Coumadin, also called warfarin, is a blood thinner that acts by opposing the action of vitamin K in the liver. Vitamin K is involved in a specific process that activate the protein involved in the clotting of blood. The safe and effective dose of warfarin falls in a very narrow range. When you begin taking coumadin, your doctor will work with you to find the minimum effective dose. It is important that you precisely follow the dosing and diet guidelines given by your doctor.
Dosing
Your doctor will begin with an estimated dose of between two and five milligrams per day, and will adjust the dosing based on blood tests that measure the time your blood takes to clot. Prior research has established specific ranges for clotting time depending on the condition being treated. Coumadin is commonly given to treat deep vein thrombosis and atrial fibrillation and is also given after a heart attack. It can also be given to prevent blood clots from forming if you have a mechanical heart valve. Taking too much coumadin can raise your risk of dangerous bleeding, but taking too little coumadin will be ineffective, allowing blood clots to form. You will notice the effects of changing your dose of coumadin within four to five days.
Vitamin K & Coumadin
The effectiveness of coumadin depends on the amount of vitamin K in your diet. Vitamin K is involved in a specific biochemical process that allows proteins to interact with the mineral calcium, which is important in blood clotting and bone structure. Coumadin prevents this process from happening by deactivating a certain proportion of blood clotting proteins.
Diet
Vitamin K is found in high amounts in green leafy vegetables and in certain vegetable oils, such as soybean and canola oil. Multivitamins and some dietary supplements may also contain vitamin K. It is important to keep your vitamin K intake constant when taking coumadin. Your doctor will give you a list of foods that contain vitamin K, along with specific dietary guidelines that you'll need to follow while on coumadin.
Safety
Do not change your diet or start or stop taking other medication or dietary supplements without first alerting your doctor. Many herbal supplements and foods can change how your blood clots, affecting the appropriate dosage of coumadin. Seek emergency medical attention if you experience uncontrolled bleeding; injury; hives; rash; itching or difficulty breathing; chest pain; joint or muscle pain; difficulty moving; darkened skin; abnormal sensation; blood in your urine, vomit or stool; or coagulated blood that may look like coffee grounds.
