What are the precautions while taking Warfarin (blood thinner) ?
Warfarin is a blood thinner medication used to prevent the formation of blood clots within the heart and blood vessels. It is used in a variety of conditions involving the heart and blood vessels. Though it is a very effective medication, it has a narrow window of safety. This means that the dose has to be carefully adjusted with appropriate blood testing. A test known as prothrombin time with international normalized ratio (PT-INR) is used to adjust the dosage according to the condition for which it is given. Frequent monitoring is needed, because the effect of Warfarin in the body can be influenced by food and other medications which are taken along with it. For example, leafy vegetables and other foods which contain a lot of vitamin K will reduce the effectiveness of the drug. On the other hand certain medications increase the effectiveness of the drug by displacing it from the proteins in the blood, thereby increasing its effective blood level. So it is essential to check PT-INR whenever there is any change in the diet or medication pattern. Concomitant liver disease will also increase the bleeding risk with Warfarin as the factors needed for blood clotting are synthesized in the liver.
While taking Warfarin, a constant vigil has to be there for all potential types of bleeding which may otherwise go unnoticed. If any abnormal bleeding is noted, PT-INR has to be checked. Bleeding may be blood in stools, urine or vomitus. Bleeding into the skin can appear like bruises. Bleeding in the upper intestine (small intestine) manifest as black tarry stools instead of red stools in case of bleeding from the lower intestine (large intestine). Bleeding into brain can manifest a stroke with weakness of one side of the body with or without loss of consciousness.