Anticoagulants are a class of drugs commonly used to prevent the blood from forming dangerous clots that could result in a stroke. Often called “blood thinners,” anticoagulants are often the first medication prescribed by doctors following a stroke. By reducing the ability of the blood to clot — and thereby reducing the likelihood of coronary or vascular emboli—anticoagulants are frequently used in patients who are already at high-risk for stroke. Below is information on specific types of anticoagulants used for stroke prevention.


Heparin can be given intravenously or sub-cutaneously, but not by mouth. Heparin is sometimes used to reduce acute stroke damage or stroke risk in hospitalized patients. In addition, heparin may be used in hospitalized stroke patients to reduce the risk of blood clots forming in leg veins.

Warfarin (Coumadin® and others)

Warfarin is an anticoagulant drug (“blood thinner”) which is taken by mouth. Daily use of warfarin can reduce the risk of stroke in certain patients. For example, many patients with atrial fibrillation (an irregular heartbeat) should be prescribed warfarin. Use of warfarin requires careful monitoring, and you should closely follow your doctor’s recommendations, including regular blood tests. Let your doctor know if you’re taking any other medications.

Your doctor will start you on a low dose of Coumadin® and will have you see him or someone else to check your blood weekly. You want your blood levels to be within a certain range. The doctor wants you to be right in the middle, so you will have your blood drawn and the doctor will increase or decrease your dose based on the blood values and where he or she wants you to be.

Patients receiving Coumadin® also need to be very careful about their diet and activities to prevent problems while taking the medication. The levels of the drug in the body can be affected by the amount of vitamin K in your diet. Foods high in vitamin K include leafy green vegetables, green teas, as well as pork and beef liver. Patients should avoid large amounts of alfalfa, broccoli, asparagus, brussels sprouts, cauliflower, cabbage, kale, spinach, watercress, lettuce and turnip greens. You can still eat these foods, but eat the same amount regularly. For example, don’t eat a plateful of turnips every day for a week and then decide to stop eating them the next week. Large changes in the amount you eat can cause problems with your treatment.

Also, since Coumadin® is a fairly strong blood thinner, you have a chance of bleeding more than usual with common cuts, scrapes and falls. Use caution walking and with activities that place you at risk to fall or get hurt. Be careful while shaving, because a common cut may take longer to stop bleeding. Watch for blood in the urine, in the stools, or around the gums when eating and brushing teeth; bleeding from the nose; or bruising easily. If you notice abnormal or excessive bleeding, let your pharmacist and doctor know, and talk with them before you change or take any new medicines. Lastly, get an identification bracelet or necklace to let people, doctors and dentist know you are taking Coumadin®.