What is heparin?

Heparin is a drug that stops your blood from clotting or forming blood clots. It is also called an anticoagulant or a blood thinner.

What is an infusion?

Infusion is when a drug or type of therapy is given through a needle or catheter (thin, flexible tube) that is placed into your blood vessels. Veins are the most common type of blood vessels used. When a catheter is placed in a vein it is called an "IV line."

When are you likely to have heparin infusion therapy?

Heparin may be the first treatment you get if you have a venous thromboembolism (VTE), also known as a blood clot. Such clots can be serious. You might have a clot in a deep vein, like one in the leg or arm. This is called a deep vein thrombosis or DVT.

If the DVT breaks loose from the wall of the vein and travels to the lungs, it is called a pulmonary embolism (PE). PEs can cut off some or all of the blood supply in the lungs. A blood clot could even travel to the brain, causing a stroke. This is why treatment is needed.

You may also get heparin to prevent blood clots after procedures, surgeries, or injuries that keep you from being able to move around, such as joint replacement surgeries.

Getting a heparin infusion

The drug heparin is sometimes given as an infusion through an IV line. It is important to have your blood drawn and tested to get the correct amount of heparin in your blood.

Your medical team will check to see how well heparin is working with a test called the partial thromboplastin time (PTT). This test will let them know how long it takes for your blood to clot. They will adjust your heparin dosing and order your next PTT tests to ensure the heparin is working correctly

Some infusion therapy is done in a hospital, but it is possible that you could have home infusion therapy. Your medical team will give you the information that you need if you are having infusion therapy at home or in the hospital.

What should you remember about taking heparin?

When you are taking heparin, be careful of any bruising or bleeding and report any concerns quickly to your medical team. If you get hurt when you are on a blood clot reducer, you can bleed too much. If you are in the hospital or other healthcare facility, please ask for help from an aide or nurse before getting out of bed. This will reduce the risk of falling.

When should you call the doctor or nurse about heparin side effects?

Call your doctor or notify your nurse if you are taking heparin and you have these side effects:

  • Trouble breathing, fast breathing or wheezing.
  • Bleeding that will not stop.
  • Bruising, rash or patches on the skin.
  • Rash or patches on the skin.
  • Sudden weakness or numbness on one side of the body.
  • Problems with headache, balance or confusion.
  • Problems seeing or hearing.
  • Pain in your chest or a fast heart rate.
  • Vomit that resembles coffee grounds.
  • Stools or bowel movements that are black, tarry or bloody
  • Urine that is brown or red.

Also, you should talk with your healthcare provider or pharmacist before you start to use any new drugs, over the counter products, or supplements. Other drugs can change the way heparin works. Your dose of the blood clot reducer may get too weak or too strong if it reacts to another drug.

Last reviewed by a Cleveland Clinic medical professional on 08/18/2020.


  • PDR.net. Heparin Sodium Intravenous Solutions. (https://www.pdr.net/drug-summary/heparin-sodium-intravenous-solutions?druglabelid=737) Accessed 8/17/2020.
  • National Home Infusion Association. About Home and Specialty Infusion. (https://www.nhia.org/about-infusion-therapy/) Accessed 8/17/2020.
  • Smythe MA, Priziola J, Dobesh PP, Wirth D, Cuker A, Wittkowsky AK. Guidance for the practical management of the heparin anticoagulants in the treatment of venous thromboembolism. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4715846/pdf/11239_2015_Article_1315.pdf.) J Thromb Thrombolysis. 2016;41(1):165-86. Accessed on 8/17/2020.
  • American Society of Health-System Pharmacists. Heparin Injection. (https://medlineplus.gov/druginfo/meds/a682826.html) Accessed 8/17/2020.

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