Is Caffeine Safe with warfarin?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Avoid drastic changes in caffeine consumption (e.g., coffee, tea, energy drinks). Notify your doctor if you significantly increase or decrease intake. Monitor INR closely.
Why this interaction occurs
Caffeine is listed as a CYP1A2 inhibitor in the FDA label. Inhibition of CYP1A2 can increase exposure to the R-enantiomer of warfarin, potentially increasing INR and bleeding risk.
Evidence
Evidence level: strong.
Data source
FDA Drug Label (OpenFDA)
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 Caffeine interactions → · All warfarin interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.