coumadin
13 interactions related to coumadin
parsley + warfarin
Fresh parsley is extraordinarily dense in vitamin K1 - about 1,640 mcg per 100 grams, or roughly 62 mcg per tablespoon - so although typical garnish-sized servings are small, large culinary uses (tabbouleh, chimichurri, parsley smoothies, juicing) can deliver enough vitamin K to oppose warfarin and lower the INR.
matcha + warfarin
Matcha is powdered whole green tea leaf, so each serving delivers far more vitamin K than a normal brewed cup. Vitamin K is the cofactor warfarin antagonises, so large or fluctuating matcha intake can lower INR and reduce the anticoagulant effect, similar to the documented green tea-warfarin case report.
cranberry + warfarin
Cranberry juice contains flavonoids that may inhibit CYP2C9, the primary enzyme that metabolizes the active S-enantiomer of warfarin. Multiple case reports describe elevated INR and major bleeding (including fatal hemorrhage) in patients who drank cranberry juice while stably anticoagulated, though randomized trials with smaller doses have not consistently reproduced the effect.
green tea + warfarin
Green tea leaves contain vitamin K, which is a cofactor for hepatic synthesis of the clotting factors that warfarin inhibits. Large or fluctuating intake of green tea can lower INR and reduce the anticoagulant effect of warfarin, as documented in a published case report.
collard greens + warfarin
Collard greens are one of the highest-vitamin-K vegetables available, with roughly 836 mcg of vitamin K1 per cup cooked - more than seven times the daily adequate intake for adults. Sudden increases or decreases in consumption directly antagonize warfarin and can push the INR out of its therapeutic range.
spinach + warfarin
Spinach is one of the highest dietary sources of vitamin K1 (phylloquinone), with roughly 145 mcg per cup raw and 889 mcg per cup cooked. Because warfarin works by blocking vitamin K-dependent clotting factor synthesis, large or fluctuating spinach intake antagonizes warfarin and can drop the INR into a sub-therapeutic range, raising clot risk.
turnip greens + warfarin
Turnip greens contain about 529 mcg of vitamin K1 per cup cooked - roughly five times the daily adequate intake. Because warfarin works by blocking vitamin K-dependent clotting factor synthesis, large or fluctuating servings can drop the INR into a sub-therapeutic range and raise clot risk.
romaine + warfarin
Romaine lettuce contains roughly 48 to 60 mcg of vitamin K1 per cup shredded - lower than dark cooking greens but still meaningful at multi-cup salad servings. Large daily salads or romaine-heavy juices can supply enough phylloquinone to oppose warfarin and drift the INR downward.
microgreens + warfarin
Microgreens - the immature seedlings of vegetables and herbs harvested 7 to 21 days after germination - concentrate nutrients on a per-gram basis. Phylloquinone content varies widely by species, from roughly 0.6 to 4.1 mcg per gram, with brassica and amaranth microgreens highest. Daily handfuls or smoothie additions can supply enough vitamin K to oppose warfarin and shift the INR.
pomegranate + warfarin
Pomegranate juice contains punicalagins and other polyphenols that inhibit CYP2C9 and CYP3A4 in vitro, which would slow warfarin metabolism. Case reports describe both elevated INR (one patient reached INR 14 after heavy consumption) and subtherapeutic INR after stopping habitual juice intake.
acai + warfarin
Acai berries contain polyphenols, salicylate-like compounds, and unsaturated fatty acids that may have mild antiplatelet activity, but there are no published case reports of clinically significant INR changes. The theoretical concern is additive bleeding risk at high doses or with concentrated extracts, not enzymatic CYP interference.
swiss chard + warfarin
Swiss chard delivers approximately 299 mcg of vitamin K1 per cup raw and over 570 mcg per cup cooked - several times the adult adequate intake. As a direct vitamin K antagonist, warfarin's effect is reduced when dietary phylloquinone rises, so sudden increases in swiss chard intake can lower the INR into a sub-therapeutic, clot-prone range.
mustard greens + warfarin
Mustard greens are a dark leafy green packed with vitamin K1, providing roughly 419 mcg per cup cooked - several times the adult daily adequate intake. Because warfarin works by blocking vitamin K-dependent clotting factor synthesis, large or fluctuating intake can lower the INR and reduce clot protection.