antiplatelet
13 interactions related to antiplatelet
warfarin + dong quai
Dong quai (Angelica sinensis) contains coumarin-family compounds (ferulic acid, osthole) and has antiplatelet activity in laboratory studies. A published case report described a previously stable warfarin patient whose INR climbed well above her target range within weeks of adding dong quai, then returned to normal after she stopped it. The signal rests on a single human case plus animal data, so it is taken seriously but is not extensively documented.
warfarin + feverfew
Feverfew (Tanacetum parthenium) inhibits platelet aggregation in laboratory studies via its parthenolide sesquiterpene lactones, which creates a theoretical, additive bleeding concern alongside warfarin. The evidence is bench/in-vitro only: systematic reviews classify feverfew's anticoagulant signal as low-level laboratory evidence, and there are no published human case reports of bleeding when feverfew is combined with warfarin. The cautious, mechanism-based approach is to avoid concentrated feverfew supplements while on warfarin and to disclose use to the clinician managing anticoagulation.
aspirin + ginkgo
Ginkgo biloba can inhibit platelet-activating factor (PAF) and platelet aggregation, which may add to aspirin's irreversible inhibition of cyclooxygenase-1 and thromboxane A2. Observational data suggest a modest increase in minor bleeding events when the two are combined, and there are case reports of more serious bleeds in vulnerable patients, though a controlled trial found no measurable added effect on platelet function.
aspirin + fish oil
Omega-3 fatty acids in fish oil mildly reduce platelet aggregation, which in theory adds to aspirin's antiplatelet effect. In practice, clinical studies have not found a clinically significant increase in major bleeding when standard fish oil is combined with aspirin.
warfarin + ginger
Ginger has a mild antiplatelet effect that can add to warfarin's anticoagulant effect. Case reports describe a rise in INR after a person on stable warfarin started a daily ginger supplement, with the INR returning to range once the supplement was stopped. Ginger used in cooking and the occasional ginger tea is a food-level exposure and is generally considered safe.
warfarin + ginkgo
Warfarin and ginkgo act on clotting through different pathways, raising a plausible but not firmly proven bleeding concern.
warfarin + turmeric
Curcumin, the main active in turmeric, has antiplatelet activity that can add to warfarin's effect and raise bleeding risk. New Zealand's medicines regulator, Medsafe, issued an alert in 2018 after a patient stable on warfarin had their INR climb to a dangerously high level within weeks of starting a turmeric/curcumin product. A possible effect on the enzyme that clears warfarin has been seen only in animal and laboratory studies, not in people.
clopidogrel + ginkgo
Clopidogrel blocks the platelet P2Y12 ADP receptor, while ginkgo biloba inhibits platelet-activating factor through a separate pathway. A controlled healthy-volunteer study found no measurable added platelet inhibition, but case reports and an observational analysis link the combination to bleeding. The realistic concern is a modest, additive bleeding risk, most relevant in older patients and those also taking aspirin.
turmeric tea + warfarin
Curcumin, the main active compound in turmeric, has antiplatelet and anticoagulant activity in laboratory studies and may inhibit the liver enzymes that clear warfarin. Regulatory case reports describe stable warfarin patients whose INR rose into a dangerous, emergency range within weeks of starting a turmeric product. The published evidence is limited to a small number of case reports, but the bleeding signal is consistent enough to warrant caution.
clopidogrel + garlic
Clopidogrel blocks the platelet P2Y12 ADP receptor to prevent clots. Concentrated garlic supplements also have a mild antiplatelet effect through sulfur compounds such as allicin and ajoene. Taken together, the antiplatelet effects can add up and may modestly raise bleeding risk, especially before procedures. Culinary garlic in food amounts is not a meaningful concern.
alcohol + aspirin
Aspirin and alcohol both damage the gastric lining and impair clotting; used together they raise the risk of upper gastrointestinal bleeding, with risk rising as alcohol intake and aspirin use increase.
vitamin e + platelet function test
Higher-dose vitamin E (alpha-tocopherol) can inhibit platelet aggregation through a protein kinase C-dependent mechanism, prolonging bleeding times and producing abnormal results on platelet function tests such as the PFA-100, VerifyNow, and light transmission aggregometry. The effect is most pronounced alongside aspirin or other antiplatelet drugs and can complicate a workup for a suspected bleeding disorder.
warfarin + garlic
Concentrated garlic supplements may add to warfarin's blood-thinning effect, mainly through a mild antiplatelet action, though the clinical evidence for important bleeding is weak.