Medicines can help prevent repeated
pulmonary embolism by preventing new blood clots from
forming or preventing existing clots from getting larger.
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
needed 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 is an anticoagulant
given by injection. It immediately affects the clotting system in your body.
Oral anticoagulant medicine (warfarin) takes longer to start working.
- Low-molecular-weight heparin (LMWH) as initial treatment is usually preferred because it can be
given as an injection once or twice a day, and it may be given at home,
which allows you to leave the hospital earlier. 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 it can also be given as an injection under the skin. Frequent blood tests
are used to monitor the clotting effects of this
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
stopped and treatment with warfarin continues.
Typically, warfarin is given for at least 3 months 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.
Because warfarin can increase the risk of birth defects,
pregnant women with a risk of developing blood clots are limited to
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
What To Think About
After pulmonary embolism is
diagnosed, a doctor considers:
- Whether anticoagulant medicines are
- 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
vena cava filter may help to reduce the risk of
another pulmonary embolism in this case.
Safety with anticoagulant medicine
When you take anticoagulants, you need to take extra steps to avoid bleeding problems.
Heparin. If you take heparin:
Warfarin. If you take warfarin:
- Get regular blood tests.
- Prevent falls and injuries.
- Eat a steady diet, and pay attention to foods that contain vitamin K.
- Tell your doctors about all other medicines and vitamins that you take.
For more information, see:
- Warfarin: Taking Your Medicine Safely.