Warfarin is the most common medication used in the United States for anticoagulant therapy. It is sold under the brand names Coumadin® and Jantoven. Certain proteins need to be circulating in the blood in order for it to be able to clot. The proteins are formed in the liver and the body needs vitamin K to be able to produce them. Warfarin is a vitamin K antagonist. Anticoagulant medications are commonly called “blood thinners”, but they do
Warfarin was developed in the 1950s from spoiled sweet clover
not actually thin the blood; they interfere with the ability to make a clot. Warfarin accomplishes this by interfering with vitamin K. It was developed as a drug in the 1950s from spoiled sweet clover. Scientists noticed that if cattle ate too much of it, they developed a tendency to bleed.
Warfarin is used to treat or prevent blood clots in veins or arteries, which can reduce the risk of stroke, heart attack, or other serious conditions. There are precautions that should be taken before using warfarin. Patients with bleeding disorder, a blood cell disorder, blood in the urine or stools, stomach bleeding, very high blood pressure, an infection of the lining of the heart (bacterial endocarditis), recent or upcoming surgery, or if you need a spinal tap or epidural. Warfarin should be taken the same time every day.
Warfarin increases the risk of bleeding, which can be severe or life-threatening. Frequent tests to measure blood-clotting time are needed for patients taking . Call your doctor or seek emergency medical attention if you have bleeding that will not stop, if you have blood in your urine, black or bloody stools, or if you cough up blood or vomit that looks like coffee grounds.
Patients with celiac sprue, diabetes, congestive heart failure, overactive thyroid, connective tissue disorders (autoimmune diseases like Marfans, Sjogren syndrome, scleroderma, rheumatoid arthritis, or lupus) or have had low blood platelets after receiving heparin should inform their doctor about the condition.
Warfarin side-effects:
Warfarin can cause unusual bleeding, or bleeding that will not stop. It can also cause bleeding on the inside of the body, such as in your stomach or intestines. A physician should be contacted at once if there is blood in the urine, black or bloody stools, or if there is blood after coughing or vomit that looks like coffee grounds.
Other possible side-effects include:
- Pain, swelling hot or cold feeling
- Abdominal pain or cramping
- Unusual blleding, including: blood in the urine, bleeding gums, nose bleeds, bloody stools, coughing up blood or increased menstrual bleeding
- Blurred vision
- Tingling or “pins and needles” sensation; burning or itching
- Chest discomfort or pain
- Confusion
- Difficulty breathing or swallowing
- Dizziness, or lightheadedness when getting up suddenly from a sitting or lying position
- Excessive or easy bruising
- Headaches
- Red, black or tarry stools
Rare side-effects:
- Arm, back or jaw pain
- Abdominal pain
- Tightness in the chest
- Skin discoloration (black or blue-green). including blue or purple toes. Possibly small red or purple spots on the skin
- Clay-colored stools
- Diarrhea
- Fast or irregular breathing, or heart rate (trouble breathing with exertion)
- Fever
- Bloating or passing gass
- Bad taste in the mouth
- Loss or thinning of the hair
- Hives or welts
