A. Restart at a lower dose once the INR is in therapeutic range.
B. Give oral Vitamin K1.
C. Administer fresh frozen plasma.
D. Transfuse fresh blood.
Ans:B. Give oral Vitamin K1
Vitamin K1 is the specific antidote for warfarin
- It is an anticoagulant is commonly used to treat blood clots such as deep vein thrombosis and pulmonary embolism and to prevent stroke in people who have atrial fibrillation, valvular heart disease or artificial heart valves.
- Warfarin decreases blood clotting by blocking the enzyme vitamin K oxide reductase that reactivates vitamin K1.
- Without sufficient active vitamin K1, clotting factors II, VII, IX, and X have decreased clotting ability. The anticlotting protein C and protein S are also inhibited but to a lesser degree.
- The common side effect is bleeding.
- This risk increases greatly once the INR exceeds 4.5.
- It is recommended that the effects of warfarin typically be monitored by checking prothrombin time every one to four weeks.
- The effects of warfarin may be reversed with phytonadione (vitamin K1), fresh frozen plasma, or prothrombin complex concentrate.