Warfarin was discovered when Wisconsin farmers approached a chemist at the University of Wisconsin to find out why their cattle were sick. He found that a substance in the clover they were eating stopped their blood from clotting and caused them to bleed. This substance was named warfarin after the Wisconsin Alumni Research Foundation and was first used to kill rodents before seen as beneficial for humans. There are side effects, however, and some of them can be serious.
What is Warfarin Sodium?
Warfarin is an anticoagulant, which means it is a medication that stops the blood from coagulating or forming clots. There are substances called clotting factors II, VII, IX and X which are made in the liver and needed to form clots. These clotting factors, however, are not active unless changed to a certain form, as explained by Philip Majerus, M.D., Co-Chairman of the Division of Hematology at Washington University School of Medicine in "Goodman & Gilman's The Pharmacological Basis of Therapeutics." Warfarin interferes with this process and will not let them change to the active form.
Skin Necrosis
This side effect may be seen two to five days after people first start taking warfarin, according to Jeffrey Weitz, M.D., Director of the Henderson Research Centre in "Harrison's Principles of Internal Medicine." The term necrosis describes dead tissue, and people with this disorder develop red areas on their toes, buttocks, thighs or breasts. They have blood clots in the blood vessels on the outer edge of the red areas and dead tissue in the center. Scientists have determined that those with a skin necrosis caused by warfarin do not have enough of a protein named protein C or one named protein S.
Birth Defects
Warfarin in the bloodstream of a pregnant woman, crosses the placenta and enters the bloodstream of the developing fetus. It causes birth defects and can even cause the loss of the baby, states Dr. Majerus in "Goodman & Gilman's The Pharmacological Basis of Therapeutics." The bones of the fetus will not properly develop if the mother takes warfarin in her first trimester. If she takes it in the second or third trimester, the brain and spinal cord will be abnormal. Warfarin can also cause hemorrhages in the fetus or newborn.
Bleeding
In "Harrison's Principles of Internal Medicine," Dr. Weitz writes that warfarin can cause bleeding. It can be a mild nosebleed or people may see blood in their urine. Some people can even develop severe bleeding in their back, stomach or intestines. Bleeding in the brain, which can happen, is a life-threatening condition. Thus, to decrease the risk of any bleeding, the physician will closely monitor on a regular basis how long it takes for someone taking warfarin to form a clot. The physician will also advise which medications can have an effect on warfarin, making it more or less effective.
References
- "Goodman & Gilman's The Pharmacological Basis of Therapeutics"; Laurence Brunton, Ph.D.; 2006
- "Harrison's Principles of Internal Medicine"; Anthony Fauci, M.D., Dennis Kasper, M.D., Dan Longo, M.D. et al.; 2008
- University of Maryland Medical Center: Taking warfarin (Coumadin)
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