How long does Vitamin K's effect last on the blood?

Duration of Vitamin K's Effect on Blood Coagulation

The maximum effect of intravenous vitamin K administration lasts approximately 6-12 hours, while oral vitamin K supplementation takes about 24 hours to reach maximum effect. 1

Route of Administration and Duration of Effect

• Intravenous (IV) vitamin K has a maximum effect lasting 6-12 hours, making it suitable for rapid correction of coagulopathy 1
• Oral vitamin K takes longer to work, with maximum effect occurring at approximately 24 hours after administration 1
• For patients requiring immediate reversal of vitamin K antagonists (VKAs), the missing coagulation factors (FII, FIX, FX) are typically replaced with prothrombin complex concentrate (PCC), as the half-life of administered FVII is only about six hours 1

Clinical Applications and Timing Considerations

• When administering PCC for VKA reversal, vitamin K1 (phytomenadione) should be co-administered to stimulate production of vitamin K-dependent coagulation factors after the initial effect of PCC wears off 1
• For patients with mechanical valves and uncontrollable bleeding who have received 4-factor prothrombin concentrate complex, adjunctive use of intravenous vitamin K is reasonable if resumption of VKA therapy is not anticipated for 7 days 1
• After reversal with vitamin K, INR should be monitored regularly over the next week, as a minority of patients take over a week to clear warfarin from their blood and require additional vitamin K 1

Dosing Considerations

• For immediate reversal of anticoagulation in life-threatening bleeding, a 10-mg intravenous dose of vitamin K is recommended 1
• A 5–10 mg dose of vitamin K is generally recommended for VKA reversal, as lower doses may not fully correct the INR 1
• More than 10 mg of vitamin K1 can prevent re-warfarinisation for days and may create a prothrombotic state, which could lead to further thromboembolism 1

Special Considerations and Precautions

• Rare anaphylactoid reactions with bronchospasm and cardiac arrest can occur after IV vitamin K1 administration, with an incidence of 3 per 100,000 doses 1
• The use of PCC with vitamin K is associated with an increased risk of venous and arterial thrombosis during the recovery period 1
• Alterations in vitamin K intake can affect the response to anticoagulant agents, requiring careful monitoring of blood clotting tests in patients using anti-vitamin K drugs 1
• The threshold dose of vitamin K1 supplements causing a statistically significant lowering of the INR is approximately 150 μg/day when taken for 7 days 2

Pitfalls to Avoid

• Administering too much vitamin K (>10 mg) can create a prothrombotic state and prevent re-warfarinisation for days 1
• Using subcutaneous administration of vitamin K is not recommended as it does not modify coagulation parameters effectively 3
• Overreliance on INR as a predictor of bleeding risk in liver disease, as studies have shown poor correlation between INR values and bleeding events 3, 4
• Administering vitamin K to correct prolonged INR in patients with liver disease lacks supporting evidence, as it does not significantly improve INR in these patients 3