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ANTICOAGULANT THERAPY

Why is Anticoagulant Therapy being performed ?

Anticoagulant therapy makes the blood less likely to clot. It is used to prevent blood clots from developing in certain situations. For example, it is used for a period of a few months after an episode of thrombosis, or blood clot, in the leg veins. This prevents any extension of the thrombosis and allows time for the vein to heal. It is also used for a short time after some types of blood-vessel surgery such as coronary artery bypass to prevent blood clots from blocking the new blood-vessels. Sometimes, long-term anticoagulant therapy may be needed. This is common if the heart develops an abnormal rhythm called atrial fibrillation. When this happens, clots may develop in one of the heart chambers. Rarely, people may have an inherited tendency to thrombosis, which calls for lifelong protection. If people have had more than one thrombosis, even if no particular cause is found, long-term anticoagulant therapy may be recommended.

What Happens during Anticoagulant Therapy

In the early stages of an acute thrombosis which is often in hospital, a drug called heparin may be given to you by injection or through an intravenous drip or pump to reduce the clotting power of the blood. Treatment for clots in leg veins can often be given without admission to hospital. In this case heparin is injected under the skin. After a few days a change is made to oral treatment. The most commonly used oral drug is warfarin. Other related drugs may be used. They all act in the same way. They reduce the amount of blood-clotting factors made by the liver. This reduces the tendency of the blood to clot. The effect can be measured by a simple blood test, which compares the time taken for the patient's blood to clot with that of a person not on anticoagulants. The dose of anticoagulant treatment is adjusted so that it takes between two and four times as long for the patient's blood to clot. The dose of warfarin or other drug needed to achieve this effect varies from person to person. It can also vary at different times in the same person. It is therefore very important to have regular blood tests to make sure the dose is correctly adjusted. At first a test may need to be done every few days but once the dose of warfarin is established, a blood test is only needed every few weeks.

Possible Complications of Anticoagulant Therapy

Clearly if the ability of the blood to clot is reduced too much, there will be a risk of bleeding. This shows up as bruising or perhaps a bleeding nose. This is very rare if blood tests are done regularly and the dose of warfarin adjusted as necessary. However, the effect of a given dose of warfarin can be altered by other things. For example, alcohol will reduce the ability of the liver to break down warfarin. This will increase its effects and could cause bleeding. You should therefore limit alcohol intake to one glass of wine or one half pint of beer each day. Other drugs can also affect the activity of warfarin. Many antibiotics increase the activity of warfarin and increase the risk of bleeding. Some drugs can reduce the effectiveness of warfarin, so that one is not properly protected against thrombosis. It is therefore very important not to take any drugs or medicines without telling the doctor or pharmacist that warfarin is being taken. Aspirin in particular should be avoided because it increases the activity of warfarin and can also irritate the stomach, making bleeding more likely. If a mild analgesic is necessary, paracetamol in normal doses may safely be taken with anticoagulant therapy. Women of child-bearing age should avoid getting pregnant when taking warfarin. As with many drugs taken during early pregnancy, warfarin carries a small risk of affecting the baby. Patients who are on long-term warfarin and contemplating pregnancy should discuss the matter with the doctor. There are no long-term side-effects.

Afterwards

Your treatment will be stopped when the doctor feels that the risk of thrombosis has passed. The effect of the anticoagulant drug takes only a few days to wear off. The ability of the blood to clot returns to normal and precautions about alcohol and other drugs can be relaxed. If a leg thrombosis has occurred, the vein may have healed up completely but it may have been permanently damaged. This leads to swelling of the affected leg. This in itself may increase the chances of a recurrence of the thrombosis. In this case, you may be advised to wear an elastic support stocking. This will improve the circulation of the blood and reduce the chances of a recurrence.

If Anticoagulant Therapy is not performed

You would be at risk of thrombosis. What this means depends on your particular circumstances. For example, if there has been recent vascular surgery, it would mean there was an increased risk of blockage of the vessels that were operated on. If the clot is in a leg vein, it may be more likely to break loose and travel to the lung (pulmonary embolism). This causes shortness of breath, chest pain, coughing of blood and even death.