Pharmacy Clinical Pearl of the Day: Warfarin and Vitamin K

Vitamin K works against warfarin and can be used as an antagonist for it.

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