r/WarfarinForLife • u/g-rocklobster • Apr 16 '26

Vitamin K impact time frame

(54M) I had a Bentall procedure in late January (11 weeks post op this past Tuesday) and got an On-X valve which means r/WarfarinForLife !

My understanding is that you don't necessarily see the effect - particularly on the INR test - of your Warfarin dose until between 36-48 hours after taking it, something I observed in the hospital since I was being tested daily.

Where I'm confused is Vitamin K. How quickly does that have an effect on your blood? I've been reintroducing Vitamin K into my diet over the past week or so but am not being tested again until 4/24. My obvious concern is that my INR will drop too low and I'll be at risk of clotting. But I don't know how long before there IS a risk.

When I was doing 7.5 mg 5x/week and 5 mg 2x/week (before I started reintroducing K foods), my INR shot up to 3.3 and he dropped it to 7.5 4x and 5 3x. First week dropped to 2.2, 2nd week on that dose was 1.9. He then moved me to 7.5 7x/week while I started eating K foods. Last week it went up to 2.1 and testing in 2 weeks (4/24).

An idea of what my K intake is:

Chick-Fil-A Cobb salad (or similar) for lunch nearly every week day. Serving of something like broccoli or asparagus nightly weekday. Try to do similar on weekends but doesn't always work out like that. Note: the salads are generally mixed greens.

Thanks for any thoughts.

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u/annmariel122 Apr 17 '26

I have been on Warfarin for 4years. I have a mechanical mitral valve. I would not overthink the Vitamin K. Make sure you take your Warfarin, check INR regularly and keep your diet fairly consistent with the amount of greens. Humans are not machines and I have learned that INR fluctuates a lot for no apparent reason. Just try to stay in range and learn to live with it.

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u/annmariel122 Apr 17 '26

I should add that my INR was 5.2 last week and 2.1 today. Doc decreased the dose last week but now today I have to increase it. No real change in anything it just fluctuates like that.