What is heparin?
Heparin is a fast-acting blood thinner that is given through an intravenous (IV) line in the arm or injected under the skin. Heparin makes the blood less sticky, preventing new blood clots from forming and stopping existing clots from growing larger.
Standard heparin, called unfractionated heparin, was once the standard initial treatment for DVT and PE. Although effective, standard heparin has mostly been replaced by a new kind of heparin called Low Molecular Weight Heparin.
| Heparin | |
| Names: | Heparin |
| How it is given: | Injected under the skin (subcutaneous) or injected through a needle inserted into a vein in your arm (intravenous, or IV) |
| What it is used for: | |
| You should not be treated with it if: |
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| Pregnancy/nursing: | The safety of this medication during pregnancy is unknown; you and your doctor should discus the possible risks and benefits before using this medication if you are pregnant. Heparin is not excreted in breast milk and is probably safe for nursing mothers.1 |
Who might receive heparin?
While heparin can be used as an initial treatment for DVT, it has mostly been replaced by Low Molecular Weight Heparin (LMWH) for this purpose. Research has shown that LMWH is better at preventing clots and is less likely to cause dangerous bleeding.2 Either standard heparin or LMWH may be used to treat pulmonary embolism (PE), a blood clot that formed in the arm or leg veins and traveled to block an artery in the lungs.2 Heparin is usually given in the hospital for 5 to 10 days after a DVT or PE.4
If you are at risk for blood clots because you are having certain types of surgery (such as knee or hip surgery) or because you are immobilized in the hospital, you may receive heparin to prevent blood clots. When given in this way, heparin reduces the risk of DVT or PE by 60% to 70%.6 For general surgery patients at high risk for blood clots, both standard heparin and LMWH are equally effective.5
What are the risks of heparin?
Because heparin has an immediate effect on the blood's ability to clot, it can lead to dangerous excessive bleeding. The risk of bleeding increases as the dose of heparin increases. If you are given too much heparin you may bleed too much, but if you are not given enough heparin your blood may continue to form dangerous clots.
Women, especially older women, are at a higher risk for bleeding complications from blood-thinning medications, including heparin. To make sure you are receiving the right dose of heparin, you will need regular blood tests to measure the time it takes for your blood to clot. If your blood is taking too long to clot, your heparin dose will be lowered. Blood tests are usually done 6 hours after starting heparin, and then once daily for as long as you are taking it.
Call your doctor immediately if you notice any of these signs of bleeding problems while taking heparin:
- Unusual or excessive bleeding from a minor injury
- Unusual bruising
- A rash or dark spots under the skin
- Muscle weakness
- Tingling or numbness, especially in the legs
- Bloody or dark urine or stool
- Severe headache or stomach pain
Another possible side effect of heparin is loss of bone density: long-term use of heparin has been linked to an increased risk of osteoporosis.7 However, most women being treated for DVT or PE will receive heparin for only a short time, and will be switched to another type of blood thinner (usually warfarin) for long-term blood clot prevention.
I am receiving heparin. What should I know?
Before receiving heparin, make sure your doctor knows about all medications you are taking, including prescription drugs, over-the-counter medications, and any dietary supplements including vitamins, minerals, or herbal supplements. Some medications can increase your chance of bleeding when you take heparin, including aspirin, ibuprofen (Motrin, Advil), naproxen (Aleve), and other NSAIDs (non-steroidal anti-inflammatory drugs).
Be sure to tell your doctor or dentist you are taking heparin before you have any type of surgery or dental procedure, and before you start taking any new medication.
See also: Heparin & Stroke
