Warfarin
Life-saving with tradeoffs. Warfarin (Coumadin) prevents blood clots by blocking vitamin K recycling. But vitamin K does more than clot blood—it protects bones and arteries. Managing warfarin requires understanding these tradeoffs and maintaining consistent vitamin K intake.
How Warfarin Works
Blocks Vitamin K Recycling
VKORC1 enzyme inhibited. Vitamin K can't be reused. Clotting factors reduced.
Reduces Clotting Factors
Factors II, VII, IX, X need vitamin K. Less K = less clotting ability.
Prevents Blood Clots
Reduces stroke risk in afib. Prevents DVT, PE. Life-saving when needed.
The Vitamin K Balance
Don't Eliminate Vitamin K
Old advice was avoid it. New understanding: keep intake CONSISTENT, not zero.
Consistency Is Key
Same amount daily. Dose adjusted to YOUR intake. Don't fluctuate.
K2 Matters Too
Warfarin blocks K2 as well. Calcification risk increases. Arterial stiffening.
Bone Health Impact
K2 needed for bone health. Long-term warfarin increases fracture risk.
High K Foods
Leafy greens, broccoli, Brussels sprouts. Don't avoid—just be consistent.
Supplement Caution
Many supplements affect INR. Always inform doctor. Fish oil, garlic, ginkgo...
Important Interactions
Antibiotics
Many increase warfarin effect. Extra monitoring needed. Inform prescriber.
NSAIDs
Ibuprofen, aspirin increase bleeding risk. Avoid or use carefully.
Fish Oil
May increase bleeding. Monitor if using. Lower doses often fine.
Alcohol
Affects liver metabolism. Inconsistent drinking problematic. Moderate consistently.
Cranberry
Can increase warfarin effect. Large amounts problematic. Juice and supplements.
Newer Alternatives (DOACs)
No Vitamin K Interaction
Apixaban, rivaroxaban, dabigatran don't block vitamin K. Diet more flexible.
Less Monitoring
No INR checks needed. Fixed dosing. More predictable.
Discuss With Doctor
Not appropriate for everyone. Mechanical valves still need warfarin. Cost higher.