Cardiac Medications


Warfarin (Coumadin) is the most commonly administered anticoagulant. This medication interferes with normal blood clotting mechanisms by reducing certain circulating blood proteins, which normally act to form blood clots. Warfarin may be used in patients with atrial fibrillation (a cardiac arrhythmia) to prevent stroke or embolism.

Warfarin may be given to patients with vein thrombosis (DVT, phlebitis) and in pulmonary embolism, which is a condition where blood clots travel from the veins in the legs to the lungs producing chest pain. Warfarin is also administered when blood clots form in the heart after a heart attack. On occasional Warfarin is also recommended in patients with severe blockages of coronary arteries.

While taking Warfarin the patient is at increased risk of bleeding. It is therefore necessary to monitor by a blood test called the prothrombin time, often referred to as PT. The PT is standardized between laboratories and reported as the INR (International Normalized Ratio). The INR is maintained between 2 and 3 to prevent clotting in atrial fibrillation, phlebitis and other conditions. With mechanical heart valves the INR is maintained between 2.5 and 3.5. The INR should be maintained within a narrow range in order to ensure that the blood is neither too thin nor too thick. Excessive thinning of the blood can lead to bleeding. Based on INR determinations, your physician should advise you as to your dose of Warfarin you should be taking. Often the dose of warfarin is not stable and may have to be adjusted frequently to keep the INR in the therapeutic range. .

Take a missed dose of Warfarin within eight hours but never take a double dose to make up for the missed dose. Be aware that you have a risk of bleeding. Being careful can reduce this risk. Never walk about barefoot, use an electric razor for shaving, use a soft toothbrush, and wear gloves to protect your hands when doing heavy work. Limit alcohol consumption (1-2 drinks/day).

There are many drugs, which interact with Warfarin and alter its effect. While taking Warfarin, do not take any new medications without the advice and knowledge of your physician.

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  Version 2.0, July 2004
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