Pharm 101: Vitamin K
Class
Vitamin
Pharmacodynamics
- Confers biologic activity upon factors II (prothrombin), VII, IX and X by participating in their postribosomal modification
- Two forms:
- Vitamin K1 is found in food, primarily green leafy vegetables
- Vitamin K2 synthesised by intestinal bacteria
- Clinical uses:
- Reversal of warfarin anticoagulation, prevention of haemorrhagic disease of new born
- IV or PO Vitamin K1 is available clinically
- IV administration should be slow as rapid infusion can cause dyspnoea, chest and back pain, and death
Reversal of warfarin anticoagulation
- Warfarin prevents reductive metabolism of inactive vitamin K to active form so produces biologically inactive VII, IX, X, prothrombin, protein C and S
- Vitamin K confers biologic activity upon factors II, VII, IX, X by participating in their postribosomal modification
- Re-establishes normal activity of vitamin K dependent clotting factors II, VII, IX, X
- 6-24 hours for effect
Further reading
- Buttner R. Pharm 101: Warfarin. LITFL
References
- Katzung BG. Basic and Clinical Pharmacology. 14e. 2018: 620-621
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Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Co-creator of the LITFL ECG Library. Twitter: @rob_buttner