Is Melatonin Safe with Warfarin?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Use melatonin cautiously if you are on warfarin. Monitor INR more frequently when initiating or discontinuing melatonin. Report any signs of bleeding such as blood in urine or stool, prolonged bleeding from cuts, or unusual bruising.
Why this interaction occurs
Melatonin has demonstrated antiplatelet properties and may inhibit thromboxane synthesis. Case reports and pharmacodynamic studies suggest melatonin can potentiate the anticoagulant effect of warfarin, possibly through CYP1A2 inhibition affecting warfarin clearance.
Evidence
Evidence level: moderate.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 134,328 reports mentioning Warfarin. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Warfarin + supplement combination on this page.
FAERS reports are voluntary and cannot prove that a drug caused an event. Do not use report counts to assess the safety of this specific drug-supplement pair.
Frequently asked questions
Related interactions
All Melatonin interactions → · All Warfarin interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.