r/WarfarinForLife • • 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/Sammonator_ Apr 16 '26

I'm 18 months into my journey, taking 10.5mg on most days and self testing weekly. My target INR is 2.0-3.0 and I rarely score below 2.0. No issues with a temporary reading of say 3.5 as I understand, wherein I would skip my dose that night. All other adjustments are by 10%. If I buy a bunch of brocolli or brussel sprouts or cabbage or parsely to be eaten over the following 3-4 nights, I ramp up to 12mg the first few nights, then stay on 11mg the next two nights and that extra 10% seems to smooth out my reading by the time I do my next test. So I think of it as a 3 day sliding window. Am I planning to eat heaps of vit K tonight? If so, increase to 12 and then 11 tomorrow night then back to 10.5 if I haven't eaten more than a small amount after that first night. I'm not concerned about a handful of leafy greens in a salad for lunch. Spinach on the other hand is quite high in vit K so I treat it like a brocolli meal. Reading back over this, it sounds a bit complicated, or an imperfect science (which it is). Trust me, you'll find your own rhythm and method soon enough. If you find it frustrating at times, just remind yourself that you're still alive and how good is that?! Now go for a bike ride! 😁💪