Heparin Side Effects

Medically reviewed by Drugs.com. Last updated on Feb 20, 2025.

Applies to heparin: solution.

Precautions

It is very important that your doctor check you at regular visits after you leave the hospital for any problems or unwanted effects that may be caused by this medicine. If you are using the medicine at home, blood tests will be needed to check for unwanted effects. Be sure to keep all appointments.

Do not take aspirin, ibuprofen, or other anti-inflammatory medicines (eg, NSAIDs) while you are using heparin. Many nonprescription (over-the-counter [OTC]) medicines and some prescription medicines contain these ingredients. Check the labels of all medicines you take. There are many other medicines that may change the way heparin works or increase the chance of bleeding if they are used together with heparin. It is best to check with your doctor before taking any other medicine while you are using heparin.

You may bleed and bruise more easily while you are using this medicine. Stay away from rough sports or other situations where you could be bruised, cut, or injured. Tell your doctor about any falls, blows to the body or head, or other injuries, since serious bleeding may occur inside the body with this medicine. Be careful when using sharp objects, including razors and fingernail clippers. Avoid picking your nose. If you need to blow your nose, blow it gently. Check with your doctor right away if you notice any unusual bleeding or bruising; black, tarry stools; blood in the urine or stools; or pinpoint red spots on your skin.

Be careful when using a regular toothbrush, dental floss, or toothpick. Your medical doctor, dentist, or nurse may recommend other ways to clean your teeth and gums. Check with your medical doctor before having any dental work done.

This medicine may cause a serious type of allergic reaction called anaphylaxis. Anaphylaxis can be life-threatening and requires immediate medical attention. Tell your doctor right away if you have a rash; itching; swelling of the face, tongue, and throat; trouble breathing; or chest pain after you receive this medicine.

This medicine may cause new blood clots to form in some people while they are receiving the medicine or after it is stopped. Stop using this medicine and check with your doctor right away if you have pain in the chest, groin, or legs, especially the calves; difficulty with breathing; a sudden, severe headache; slurred speech; a sudden, unexplained shortness of breath; a sudden loss of coordination; or vision changes while using this medicine.

Make sure any doctor or dentist who treats you knows that you are using this medicine. You may need to stop using this medicine several days before having surgery or medical tests.

Serious side effects of heparin

Along with its needed effects, heparin may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor or nurse immediately if any of the following side effects occur while taking heparin:

After you stop using this medicine, it may still produce some side effects that need attention. During this period of time, Check with your doctor immediately if you notice the following side effects:

• black, tarry stools
• bleeding gums
• blood in the urine or stools
• pain in the chest, groin, or legs, especially calves of legs
• pinpoint red spots on the skin
• severe headaches of sudden onset
• sudden loss of coordination
• sudden shortness of breath for no apparent reason
• sudden slurred speech
• sudden vision changes
• unusual bleeding or bruising

For healthcare professionals

Applies to heparin: injectable kit, injectable solution, intravenous solution.

General adverse events

The most common adverse reaction was hemorrhage.^[Ref]

Cardiovascular

• Postmarketing reports: Hemorrhage, retroperitoneal hemorrhage^[Ref]

Hematologic

• Very common (10% or more): Thrombocytopenia (up to 30%)
• Frequency not reported: Plasma lipoprotein lipase increased
• Postmarketing reports: Heparin resistance^[Ref]

Hypersensitivity

• Frequency not reported: Conjunctivitis, cyanosis, tachypnea, feeling of oppression, angioneurotic edema, anaphylactic shock
• Postmarketing reports: Chills, fever, urticaria, asthma, rhinitis, lacrimation, headache, nausea, vomiting, anaphylactoid reactions, shock, itching, burning^[Ref]

Local

• Frequency not reported: Erythematous nodules, infiltrated and sometimes eczema-like plaques
• Postmarketing reports: Local irritation, erythema, mild pain, hematoma, ulceration, histamine-like reactions, skin necrosis^[Ref]

Immunologic

• Frequency not reported: Allergic reactions, hypereosinophilia
• Postmarketing reports: Heparin-induced thrombocytopenia, heparin-induced thrombocytopenia and thrombosis, generalized hypersensitivity reactions^[Ref]

Endocrine

• Frequency not reported: Hypoaldosteronism
• Postmarketing reports: Adrenal hemorrhage, acute adrenal insufficiency, fatal adrenal hemorrhage, aldosterone synthesis suppressed^[Ref]

Metabolic

• Frequency not reported: Plasma potassium increased, hyperkalemia, metabolic acidosis
• Postmarketing reports: Rebound hyperlipidemia^[Ref]

Musculoskeletal

• Frequency not reported: Significant bone demineralization, spontaneous bone fracture
• Postmarketing reports: Osteoporosis^[Ref]

Dermatologic

• Frequency not reported: Ecchymoses
• Postmarketing reports: Cutaneous necrosis, delayed transient alopecia^[Ref]

Hepatic

• Frequency not reported: Serum transaminases increased
• Postmarketing reports: ALT elevated significantly, AST elevated significantly^[Ref]

Genitourinary

• Postmarketing reports: Ovarian hemorrhage, priapism^[Ref]

Renal

• Frequency not reported: Renal function suppression^[Ref]

See also:

Frequently asked questions

• How and where is Heparin injection given?

Further information

Heparin side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer