Supplements and Acenocoumarol.
Acenocoumarol, sold under the brand name Sinthrome, is a vitamin-K antagonist anticoagulant. It sits in a narrow therapeutic window monitored by INR.
Acenocoumarol is a vitamin K antagonist anticoagulant. The class is gradually being replaced by DOACs (apixaban, rivaroxaban, edoxaban) for atrial fibrillation, but remains in active UK prescribing for mechanical heart valves, antiphospholipid syndrome, and where DOAC contraindications apply. The defining feature is the narrow therapeutic window. INR is measured regularly because under-treatment leaves stroke risk on the table, while excess anticoagulation drives bleeding. The supplement surface is one of the largest in clinical pharmacology. Vitamin K opposes the drug directly. Most of the rest of the signal is additive antiplatelet or anticoagulant effect rather than a change in drug levels, which is where garlic, ginkgo and high-dose fish oil sit. Curcumin sits there too, with a weak CYP2C9 effect on top. CYP induction by St John's Wort drops INR. That combination is hard excluded. Any supplement decision belongs with the anticoagulant clinic.
Below are the 23 documented pairs we have explicitly assessed against Acenocoumarol in the Distil database: 2 red and 21 amber. The pairs cluster around 5 mechanisms: CYP induction, Vitamin K pathway, Additive anticoagulation, Reduced anticoagulant effect, and Additive antiplatelet effect. Every call is cited to either a clinical reference (PMID) or the British National Formulary. Anything not on this list is either still to be assessed or beyond our database scope. The checker beneath surfaces assessments by supplement, and the missing-item form at the bottom of the page routes any uncatalogued supplement into our next curation pass.
Documented interactions
Last reviewed 15 June 2026. Each interaction below is assessed against PubMed-indexed evidence.
CYP induction
Red Does St John's Wort interact with ?
St John's Wort speeds up how the body clears acenocoumarol, which can make the blood thinner much less effective and dangerously raise the risk of a clot. This is a serious interaction. Do not take St John's Wort with acenocoumarol, and if you already take both, tell your anticoagulant clinic before stopping either.
Evidence: Supported by human study data.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Panax Ginseng interact with ?
Panax ginseng has been reported to reduce the effect of vitamin-K-based blood thinners like acenocoumarol, which could lower your INR and reduce protection against clots. If you take acenocoumarol, discuss ginseng with your anticoagulant clinic and keep your INR monitored rather than starting it on your own.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Vitamin K pathway
Red Does Vitamin K2 interact with ?
Vitamin K2 directly opposes acenocoumarol, which is a blood thinner that works by blocking vitamin K. Taking K2 can make acenocoumarol less effective and raise the risk of a clot, and changing your K2 intake can swing your INR test result. If you take acenocoumarol, do not start or stop vitamin K2 without your anticoagulant clinic's guidance, and keep your intake steady.
Evidence: Supported by human study data.
Amber Does Coenzyme Q10 interact with ?
Coenzyme Q10 is structurally similar to vitamin K and may slightly reduce the effect of acenocoumarol, a vitamin-K-based blood thinner, which could lower your INR. The signal is weak and comes from reports with the related drug warfarin. If you take acenocoumarol, keep your CoQ10 intake steady and mention it to your anticoagulant clinic so your INR can be watched.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Green Tea Extract interact with ?
Green tea contains vitamin K, which can work against acenocoumarol, a vitamin-K-based blood thinner, and changing how much you drink can swing your INR. Large or fluctuating intakes are the concern. If you take acenocoumarol, keep green tea intake steady and tell your anticoagulant clinic.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Additive anticoagulation
Amber Does Andrographis interact with ?
Andrographis may raise the effect of acenocoumarol, both by a mild blood-thinning action of its own and by slowing how the body clears the drug. The direct evidence is from animal studies with a similar anticoagulant rather than from people taking acenocoumarol. If you take acenocoumarol, tell your anticoagulation clinic before starting andrographis and ask for an INR check a couple of weeks in.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Bromelain interact with ?
Bromelain has a mild blood-thinning effect that may add to acenocoumarol's. If you take acenocoumarol, tell whoever monitors your INR before adding bromelain and check your INR if you do. If you have surgery planned, mention bromelain to your team; stopping high-dose bromelain about two weeks beforehand is a common precaution.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Cordyceps interact with ?
Cordyceps may add to acenocoumarol's blood-thinning effect through a mild anti-clotting action of its own. This is based on laboratory work on human platelets rather than studies in people taking acenocoumarol, so the real-world size of the effect is unknown. If you take acenocoumarol, mention cordyceps to your anticoagulation clinic and ask whether an INR check is worth doing after you start.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Cranberry Extract (PAC-standardised) interact with ?
Cranberry, mainly as large volumes of juice, can occasionally raise the effect of acenocoumarol, a vitamin-K-based blood thinner in the same family as warfarin, and push your INR up. The signal comes from the related drug warfarin rather than from acenocoumarol directly. If you take acenocoumarol, keep your cranberry intake steady rather than starting or stopping it suddenly, and tell your anticoagulant clinic so your INR can be watched.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Curcumin interact with ?
Curcumin (from turmeric) can mildly reduce clotting, which may add to the blood-thinning effect of acenocoumarol. Cooking amounts of turmeric are not the concern; concentrated curcumin supplements are. If you take acenocoumarol, discuss curcumin with your anticoagulant clinic and watch for bruising or bleeding.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Fisetin interact with ?
Fisetin may mildly thin the blood by reducing platelet clumping, which could add to vitamin-K-based blood thinners like acenocoumarol. The concern is with a high-dose fisetin course, not food amounts. If you take acenocoumarol, tell your anticoagulant clinic before starting a fisetin course and watch for bruising or bleeding.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Glucosamine interact with ?
Glucosamine (often with chondroitin) has been reported to increase the blood-thinning effect of acenocoumarol and raise the INR, sometimes enough to cause bleeding. If you take acenocoumarol, it is best to avoid glucosamine or only use it with your anticoagulant clinic's knowledge and extra INR checks.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does L-Carnitine interact with ?
L-carnitine has been reported in a few cases to increase the effect of vitamin-K-based blood thinners like acenocoumarol, raising the INR. The evidence is limited. If you take acenocoumarol and use L-carnitine, mention it to your anticoagulant clinic and have your INR checked.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Pine Bark Extract interact with ?
Pine bark extract (pycnogenol) has a mild blood-thinning effect of its own, shown in people as reduced platelet stickiness, mainly in smokers. It has not been studied alongside acenocoumarol, so the size of any combined effect is unknown. If you take acenocoumarol, tell your anticoagulation clinic before starting pine bark extract and ask for an INR check a couple of weeks in.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Quercetin interact with ?
High-dose quercetin may mildly add to the blood-thinning effect of acenocoumarol. The signal is weak. If you take acenocoumarol and use quercetin supplements, mention it to your anticoagulant clinic and watch for bruising.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Resveratrol interact with ?
Resveratrol can both slow how the body clears vitamin-K-based blood thinners like acenocoumarol and mildly thin the blood by reducing platelet clumping, which could push your INR up. Food amounts are not the concern; concentrated supplements are. If you take acenocoumarol, tell your anticoagulant clinic before starting resveratrol and watch for bruising or bleeding.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Spirulina interact with ?
Spirulina has a mild antiplatelet signal in laboratory studies, but a human trial at a high dose found no change in clotting tests or platelet activity. Any effect on acenocoumarol is likely to be small. If you take acenocoumarol, keep your spirulina intake steady rather than starting or stopping suddenly, and tell your anticoagulation clinic what you take.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Reduced anticoagulant effect
Amber Does Collagen Precursors interact with ?
The 1,000 mg of vitamin C in this collagen precursor blend (a high daily dose) may reduce the effect of vitamin-K-based blood thinners like acenocoumarol, which could lower your INR; very high doses of vitamin C have been linked to this in rare reports. If you take acenocoumarol, keep this blend steady and mention it to your anticoagulant clinic.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Vitamin C interact with ?
Very high doses of vitamin C have been linked in rare reports to a reduced effect of vitamin-K-based blood thinners like acenocoumarol, which could lower your INR. Normal vitamin C intake is not a concern. If you take acenocoumarol and use high-dose vitamin C, keep it steady and mention it to your anticoagulant clinic.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Additive antiplatelet effect
Amber Does Garlic Extract interact with ?
Garlic supplements can thin the blood by reducing how well platelets clump, which adds to the blood-thinning effect of acenocoumarol and may raise bleeding risk. Culinary amounts of garlic are not the concern; concentrated extracts are. If you take acenocoumarol, discuss garlic supplements with your anticoagulant clinic and watch for easy bruising or bleeding.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Ginkgo Biloba interact with ?
Ginkgo can reduce platelet stickiness, which adds to the blood-thinning effect of acenocoumarol and may raise the risk of bleeding. If you take acenocoumarol, discuss ginkgo with your anticoagulant clinic and watch for unusual bruising or bleeding.
Evidence: Limited human data, based on case reports and a known mechanism.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Omega-3 EPA interact with ?
High-dose fish oil (omega-3) can mildly reduce platelet stickiness, which may add to the blood-thinning effect of acenocoumarol. The effect is usually small at typical doses. If you take acenocoumarol and use high-dose omega-3, mention it to your anticoagulant clinic and watch for easy bruising.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
Amber Does Vitamin E interact with ?
High-dose vitamin E can mildly reduce blood clotting, which may add to the blood-thinning effect of acenocoumarol and raise bleeding risk. The concern is with high supplemental doses. If you take acenocoumarol, keep vitamin E intake modest and tell your anticoagulant clinic.
Evidence: Based on an established mechanism, with no direct study of this exact combination yet.
Reviewer-flagged: awaiting clinical-reviewer sign-off.
What this list does not say. Pairs not flagged here are not implicitly safe. They are either not yet in our database, or fall outside our inclusion scope (food-supplement interactions only; for drug-drug interactions, the BNF is authoritative). Use the checker below to surface any supplement, and submit a missing item if you take something we have not catalogued.
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