⚠️ Mechanism
Green tea contains vitamin K which can antagonize warfarin. High consumption may reduce INR.
📋 Effect
Reduced anticoagulant effect at high consumption (>1/2 gallon/day)
💊 Management
Maintain consistent green tea intake. Avoid sudden changes in consumption.
Plain Language Summary
This combination is considered moderately risky. Consuming very large amounts of green tea can reduce the effectiveness of warfarin because green tea contains vitamin K.
Source
Taylor JR, Wilt VM. Pharmacotherapy 1999
Supporting Research
The effect of Green green tea consumption on body mass index, lipoprotein, liver enzymes, and liver cancer: An updated systemic review incorporating a meta-analysis
Green Tea Consumption and Risk of Breast Cancer and Recurrence-A Systematic Review and Meta-Analysis of Observational Studies
Green tea (Camellia sinensis) for the prevention of cancer
The Effect of Antioxidant Polyphenol Supplementation on Cardiometabolic Risk Factors: A Systematic Review and Meta-Analysis
Green tea consumption and risk of pancreatic cancer: a meta-analysis
Safety and Effectiveness of Oral Nutraceuticals for Treating Acne: A Systematic Review
Dietary Strategies for Weight Loss Maintenance
Green and black tea for the primary prevention of cardiovascular disease
Medical Disclaimer: This interaction record is for informational and educational purposes only and does not constitute medical advice. Drug-supplement interactions can be dangerous. Always consult your healthcare provider or pharmacist before combining any supplement with prescription medications. Do not stop or change any medication without professional guidance.