supplement-interaction
3 interactions related to supplement-interaction
cayenne + warfarin
Capsaicin, the active constituent in cayenne (Capsicum), is theorized to add modestly to warfarin's blood-thinning effect through additive antiplatelet activity and possible effects on drug metabolism. The interaction is mechanistic; no human bleeding cases specific to cayenne plus warfarin have been documented, and interaction databases classify it as minor.
cinnamon + warfarin
Concentrated cassia cinnamon supplements are a major source of coumarin, a compound that can be hard on the liver and may interfere with how the body clears warfarin. Because warfarin has a very narrow safety margin, even small shifts can raise bleeding risk, and case reports describe elevated INR when cinnamon-containing products were added to stable warfarin therapy.
fenugreek + warfarin
Fenugreek (Trigonella foenum-graecum) contains coumarin-related compounds and has shown anticoagulant activity in laboratory studies. A published case report describes a rise in INR when a boldo-fenugreek combination product was added to stable warfarin therapy, with INR normalizing on discontinuation and rising again on rechallenge. The evidence is limited to that single case plus mechanistic plausibility, so the interaction is treated as plausible rather than firmly established.