Heparin Side Effects

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

Applies to heparin: solution.

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:

Less common side effects

• abdominal or stomach pain or swelling
• back pain or backaches
• bleeding from the gums when brushing teeth
• blood in the urine
• constipation
• coughing up blood
• dizziness
• headaches, severe or continuing
• heavy bleeding or oozing from cuts or wounds
• joint pain, stiffness, or swelling
• menstrual bleeding, unexpected or unusually heavy
• unexplained bruising or purplish areas on the skin
• unexplained nosebleeds
• vomiting of blood or material that looks like coffee grounds

Rare side effects

• blood under the skin (blood blister) at the place of injection
• chest pain
• chills or fever
• fast or irregular breathing
• irritation, pain, redness, or ulcers at the place of injection
• itching and burning feeling, especially on the bottom of the feet
• nausea or vomiting
• numbness or tingling in the hands or feet
• pain, coldness, or blue color of the skin on the arms or legs
• peeling of the skin
• puffiness or swelling of the eyelids or around the eyes
• shortness of breath
• skin color change, especially near the place of injection or in the fingers, toes, arms, or legs
• skin rash, hives, or itching
• tearing of the eyes
• tightness in the chest
• trouble with breathing
• wheezing

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]

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