HealthyCanada.com

Your body has a number of tools available to protect itself from injury. One of them is the ability to form a blood clot to stop a cut from bleeding. This process is called coagulation. Protein in your blood joins forces with platelets to form a thickened mass that acts as a dam preventing dangerous blood loss.

Sometimes however your blood clots when it is simply going about its business traveling through the veins and arteries to your heart and brain. This usually occurs in the legs or pelvic area where blood moves more slowly. This can be very dangerous as a clot can break loose and travel through the bloodstream to the lungs where it can cause a pulmonary embolism or to the brain where it can cause a stroke.

Warfarin is an anticoagulant. It works by stopping the formation of substances that cause clots ensuring that they don't form or at least don't grow any larger. It is often prescribed for patients who are at a higher risk for clots. Examples include those with certain types of irregular heartbeat such as atrial fibrillation or after a heart attack or heart valve replacement surgery. Warfarin is also used with other drugs in the treatment of some lung cancers.

The amount of warfarin prescribed depends on the results of a blood test called an "INR" that checks whether your blood is too thin or thick. This means you have to take a blood test especially when you first start to take this medication.

It is important to disclose your medical history including any pre-existing conditions. You should not take this drug if you are allergic to warfarin aspirin or tartrazine (yellow food colouring that is also used in some drugs). Also tell your doctor if you have had your prostate removed or have or have ever had:

• a stroke
• kidney disease
• liver disease
• high blood pressure
• a thyroid condition
• diabetes
• tuberculosis
• a bleeding disorder
• ulcers
• leukemia
• vitamin C deficiency
• a colostomy bag
• intestinal disease

Tell your doctor of any and all side effects that you experience while taking this drug including:

• bleeding from your gums after brushing your teeth
• nosebleeds
• headache
• upset stomach
• cramping
• fever
• diarrhea
• fever
• skin rash

Contact your doctor immediately if you have any of these more serious side effects:

• unusual bleeding or bruising
• black or bloody stools
• blood in the urine
• tiredness
• unexplained fever
• chills
• sore throat
• stomach pain

When you take warfarin you may notice that your urine changes colour (reddish orange). This is a temporary and harmless side effect.

Anticoagulants may cause other side effects. Talk to your doctor if you have any unusual symptoms while taking this medicine.

Always provide your doctor with a list of all other drugs you are taking (including over-the-counter medications) as they may interact with another drug increasing or decreasing effectiveness and safety of either or both. Tell your doctor specifically if you are taking any drugs for:

• cancer
• depression
• diabetes
• digestive problems
• epilepsy
• gout
• high cholesterol
• thyroid problems
• other heart medications
• antibiotics
• aspirin and other non-steroidal anti-inflammatory drugs

If you are using or plan to use any vitamin supplements or herbal products talk to your doctor first.

Remember how your body forms clots to stop bleeding when you are injured? Well if you are taking warfarin it's going to slow down that process so you'll have to be very careful not to get cut or to have bad falls. It will now take longer for the bleeding to stop and bruising will likely be worse.

If you are scheduled for surgery tell your healthcare providers that you are taking warfarin. Dentists need to know as well. Depending on the dental work you may have to stop taking it for a few days before your appointment. If you have an illness that causes vomiting diarrhea or fever for more than a few days call your doctor.

Seniors may take this drug as prescribed.

Pregnancy. Not recommended. May cause birth defects and bleeding problems.

Women who are nursing. This drug passes into breast milk. Talk to your doctor.

People who drive or operate machinery should exercise caution as even minor scrapes or bruises can cause excessive bleeding.

Alcohol may increase the effects of this drug.

Overdose: may cause severe bleeding and unconsciousness. Call your doctor or 911 immediately.

Stopping the drug. Talk to your doctor before you stop taking this drug as it may worsen the underlying condition.

If you miss a dose. Take the missed dose as soon as you remember it and the following dose as scheduled. Do not take a double dose.

Storage conditions: closed container; cool dry location away from excess moisture (not in the bathroom) and light; always out of reach of children.

Dietary precautions: None.