Safe Prescribing — MCQs

Question 241: A 68-year-old man with atrial fibrillation is admitted with acute confusion and headache. His INR is 8.2. He has no signs of bleeding. His regular medications include warfarin 5mg daily. What is the most appropriate immediate management?

• A. Administer oral vitamin K 1-3mg and withhold warfarin (Correct Answer)
• B. Administer intravenous vitamin K 10mg and withhold warfarin
• C. Administer prothrombin complex concentrate and vitamin K 5mg intravenously
• D. Withhold warfarin and recheck INR in 24 hours
• E. Give fresh frozen plasma 15ml/kg and withhold warfarin

Explanation: ***Administer oral vitamin K 1-3mg and withhold warfarin*** - For a patient with an **INR > 8.0** and **no evidence of bleeding**, international guidelines recommend withholding **warfarin** and administering **oral Vitamin K** to safely reduce the INR. - **Oral administration** is preferred in non-bleeding patients as it effectively lowers INR within 24 hours without the **anaphylaxis risk** associated with IV forms. *Administer intravenous vitamin K 10mg and withhold warfarin* - **Intravenous Vitamin K** at this dose (10mg) is reserved for **major or life-threatening hemorrhage** where rapid reversal is critical. - This patient has **no signs of bleeding**, and such a high IV dose may cause prolonged **warfarin resistance** if anticoagulation needs to be restarted. *Administer prothrombin complex concentrate and vitamin K 5mg intravenously* - **Prothrombin complex concentrate (PCC)** is indicated only for **emergency reversal** of warfarin in the presence of severe, **life-threatening bleeding**. - Since this patient has **no clinical signs of bleeding**, using clotting factor concentrates is unnecessary and carries a risk of **thrombosis**. *Withhold warfarin and recheck INR in 24 hours* - Simply **withholding warfarin** is only appropriate if the INR is between 5.0 and 8.0 with no bleeding. - Because the INR is **exceeding 8.0**, the risk of spontaneous hemorrhage is significantly elevated, necessitating the addition of **Vitamin K** to accelerate INR reduction. *Give fresh frozen plasma 15ml/kg and withhold warfarin* - **Fresh frozen plasma (FFP)** is not recommended for routine warfarin reversal due to suboptimal factor replacement and the risk of **fluid overload** and **allergic reactions**. - It is generally only considered if **PCC is unavailable** and there is active, **major bleeding** occurring, which is not the case here.