Examples

Generic Name	Brand Name
unfractionated heparin (UH)
warfarin	Coumadin

Low-molecular-weight heparins (LMWH)

Generic Name	Brand Name
dalteparin	Fragmin
enoxaparin	Lovenox
tinzaparin	Innohep

How It Works

Anticoagulants work by increasing the time it takes a blood clot to form. This also prevents a clot from getting bigger.

Why It Is Used

In people who have had pulmonary embolism, anticoagulants are used to prevent additional blood clots from forming and causing another episode of pulmonary embolism.

How Well It Works

Anticoagulants are effective in preventing pulmonary embolism and deep vein thrombosis.¹

Typically, warfarin is given for at least 3 to 6 months after pulmonary embolism to reduce the risk of having another blood clot.

Treatment with anticoagulants may continue throughout your life if your risk of having another pulmonary embolism remains high.

Side Effects

Bleeding is the most common side effect of anticoagulants.

Know the signs of bleeding

Call 911 if:

• You cough up blood.
• You vomit blood or what looks like coffee grounds.
• You pass maroon or very bloody stools.

Call your doctor right away if:

• You have new bruises or blood spots under your skin.
• You have a nosebleed that doesn't stop quickly.
• Your gums bleed when you brush your teeth.
• You have blood in your urine.
• Your stools are black and look like tar or have streaks of blood.
• You have heavy period bleeding or vaginal bleeding when you are not having your period.

If you are injured, apply pressure to stop the bleeding. Realize that it will take longer than you are used to for the bleeding to stop. If you can't get the bleeding to stop, call your doctor.

Warfarin may also cause a skin rash.

Heparin shots may cause irritation, pain, or bruising at the injection site.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

When you take anticoagulants, you need to take extra steps to avoid bleeding problems.

Warfarin. If you take warfarin, you need to:

• 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.

Know what to do if you miss a dose of anticoagulant.

Heparin. If you take heparin, you need to:

• Prevent falls and injuries.
• Prevent medicine interactions.

Pregnancy. Do not take warfarin if you are pregnant or may become pregnant. If you are taking warfarin and think you may be pregnant, call your doctor. Warfarin can cause birth defects. If you become pregnant while taking warfarin, your doctor may recommend that you switch to a low-molecular-weight form of heparin while you are pregnant. Long-term use of these heparin formulations is not recommended, because it is associated with osteoporosis and thrombocytopenia.

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.

References

Citations

1. Kearon C, Hirsh J (2007). Pulmonary embolism section of Venous thromboembolism. In DC Dale, DD Federman, eds., ACP Medicine, section 1, chap. 18. New York: WebMD.