Pharmacy Clinical Pearl of the Day: Warfarin and Vitamin K

Clinical Pearl of the Day: Warfarin and Vitamin K

• Warfarin (Coumadin) treats blood clots, such as those in deep vein thrombosis and pulmonary embolism.
• When taken, patients’ international normalized ratio (INR) test should be monitored on a regular basis.
• Vitamin K works against warfarin and can be used as an antagonist for it.

Explanation

• Vitamin K blocks the warfarin effects and thus causing lower INRs.
• The lower the INR, the less time it takes for the blood to clot.
• A low INR means the warfarin dose is not working well enough to prevent dangerous blood clots.
• Vitamin K, can be prescribed in various dosage forms, such as oral, to help stop the affect of warfarin, if needed
• Foods that contain too much vitamin K should be avoided when taking warfarin, which include green leafy vegetables.

Reference

Warfarin (Oral Route) Description and Brand Names - Mayo Clinic

Warfarin diet: What foods should I avoid? - Mayo Clinic