this set to strengthen clinical reasoning and applied pharmacology skills. Now let’s test your knowledge with 30 MCQs on this topic.
Q1. Which enzyme is directly inhibited by anisindione leading to its anticoagulant effect?
- Gamma-glutamyl carboxylase
- Vitamin K epoxide reductase
- Thrombin (factor IIa)
- Factor Xa
Correct Answer: Vitamin K epoxide reductase
Q2. Anisindione reduces the activity of which coagulation factors?
- Factors II, V, VIII and XIII
- Factors II, VII, IX, X and proteins C and S
- Factors I, II, III and V
- Factors VII, VIII and von Willebrand factor
Correct Answer: Factors II, VII, IX, X and proteins C and S
Q3. Which laboratory test is the primary monitor for anisindione therapy?
- Activated partial thromboplastin time (aPTT)
- Bleeding time
- Prothrombin time with INR (PT/INR)
- Fibrinogen level
Correct Answer: Prothrombin time with INR (PT/INR)
Q4. Why is heparin bridging often required when initiating anisindione in acute thrombosis?
- Anisindione causes immediate fibrinolysis requiring heparin
- Initial reduction of proteins C and S can create a transient hypercoagulable state
- Anisindione antagonizes heparin unless used together
- Heparin neutralizes oral anticoagulant side effects
Correct Answer: Initial reduction of proteins C and S can create a transient hypercoagulable state
Q5. The first-line pharmacologic agent to reverse anisindione in non–life-threatening over-anticoagulation is:
- Protamine sulfate
- Vitamin K (phytonadione)
- Aminocaproic acid
- Recombinant factor VIIa
Correct Answer: Vitamin K (phytonadione)
Q6. Anisindione is contraindicated in pregnancy primarily because it can cause:
- Maternal hypertension
- Fetal teratogenic effects and bleeding (fetal warfarin syndrome)
- Excessive fetal growth
- Gestational diabetes
Correct Answer: Fetal teratogenic effects and bleeding (fetal warfarin syndrome)
Q7. The most common and clinically significant adverse effect of anisindione is:
- Nephrotoxicity
- Hepatotoxicity
- Bleeding
- Hypoglycemia
Correct Answer: Bleeding
Q8. Which coagulation parameter typically prolongs first after starting anisindione?
- aPTT due to intrinsic pathway factor depletion
- Bleeding time due to platelet dysfunction
- PT/INR due to early fall in factor VII
- Thrombin time
Correct Answer: PT/INR due to early fall in factor VII
Q9. Concomitant use of broad-spectrum antibiotics with anisindione commonly increases anticoagulant effect because antibiotics:
- Directly inhibit vitamin K epoxide reductase
- Increase production of clotting factors in the liver
- Reduce gut flora that synthesize vitamin K
- Enhance renal clearance of anisindione
Correct Answer: Reduce gut flora that synthesize vitamin K
Q10. The primary route of metabolism and elimination for anisindione is:
- Hepatic metabolism with renal excretion of metabolites
- Renal excretion of unchanged drug
- Exhalation via lungs
- Direct biliary elimination without metabolism
Correct Answer: Hepatic metabolism with renal excretion of metabolites
Q11. Which pharmacokinetic property of anisindione contributes to interactions with highly protein-bound drugs?
- Low oral bioavailability
- High hepatic clearance
- High plasma protein binding
- Rapid renal elimination
Correct Answer: High plasma protein binding
Q12. How long does it generally take for full anticoagulant effect of anisindione to manifest after starting therapy?
- Within 1–2 hours
- 6–12 hours
- 48–72 hours due to gradual depletion of vitamin K–dependent factors
- One week
Correct Answer: 48–72 hours due to gradual depletion of vitamin K–dependent factors
Q13. A major absolute contraindication to anisindione therapy is:
- Controlled hypertension
- Active major bleeding
- Well-controlled diabetes
- Age over 65 years
Correct Answer: Active major bleeding
Q14. Administration of vitamin K reverses anisindione by:
- Directly activating prothrombin
- Providing reduced vitamin K to allow carboxylation of clotting factors
- Binding circulating anisindione and inactivating it
- Stimulating platelet production
Correct Answer: Providing reduced vitamin K to allow carboxylation of clotting factors
Q15. Which of the following laboratory tests is less sensitive than PT/INR for monitoring anisindione?
- Prothrombin time (PT)
- International normalized ratio (INR)
- Activated partial thromboplastin time (aPTT)
- Factor VII activity assay
Correct Answer: Activated partial thromboplastin time (aPTT)
Q16. Frequent consumption of spinach and other green leafy vegetables during anisindione therapy will most likely:
- Increase anticoagulant effect
- Decrease anticoagulant effect due to higher vitamin K intake
- Have no effect on anticoagulation
- Cause immediate bleeding
Correct Answer: Decrease anticoagulant effect due to higher vitamin K intake
Q17. Anisindione belongs to which chemical class of oral anticoagulants?
- Coumarin derivatives
- Indandione derivatives
- Direct factor Xa inhibitors
- Direct thrombin inhibitors
Correct Answer: Indandione derivatives
Q18. For a patient with a mechanical heart valve, anisindione is used because it:
- Selectively inhibits platelet aggregation
- Provides reliable long-term oral anticoagulation to prevent valve thrombosis
- Has no bleeding risk
- Is safe in pregnancy
Correct Answer: Provides reliable long-term oral anticoagulation to prevent valve thrombosis
Q19. A B.Pharm student counseling a patient on perioperative management should know that for a high thrombotic-risk patient undergoing elective surgery, anisindione should generally be:
- Continued without interruption
- Stopped and bridged with short-acting heparin
- Replaced with aspirin only
- Switched to a NOAC on the day of surgery
Correct Answer: Stopped and bridged with short-acting heparin
Q20. Skin necrosis associated with anisindione therapy is most closely linked to which underlying condition?
- Acute renal failure
- Protein C deficiency leading to microthrombosis
- Hypersensitivity allergic reaction
- Excess vitamin K intake
Correct Answer: Protein C deficiency leading to microthrombosis
Q21. How frequently should INR be checked immediately after initiating anisindione before stabilization?
- Once every 3 months
- Daily until stable, then weekly to monthly
- Only at one month
- Never; clinical signs are sufficient
Correct Answer: Daily until stable, then weekly to monthly
Q22. Which dietary change would most likely potentiate the anticoagulant effect of anisindione?
- Increasing intake of green leafy vegetables
- Starting a prolonged course of broad-spectrum antibiotics
- Eating more citrus fruits
- Increasing dairy consumption
Correct Answer: Starting a prolonged course of broad-spectrum antibiotics
Q23. In a patient with life-threatening bleeding on anisindione, the fastest effective reversal is typically achieved with:
- Oral vitamin K alone
- Fresh frozen plasma (FFP) only
- Prothrombin complex concentrate (PCC) plus vitamin K
- Platelet transfusion
Correct Answer: Prothrombin complex concentrate (PCC) plus vitamin K
Q24. Which clotting factor, having the shortest half-life, falls first after starting anisindione?
- Factor II (prothrombin)
- Factor IX
- Factor VII
- Factor X
Correct Answer: Factor VII
Q25. The biochemical effect of anisindione on clotting factor synthesis is to prevent:
- Sulfation of tyrosine residues
- Gamma-carboxylation of glutamate residues required for calcium binding
- Glycosylation of proenzymes
- Proteolytic activation of zymogens
Correct Answer: Gamma-carboxylation of glutamate residues required for calcium binding
Q26. Compared with warfarin, anisindione’s major distinguishing feature is that it is:
- A direct thrombin inhibitor
- An indandione derivative rather than a coumarin derivative
- Excreted unchanged in urine
- Safe to use in pregnancy
Correct Answer: An indandione derivative rather than a coumarin derivative
Q27. Which commonly prescribed antiarrhythmic drug is known to increase the anticoagulant effect of anisindione by pharmacokinetic interaction?
- Metoprolol
- Amiodarone
- Digoxin
- Atenolol
Correct Answer: Amiodarone
Q28. Concurrent use of nonsteroidal anti-inflammatory drugs (NSAIDs) with anisindione increases bleeding risk primarily because NSAIDs:
- Induce hepatic metabolism of anisindione
- Enhance platelet dysfunction and can cause GI mucosal injury
- Directly activate clotting factors
- Increase vitamin K synthesis
Correct Answer: Enhance platelet dysfunction and can cause GI mucosal injury
Q29. Which of the following is a common therapeutic indication for anisindione?
- Treatment and prevention of deep venous thrombosis (DVT)
- Immediate thrombolysis of acute ischemic stroke
- Primary prevention of bacterial endocarditis
- Treatment of hyperlipidemia
Correct Answer: Treatment and prevention of deep venous thrombosis (DVT)
Q30. In the event of a recent large oral overdose of anisindione (within a few hours), the immediate gastrointestinal decontamination step is:
- Administering oral vitamin K only
- Activated charcoal if within a few hours of ingestion
- Wait for spontaneous recovery
- Immediate hemodialysis
Correct Answer: Activated charcoal if within a few hours of ingestion

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