Pulmonary Embolism
Medications
Medicines can help prevent repeated episodes of pulmonary embolism by preventing new blood clots from forming or preventing existing clots from getting larger.
Medication Choices
Anticoagulants are prescribed when pulmonary embolism is diagnosed or strongly suspected. Normally, when an injury that causes bleeding occurs, the body sends out signals that cause the blood to clot at the wound. The clot naturally breaks down as the wound heals. A person who is prone to abnormal clotting has an imbalance between clot formation and clot breakdown. Anticoagulants prevent the production of certain proteins that are necessary for blood to clot. Although anticoagulants can prevent new clots from forming and prevent existing clots from getting larger, they do not break up or dissolve existing blood clots.
Heparin and warfarin are the two main types of anticoagulants used to treat pulmonary embolism.
Heparin
Heparin is an anticoagulant given by injection. It immediately affects the clotting system in your body. Oral anticoagulant medicine (warfarin) takes longer to start working.
- Initial treatment with a low-molecular-weight heparin (LMWH) usually is preferred because it can be given as an injection once or twice per day, and it may be given at home, allowing you to leave the hospital earlier.9 Blood tests are not usually needed to monitor LMWH's clotting effect.
- Unfractionated heparin is another form that can be used. It is given in the hospital. Unfractionated heparin is usually given continuously through your vein (intravenously, or IV), but can also be given as an injection under the skin. Frequent blood tests (usually every 6 hours) are required to monitor the clotting effects of this medicine.2
Early studies show that LMWH may be equally as effective as unfractionated heparin in most people with pulmonary embolism.12 However, it is still unclear whether LMWH is a good choice in treating a large pulmonary embolism. Some doctors may still prefer to use unfractionated heparin in these severe cases.
Both forms of heparin can cause severe bleeding in some people. The risk that either type will cause bleeding appears to be about the same.9 However, if bleeding occurs, unfractionated heparin can be stopped quickly, whereas LMWH has to wear off.
Warfarin (such as Coumadin)
Warfarin is an anticoagulant that is taken in pill form. It is usually started while a person is still being treated with heparin because it takes several days for warfarin to build up to a level that's effective. When the warfarin is at a proper level, heparin is discontinued and treatment with warfarin continues. Studies show that warfarin reduces the risk of another blood clot.13
Typically, full-dose warfarin is given for at least 3 to 6 months or longer after pulmonary embolism to reduce the risk of having another blood clot. Treatment with anticoagulants may continue throughout your life if the risk of having another pulmonary embolism remains high. Talk with your doctor about whether continuing low-dose warfarin after your first treatment might be right for you.
For those people with ongoing risk factors, such as cancer, anticoagulant treatment continues as long as those risk factors are present. Some people with inherited blood-clotting disorders or a history of recurrent deep vein thrombosis or pulmonary embolism may take oral anticoagulants for the rest of their lives.
Because warfarin can increase the risk of birth defects, pregnant women with pulmonary embolism are limited to taking heparin. A few days after the baby is born, a woman can switch from heparin to warfarin.
Thrombolytics
Clot-dissolving (thrombolytic) medicines are not commonly used to treat pulmonary embolism. Although they can quickly dissolve a blood clot, thrombolytics also greatly increase the risk of serious bleeding. They are occasionally used to treat a life-threatening pulmonary embolism.
What To Think About
After pulmonary embolism is diagnosed, a doctor considers:
- Whether anticoagulant medicines are appropriate.
- How long anticoagulants should be used.
If you have recently had a major stroke, surgery, or active internal bleeding, you usually cannot take anticoagulant or thrombolytic medicines. A vena cava filter may help to reduce the risk of another pulmonary embolism in this case.
It's important that you keep the following safety tips in mind when taking warfarin.
Safety tips for anticoagulants
- Take the medicine at the same time each day.
- Check with your doctor before using over-the-counter drugs, especially ones that contain ASA.
- Tell any new health professionals that you are taking medicine that affects how your blood clots.
- Be alert for signs of bleeding, and call the doctor immediately if any of the following symptoms occur:
- Blood in your urine, or red stools, or black stools that look like tar
- Nosebleeds that are hard to stop
- Spitting up blood
- New, excessive, or prolonged vaginal bleeding
- Frequent, severe bruising or tiny red or purple spots on the skin
- Talk to your doctor about medicines you are taking to find out how often you should have blood tests.
If you take warfarin (such as Coumadin):
- Get regular blood tests to ensure that you are taking the right amount of medicine.
- Eat a balanced diet. It is most important to maintain a consistent level of vitamin K foods in your diet. Vitamin K can interfere with the action of warfarin, making it more likely that your blood will clot. For more information, see:
- Avoid excessive use of alcohol. If you drink, do so only in moderation. Chronic drinking may cause liver damage and increase the effect of warfarin.
- Don't use tobacco of any kind.
- Avoid activities that have a high risk for injury, such as skiing, football, or other contact sports. If you are taking warfarin, an injury could result in excessive bleeding.
- Wear a seat belt anytime you are travelling in a car.
Preventing minor bleeding while taking anticoagulants
You may find it helpful to use the following items to lower your risk of bleeding:
- An electric razor
- A soft-bristled toothbrush and waxed floss
- Protective clothing, such as gloves and shoes
- Non-slip mats in the tub and shower
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| Author: | Douglas Dana Shannon Erstad, MBA/MPH | Last Updated: March 23, 2007 |
| Medical Review: | Anne C. Poinier, MD - Internal Medicine Caroline S. Rhoads, MD - Internal Medicine Jeffrey S. Ginsberg, MD - Hematology | |
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