warfarin (Coumadin, Jantoven)

  • Medical Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical Editor: Jay W. Marks, MD
    Jay W. Marks, MD

    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

GENERIC NAME: warfarin

BRAND NAME: Coumadin, Jantoven




  • Warfarin is used in treating patients with deep vein thrombosis (DVT) to prevent extension of the clot, and to reduce the risk of pulmonary embolism.
  • Patients with pulmonary embolism are treated with warfarin to prevent further emboli.
  • Warfarin also is used in patients with atrial fibrillation or artificial heart valves to reduce the risk of strokes, and after a heart attack.
  • It also is helpful in preventing blood clots from forming in certain orthopedic surgeries such as knee or hip replacements.
  • Warfarin is used in preventing closure of coronary artery stents due to clotting.


  • Warfarin causes cause major or fatal bleeding. Warfarin treatment should be monitored regularly using the INR test. Drugs, dietary changes, and other factors affect INR levels and warfarin therapy. Patients should be trained on how to reduce the risk of bleeding and to report signs and symptoms of bleeding.


The two most serious side effects of warfarin are:

  • Bleeding
  • Necrosis (gangrene) of the skin

Bleeding can occur in any organ or tissue. Bleeding around the brain can cause severe headache and paralysis. Bleeding in the joints can cause joint pain and swelling. Bleeding in the stomach or intestines can cause weakness, fainting spells, black tarry stools, vomiting of blood, or coffee ground material. Bleeding in the kidneys can cause back pain and blood in urine.

Other side effects include:

Signs of overdose include bleeding gums, bruising, nosebleeds, heavy menstrual bleeding, and prolonged bleeding from cuts.

Medically Reviewed by a Doctor on 8/5/2016

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