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Warfarin

Warfarin

Warfarin belongs to the class of medications called anticoagulants. It is sometimes referred to as a "blood thinner," although it does not actually thin the blood.

Available form

Tablet

Dosage

1mg, 2.5mg, 2mg, 3mg, 4mg, 5mg, 6mg, 7.5mg, 10mg

Manufacturers

Apotex, Sanis Health, Taro Pharmaceuticals, Teva

Branded drugs

Coumadin

Buy Warfarin Full drug details

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Warfarin information

Dosage

Side Effects

Available Form

Contraindications

Precautions

Warnings

Directions of use

The dose of warfarin is individualized by your doctor according to blood clotting time. Blood clotting time is determined by a laboratory test, called an INR, which should be performed at regular intervals. It is very important to keep your lab appointments, as there is a narrow range between too much and too little of the medication. Too much medication may cause you to bleed more. Too little medication may lead to harmful clots forming.

Different circumstances in your life (e.g., eating certain foods or using certain medications) can cause the medication to work more or less effectively. Ask your doctor or pharmacist for a list of these foods and medications.

It is important to manage your lifestyle and habits appropriately when taking warfarin:

do not make drastic changes in your diet, such as eating large amounts of green, leafy vegetables
do not attempt to change your weight by dieting without first checking with your doctor or pharmacist
do not participate in any activity or sport that may result in serious injury
avoid drinking alcohol
avoid drinking cranberry juice or consuming other products that contain cranberries
avoid cutting yourself

It is very important that you take warfarin exactly as prescribed by your doctor. Take your dose of warfarin at the same time each day. If you miss a dose of warfarin, notify your health care provider right away. Take the missed dose as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store Warfarin at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.

Many medications can cause side-effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes Warfarin. If you are concerned about side effects, discuss the risks and benefits of Warfarin with your doctor.

The following side effects have been reported by at least 1% of people taking Warfarin. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

changes in skin colour
Diarrhea
dizziness
fatigue
general feeling of being unwell
headache
nausea
weakness

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

heavier-than-normal menstrual bleeding
numbness or tingling of hands, feet, or face
rash or itching
signs of Anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don't stop bleeding)
signs of "purple toe syndrome" (e.g., changing, mottled colour of toes, pain and tenderness of toes, sores that don't heal)
signs of liver damage (i.e., yellowing of skin or eyes, dark urine, light-coloured stools)
signs of serious skin damage (e.g., sores, changed skin colour or temperature)
sudden shortness of breath
unusual pain or swelling

Stop taking the medication and seek immediate medical attention if any of the following occur:

fainting
signs of a serious allergic reaction (i.e., swelling of face or throat, Hives, or difficulty breathing)
signs of bleeding (dark, tarry stools, bleeding in eye, blood in stools, blood in vomit or vomit that looks like coffee grounds, blood in urine, coughing up blood)
signs of bleeding in the brain (e.g., sudden or severe headache; sudden loss of coordination; vision changes; sudden slurring of speech; or unexplained weakness, or numbness)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking Warfarin.

1 mg
Each pink, single-scored tablet, with "WARFARIN1" on one side and "TARO" on the other, contains 1 mg of warfarin sodium. Nonmedicinal ingredients: D&C Red No. 6 Lake, lactose, magnesium stearate, and pregelatinized cornstarch.

2 mg
Each lavender, single-scored tablet, with "WARFARIN2" on one side and "TARO" on the other, contains 2 mg of warfarin sodium. Nonmedicinal ingredients: FD&C Blue No. 2 Lake, FD&C Red No. 40 Lake, lactose, magnesium stearate, and pregelatinized cornstarch.

2.5 mg
Each green, single-scored tablet, with "WARFARIN2½" on one side and "TARO" on the other, contains 2.5 mg of warfarin sodium. Nonmedicinal ingredients: D&C Yellow No. 10 Lake, FD&C Blue No. 2 Lake, lactose, magnesium stearate, and pregelatinized cornstarch.

3 mg
Each tan, single-scored tablet, with "WARFARIN3" on one side and "TARO" on the other, contains 3 mg of warfarin sodium. Nonmedicinal ingredients: D&C Yellow No. 10 Lake, FD&C Blue No. 2 Lake, FD&C Red No. 40 Lake, lactose, magnesium stearate, and pregelatinized cornstarch.

4 mg
Each blue, single-scored tablet, with "WARFARIN4" on one side and "TARO" on the other, contains 4 mg of warfarin sodium. Nonmedicinal ingredients: FD&C Blue No. 1 Lake, lactose, magnesium stearate, and pregelatinized cornstarch.

5 mg
Each peach, single-scored tablet, with "WARFARIN5" on one side and "TARO" on the other, contains 5 mg of warfarin sodium. Nonmedicinal ingredients: D&C Red No. 6 Lake, D&C Yellow No. 10 Lake, lactose, magnesium stearate, and pregelatinized cornstarch.

6 mg
Each teal, single-scored tablet, with "WARFARIN6" on one side and "TARO" on the other, contains 6 mg of warfarin sodium. Nonmedicinal ingredients: FD&C Blue No. 2 Lake, FD&C Yellow No. 10 Lake, lactose, magnesium stearate, and pregelatinized cornstarch.

7.5 mg
Each yellow, single-scored tablet, with "WARFARIN7½" on one side and "TARO" on the other, contains 7.5 mg of warfarin sodium. Nonmedicinal ingredients: D&C Yellow No. 10 Lake, lactose, magnesium stearate, and pregelatinized cornstarch.

10 mg
Each white, single-scored tablet, with "WARFARIN10" on one side and "TARO" on the other, contains 10 mg of warfarin sodium. Nonmedicinal ingredients: lactose, magnesium stearate, and pregelatinized cornstarch. The 10 mg does not contain dye.

Before you begin using a medication, be sure to inform your doctor of any medication conditions or Allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use Warfarin.

Bleeding: The most serious risk associated with warfarin is bleeding in any tissue or organ. The risk of bleeding is related to how much is taken and for how long.

It is extremely important to have regular blood tests (as recommended by your doctor) to ensure that the correct level of blood thinning is occurring. These blood tests measure your INR level to determine the dose of warfarin. Your health care provider will adjust the dose of warfarin depending on the INR level to ensure you are not receiving too little medication (which may result in blood clots forming) or too much medication (which may result in bleeding).

Congestive heart failure: People with congestive heart failure may be more sensitive to the effects of warfarin. If you have any heart problems, discuss with your doctor how Warfarin may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Warfarin, and whether any special monitoring is needed.

Dental or surgical treatment: It may be necessary to stop taking warfarin briefly before scheduled dental or surgical procedures. Make sure that everyone involved in your health care is aware that you are taking Warfarin.

Liver function: Liver disease or reduced liver function may cause Warfarin to build up in the body, causing side effects, including severe bleeding. If you have liver problems, discuss with your doctor how Warfarin may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Warfarin, and whether any special monitoring is needed.

Medical conditions and other medications: If you have other medical conditions and are taking medications, discuss with your doctor how Warfarin may affect your medical condition, how your medical condition may affect the dosing and effectiveness of Warfarin, and whether any special monitoring is needed.

Some conditions and medications affect the way warfarin works and may affect the dosing of warfarin. Your doctor will recommend you get regular lab tests done.

Non-steroidal anti-inflammatory medications (NSAIDs): It is recommended that anyone taking NSAIDs such as acetylsalicylic acid (Asa) or Ibuprofen should be closely monitored to ensure that no change in anticoagulation dosage is required. NSAIDs can cause stomach ulcers or bleeding. If you notice any signs of bleeding, such as frequent nosebleeds, unexplained bruising, or black and tarry stools, notify your doctor as soon as possible.

Purple toes syndrome: Purple toes syndrome is a complication of warfarin treatment and consists of a dark, purplish or mottled colour of the toes, usually occurring 3 to 10 weeks (or later) after starting treatment with warfarin. Major features of this syndrome include:

increasing and decreasing of the colour over time
pain and tenderness of the toes
purple colour of bottom surfaces and sides of the toes that turns white under moderate pressure and fades with elevation of the legs

Inform your doctor at once if you notice these symptoms.

Pregnancy: Warfarin should not be used during pregnancy. It may pass to the developing fetus and cause birth defects or death as a result of bleeding. If you become pregnant while taking Warfarin, contact your doctor immediately.

Breast-feeding: It is not known if warfarin passes into breast milk. If you are a breast-feeding mother and are taking Warfarin, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.

Children: The safety and effectiveness of Warfarin have not been established for children less than 18 years of age. However, the use of warfarin by children is necessary in certain situations.

Warfarin belongs to the class of medications called anticoagulants. It is sometimes referred to as a "blood thinner," although it does not actually thin the blood.

Warfarin helps to prevent Blood Clots from forming or from getting bigger, but it does not dissolve blood clots. Warfarin is used for the treatment of blood clots in the veins, arteries, lungs, and heart. It is also used to prevent clots for people with conditions that put them at an increased risk of developing blood clots (e.g., some abnormal heart rhythms [atrial fibrillation], leg circulation problems, Heart Attack or Congestive Heart Failure). It is also used to reduce the risk of blood clots due to surgical procedures or trauma.

Blood clots in the circulation are dangerous because they can cause medical problems such as heart attacks, Stroke, and pulmonary Embolism. Warfarin helps to reduce blood clotting within 24 hours of taking the medication. The full effect may take 72 to 96 hours to occur.

Warfarin works by partially blocking the reuse of vitamin K in your liver. Vitamin K is needed to make clotting factors that help the blood to clot and prevent bleeding. Vitamin K is found naturally in foods such as leafy, green vegetables, and certain vegetable oils. If you are taking warfarin, you may continue to eat these foods, but do not make any drastic changes to your diet.

Warfarin may be available under multiple brand names and/or in several different forms. Any specific brand name of Warfarin may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of Warfarin may not be used for all of the conditions discussed here.

Your doctor may have suggested Warfarin for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking Warfarin, speak to your doctor. Do not stop taking Warfarin without consulting your doctor.

Do not give Warfarin to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take Warfarin if their doctor has not prescribed it.

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All material © 1996-2025 MediResource Inc. Terms and conditions of use. The contents herein are for informational purposes only. Always seek the advice of your physician or other qualified health providers with any questions you may have regarding a medical condition.

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