Which statement about warfarin therapy is incorrect?

Which statement about warfarin therapy is incorrect?

• A. You should take it at the same time each day
• B. Antibiotics can affect INR values
• C. A diet high in vitamin K must be avoided completely
• D. Vitamin K intake affects INR

Answer: (C)

Warfarin’s effect is tied to vitamin K and how consistently you eat and how drugs interact with you; the goal is to keep the INR in a stable therapeutic range. A diet that is high in vitamin K is not something to avoid completely—you don’t have to eliminate it, you just need to keep your intake steady. Large or abrupt changes in vitamin K intake can shift the INR, potentially requiring a dose adjustment. Taking warfarin at roughly the same time each day helps maintain a steady drug level and predictable anticoagulation. Antibiotics can affect INR values because they can alter gut bacteria that synthesize vitamin K and sometimes affect liver metabolism, changing how warfarin works. Vitamin K intake does influence INR, which is why consistency is key.

Warfarin’s effect is tied to vitamin K and how consistently you eat and how drugs interact with you; the goal is to keep the INR in a stable therapeutic range. A diet that is high in vitamin K is not something to avoid completely—you don’t have to eliminate it, you just need to keep your intake steady. Large or abrupt changes in vitamin K intake can shift the INR, potentially requiring a dose adjustment.

Taking warfarin at roughly the same time each day helps maintain a steady drug level and predictable anticoagulation. Antibiotics can affect INR values because they can alter gut bacteria that synthesize vitamin K and sometimes affect liver metabolism, changing how warfarin works. Vitamin K intake does influence INR, which is why consistency is key.