Vitamin K (Phytonadione)

Definition

Vitamin K (Phytonadione) is a fat-soluble vitamin that plays a crucial role in blood clotting by activating certain proteins required for coagulation. It is also used therapeutically to reverse the effects of anticoagulants like warfarin.

5 Must Know Facts For Your Next Test

1. Vitamin K is essential for the synthesis of clotting factors II, VII, IX, and X.
2. Phytonadione is the most common form of Vitamin K used to treat and prevent bleeding disorders.
3. Warfarin therapy can be counteracted by administering Vitamin K to restore normal clotting function.
4. Patients on prolonged antibiotic therapy may require Vitamin K supplementation due to disruption of gut flora that synthesize it.
5. Intravenous administration of Vitamin K should be done slowly to avoid potential anaphylactoid reactions.

Review Questions

• What role does Vitamin K play in blood clotting?
• How does Vitamin K interact with warfarin therapy?
• Why might patients on long-term antibiotics need Vitamin K supplementation?

Related terms

Warfarin: An oral anticoagulant that inhibits the synthesis of vitamin K-dependent clotting factors.

Anticoagulants: Medications that help prevent blood clots by inhibiting various factors in the coagulation process.

Prothrombin Time (PT): A test that measures how long it takes blood to clot and is often used to monitor patients on warfarin.