Generic name: heparin (injection) [ HEP-a-rin ]
Brand names: Hep-Pak (obsolete), Heparin Lock Flush (obsolete), Hep-Pak CVC (obsolete), Hep-Lock (obsolete), Heparin Sodium ADD-Vantage
Drug class: Heparins

Medically reviewed by Kaci Durbin, MD. Last updated on Dec 27, 2023.

What is heparin injection?

Heparin is an anticoagulant (blood thinner) that prevents the formation of blood clots.

Heparin is used to treat and prevent blood clots caused by certain medical conditions or medical procedures. It is also used before surgery to reduce the risk of blood clots.

Do not use heparin injection to flush (clean out) an intravenous (IV) catheter. A separate product is available to use as catheter lock flush. Using the wrong type of heparin to flush a catheter can result in fatal bleeding.

Warnings

Do not use heparin injection to flush (clean out) an intravenous (IV) catheter, or fatal bleeding could result. A separate product is available to use as catheter lock flush.

You should not use heparin if you have uncontrolled bleeding or a severe lack of platelets in your blood. Do not use this medicine if you have ever been diagnosed with “heparin-induced thrombocytopenia,” or low platelets caused by heparin or pentosan polysulfate.

Heparin increases your risk of bleeding, which can be severe or life-threatening. You will need frequent tests to measure your blood-clotting time.

Call your doctor or seek emergency medical attention if you have unusual bleeding or bruising, severe stomach or back pain, unusual tiredness, a nosebleed, blood in your urine or stools, coughing up blood, or any bleeding that will not stop.

Heparin can cause you to have bleeding episodes while you are using it and for several weeks after you stop.

Certain medicines can increase your risk of bleeding while you are using heparin, such as aspirin or other NSAIDs (non-steroidal anti-inflammatory drugs) including ibuprofen (Advil, Motrin), naproxen (Aleve, Naprosyn, Naprelan, Treximet), celecoxib (Celebrex), diclofenac (Arthrotec, Cambia, Cataflam, Voltaren, Flector Patch, Pennsaid, Solareze), indomethacin (Indocin), meloxicam (Mobic), ketoprofen (Orudis), ketorolac (Toradol), mefenamic acid (Ponstel), nabumetone (Relafen), piroxicam (Feldene), and others. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.

Do not use heparin injection to flush (clean out) an intravenous (IV) catheter, or fatal bleeding could result. A separate product is available to use as catheter lock flush.

Before taking this medicine

You should not use this medicine if you are allergic to heparin or pork products, or if you have:

• a history of low platelets in your blood caused by using heparin or pentosan polysulfate;

• a severe lack of platelets in your blood; or

• uncontrolled bleeding.

You may not be able to use heparin if you are unable to receive routine blood-clotting tests at the proper intervals during treatment.

To make sure heparin is safe for you, tell your doctor if you have ever had:

• an infection of the lining of your heart (also called bacterial endocarditis);

• severe or uncontrolled high blood pressure;

• a bleeding or blood clotting disorder;

• a stomach or intestinal disorder;

• liver disease;

• if you use a blood thinner (warfarin, Coumadin, Jantoven) and you have routine "INR" or prothrombin time tests; or

• if you are having a menstrual period.

It is not known whether heparin will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant. You may need to use a form of heparin that does not contain a preservative.

You should not breastfeed while using this medicine.

How should I use heparin injection?

Heparin is injected under the skin or as an infusion into a vein. A healthcare provider will give your first dose and may teach you how to properly use the medication by yourself.

Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose. Use the medicine exactly as directed.

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you don't understand all instructions.

Prepare an injection only when you are ready to give it. Do not use the medicine if it has changed colors or has particles in it. Call your pharmacist for new medicine.

Do not use a prefilled syringe when giving this medicine to a child. The prefilled syringe contains more than a child's dose of heparin.

Heparin increases your risk of bleeding, which can be severe or life-threatening. You will need frequent tests to measure your blood-clotting time. The timing of these tests is very important in helping your doctor determine whether it is safe for you to continue using this medicine.

If you need surgery, dental work, or a medical procedure, tell the care provider ahead of time that you are using heparin.

Store at room temperature away from moisture and heat.

Use a needle and syringe only once and then place them in a puncture-proof "sharps" container. Follow state or local laws about how to dispose of this container. Keep it out of the reach of children and pets.

You may be switched from injectable heparin to an oral (taken by mouth) blood thinner. Do not stop using the injection until your doctor tells you to. You may need to use both the injection and the oral forms for a short time.

Related/similar drugs

amlodipine, lisinopril, aspirin, metoprolol, carvedilol, clopidogrel, Eliquis, atenolol, propranolol, warfarin

What happens if I miss a dose?

Call your doctor for instructions if you miss a dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include easy bruising, nosebleeds, blood in your urine or stools, black or tarry stools, or any bleeding that will not stop.

What should I avoid while using heparin injection?

Avoid medication errors by using only the form and strength your doctor prescribes.

Ask your doctor before taking a nonsteroidal anti-inflammatory drug (NSAID). Using an NSAID with heparin may cause you to bruise or bleed easily.

Heparin injection side effects

Get emergency medical help if you have signs of an allergic reaction to heparin: nausea, vomiting, sweating, hives, itching, trouble breathing, swelling of your face, lips, tongue, or throat, or feeling like you might pass out.

Heparin may cause you to bleed more easily, which can be severe or life-threatening. You may also have bleeding on the inside of your body. Seek emergency medical attention if you have:

• skin warmth or discoloration;

• chest pain, irregular heartbeats;

• shortness of breath, dizziness, anxiety, sweating;

• any unusual bleeding or bruising;

• severe pain or swelling in your stomach, lower back, or groin;

• dark or blue-colored skin on your hands or feet;

• nausea, vomiting, loss of appetite;

• unusual tiredness;

• any bleeding that will not stop; or

• nosebleed, blood in your urine or stools, black or tarry stools, or coughing up blood or vomit that looks like coffee grounds.

Heparin can cause you to have bleeding episodes while you are using it and for several weeks after you stop.

Bleeding may be more likely in older adults, especially women over 60 years of age

Stop using this medicine and call your doctor at once if you have:

• skin changes where the medicine was injected;

• fever, chills, runny nose, or watery eyes;

• easy bruising, unusual bleeding, purple or red spots under your skin; or

• signs of a blood clot - sudden numbness or weakness, problems with vision or speech, swelling or redness in an arm or leg.

Common heparin side effects may include:

• unusual bleeding or bruising;

• uncontrolled bleeding;

• allergic reactions; or

• abnormal liver function tests.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

What other drugs will affect heparin injection?

Ask your doctor before taking a nonsteroidal anti-inflammatory drug (NSAID) such as aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve), celecoxib, diclofenac, indomethacin, meloxicam, and others. Using an NSAID with heparin may cause you to bruise or bleed easily.

Tell your doctor about all your other medicines, especially:

• a blood thinner - warfarin, Coumadin, Jantoven;

• digitalis;

• tetracyclines;

• nicotine; or

• antihistamines.

This list is not complete and many other drugs may interact with heparin. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.

Frequently asked questions

• How and where is Heparin injection given?

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use heparin only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer

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