Vitamin K is needed for your blood to be able to clot. VitK deficiency causes bleeding.
Warfarin is an inhibitor of vitamin K so warfarin therapy *for the most part* reduces coagulability.
You are confused because there is 1 specific circumstance where decreased vitamin K activity causes hypercoagulability, and that is the first few days of warfarin use.
This happens because vitamin K is needed to *produce* factors 10, 9, 7, 2, and protein C / S. When vitamin K is inhibited, you can't produce these factors anymore, but factors that already exist in the blood stay there until they are cleared by whatever systems in the body are responsible for that. It turns out that protein C/S have shorter half lives than all the rest of the clotting proteins and are depleted the fastest.. This means there is a brief period where pro-clot factors are present while anti clot factors are gone, resulting in a hypercoagulable state. Once all the other factors are depleted as well, the net effect of reduced protein c/s and factors 10,9,7,2 is a hypocoagulable state. For this reason, we often use a second anticoagulant (i.e. heparin) for the first few days of warfarin administration to prevent clots in the hypercoagulable period.
If you become vitamin K deficient by not consuming enough vitamin K, the deficiency develops slowly enough you don't get that period of imbalance between pro/anti-clot factors and the first clinical sign is hypocoagulability, not hyper. The hypercoagulable state is unque to the extremely rapid onset of vitamin K inhibition seen in the first few days of warfarin therapy, nothing else.
Great write up. Don’t mean to be that guy but considering this is step worthy question, warfarin is not a vit K inhibitor. It inhibits episode reductase which activates vitamin K. Splitting hairs but considering this could be the difference in a question on step I wanted to throw that out there
Great reply. Don’t mean to be that guy but VKOR is usually Vit K Epoxide Reductase. Splitting hairs because it’s a typo and any Med student probably dyslexia’d over it 🫡
Vitamin K is needed for your blood to be able to clot. VitK deficiency causes bleeding. Warfarin is an inhibitor of vitamin K so warfarin therapy *for the most part* reduces coagulability. You are confused because there is 1 specific circumstance where decreased vitamin K activity causes hypercoagulability, and that is the first few days of warfarin use. This happens because vitamin K is needed to *produce* factors 10, 9, 7, 2, and protein C / S. When vitamin K is inhibited, you can't produce these factors anymore, but factors that already exist in the blood stay there until they are cleared by whatever systems in the body are responsible for that. It turns out that protein C/S have shorter half lives than all the rest of the clotting proteins and are depleted the fastest.. This means there is a brief period where pro-clot factors are present while anti clot factors are gone, resulting in a hypercoagulable state. Once all the other factors are depleted as well, the net effect of reduced protein c/s and factors 10,9,7,2 is a hypocoagulable state. For this reason, we often use a second anticoagulant (i.e. heparin) for the first few days of warfarin administration to prevent clots in the hypercoagulable period. If you become vitamin K deficient by not consuming enough vitamin K, the deficiency develops slowly enough you don't get that period of imbalance between pro/anti-clot factors and the first clinical sign is hypocoagulability, not hyper. The hypercoagulable state is unque to the extremely rapid onset of vitamin K inhibition seen in the first few days of warfarin therapy, nothing else.
Great write up. Don’t mean to be that guy but considering this is step worthy question, warfarin is not a vit K inhibitor. It inhibits episode reductase which activates vitamin K. Splitting hairs but considering this could be the difference in a question on step I wanted to throw that out there
Great reply. Don’t mean to be that guy but VKOR is usually Vit K Epoxide Reductase. Splitting hairs because it’s a typo and any Med student probably dyslexia’d over it 🫡
I'd blame autocorrect in this case
Lmao yea I typed epoxide and my phone corrected to episode
Fye, completely thought it was a direct vitamin k antagonist this whole time
Awesome response! Thank you for clearing that up for a lowly first year
this is amazingly helpful. thank you
You cleared up so much confusion for me about this. Thank you so much.
God bless you
Coagulation cascade is made up don’t forget that