MTM Anticoagulation Management 2 — Questions and Answers
Question 1: A patient on warfarin presents with an INR of 8.2 and no active bleeding. Which management approach is most appropriate?
- Hold warfarin and give vitamin K 10 mg IV
- Hold warfarin, give oral vitamin K 2.5 mg, and recheck INR in 24 hours (Correct answer)
- Continue warfarin at the same dose and recheck in 1 week
- Immediately administer 4-factor PCC
Correct answer: Hold warfarin, give oral vitamin K 2.5 mg, and recheck INR in 24 hours
For supratherapeutic INR >8 without bleeding, holding warfarin and giving low-dose oral vitamin K (2.5–5 mg) with close INR follow-up is standard management.
Question 2: Which direct oral anticoagulant (DOAC) requires dose adjustment based on a triple criterion of age, weight, and serum creatinine?
- Rivaroxaban
- Dabigatran
- Apixaban (Correct answer)
- Edoxaban
Correct answer: Apixaban
Apixaban uses a 'two-of-three' dose reduction criterion: age ≥80, weight ≤60 kg, or serum creatinine ≥1.5 mg/dL to reduce to 2.5 mg twice daily.
Question 3: A patient with mechanical mitral valve replacement asks about switching from warfarin to a DOAC. What is the appropriate recommendation?
- Apixaban is acceptable if INR is difficult to control
- DOACs are contraindicated in patients with mechanical heart valves (Correct answer)
- Dabigatran can be used if the patient has good renal function
- Rivaroxaban once daily is preferred over warfarin for this indication
Correct answer: DOACs are contraindicated in patients with mechanical heart valves
DOACs are contraindicated in patients with mechanical heart valves due to increased rates of thromboembolic events and bleeding demonstrated in the RE-ALIGN trial.
Question 4: A patient receiving therapeutic enoxaparin for DVT has a creatinine clearance of 18 mL/min. What adjustment is required?
- No adjustment needed; use same dose
- Reduce dose by 25%
- Switch to UFH infusion or reduce enoxaparin dose to 1 mg/kg once daily (Correct answer)
- Use fondaparinux instead
Correct answer: Switch to UFH infusion or reduce enoxaparin dose to 1 mg/kg once daily
Enoxaparin accumulates in severe renal impairment (CrCl <30 mL/min), requiring dose reduction to 1 mg/kg once daily or switching to UFH.
Question 5: Which reversal agent is specifically approved for reversing rivaroxaban and apixaban anticoagulation?
- Idarucizumab
- Protamine sulfate
- Andexanet alfa (Correct answer)
- Vitamin K
Correct answer: Andexanet alfa
Andexanet alfa is a recombinant factor Xa decoy approved for reversing rivaroxaban and apixaban in life-threatening or uncontrolled bleeding.
Question 6: A patient on warfarin for atrial fibrillation is starting fluconazole for a vaginal yeast infection. What action should be taken?
- No action needed; the interaction is not clinically significant
- Increase the warfarin dose prophylactically
- Decrease the warfarin dose by approximately 25–50% and monitor INR closely (Correct answer)
- Discontinue warfarin temporarily during fluconazole therapy
Correct answer: Decrease the warfarin dose by approximately 25–50% and monitor INR closely
Fluconazole is a strong CYP2C9 inhibitor that significantly increases warfarin levels, requiring a warfarin dose reduction and close INR monitoring.
Question 7: Which patient characteristic is used to calculate a patient's HAS-BLED score for bleeding risk assessment?
- Presence of diabetes mellitus
- Labile INR control (Correct answer)
- History of heart failure
- Presence of renal artery stenosis
Correct answer: Labile INR control
HAS-BLED includes Hypertension, Abnormal renal/liver function, Stroke history, Bleeding tendency, Labile INRs, Elderly (>65), and Drugs/alcohol.
MTM Anticoagulation Management 2
A patient on warfarin presents with an INR of 8.2 and no active bleeding.
Which management approach is most appropriate?