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Lovenox Side Effects

Generic name: enoxaparin

Medically reviewed by Last updated on Jun 27, 2021.

Note: This document contains side effect information about enoxaparin. Some of the dosage forms listed on this page may not apply to the brand name Lovenox.

In Summary

Common side effects of Lovenox include: anemia and hemorrhage. Other side effects include: fever. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to enoxaparin: solution


Injection route (Solution)

Epidural or spinal hematomas, which may result in long-term or permanent paralysis, may occur in patients who are anticoagulated with low molecular weight heparins or heparinoids and are receiving neuraxial anesthesia or undergoing spinal puncture. Factors that can increase the risk of developing these hematomas include: use of indwelling epidural catheters, concomitant use of drugs affecting hemostasis such as NSAIDs, platelet inhibitors, or other anticoagulants, or history of traumatic or repeated epidural or spinal puncture, spinal deformity, or spinal surgery. Optimal timing between the administration of enoxaparin sodium and neuraxial procedures is not known. Monitor patients frequently for neurological impairment. If neurological compromise is noted, urgent treatment is necessary. Consider risks/benefits before neuraxial intervention in patients anticoagulated or to be anticoagulated for thromboprophylaxis.

Side effects requiring immediate medical attention

Along with its needed effects, enoxaparin (the active ingredient contained in Lovenox) 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 immediately if any of the following side effects occur while taking enoxaparin:

More common

Less common

  • Bruising
  • chest discomfort
  • collection of blood under the skin
  • confusion
  • continuing bleeding or oozing from the nose and/or mouth, or surgical wound
  • convulsions (seizures)
  • fever
  • irritability
  • lightheadedness
  • lower back pain
  • pain or burning while urinating
  • swelling of the hands or feet
  • tightness in the chest
  • uncontrolled bleeding at the site of injection
  • vomiting of blood or material that looks like coffee grounds
  • wheezing


  • Back pain
  • burning, pricking, tickling, or tingling sensation
  • chest pain
  • chills
  • cough
  • decreased urine output
  • dilated neck veins
  • dizziness or lightheadedness when getting up suddenly from a lying or sitting position
  • extreme fatigue
  • fainting
  • fast or irregular heartbeat
  • general feeling of discomfort or illness
  • irregular breathing
  • leg weakness
  • problems with bowel or bladder function
  • skin rash or hives
  • sneezing
  • sore throat
  • sudden fainting
  • swelling of the face, fingers, feet, genitals, mouth, or tongue
  • thickening of the bronchial secretions
  • troubled breathing
  • weight gain

Incidence not known

  • Abdominal or stomach pain
  • deep, dark purple bruise
  • hives or welts
  • irregular heartbeat
  • itching, pain, redness, or swelling
  • large, flat, blue, or purplish patches in the skin
  • nausea or vomiting
  • nervousness
  • numbness or tingling in the hands, feet, or lips
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • redness of the skin
  • skin rash
  • unusual tiredness or weakness
  • weakness or heaviness of the legs

Side effects not requiring immediate medical attention

Some side effects of enoxaparin may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

Less common

  • Diarrhea
  • irritation, pain, or redness at the place of injection

For Healthcare Professionals

Applies to enoxaparin: injectable solution


The most common adverse reactions were bleeding, anemia, thrombocytopenia, elevation of serum aminotransferase, diarrhea, and nausea.[Ref]


Common (1% to 10%): Major hemorrhage

Uncommon (0.1% to 1%): Atrial fibrillation, heart failure

Frequency not reported: Hemorrhage

Postmarketing reports: Shock, valve thrombosis in patients with prosthetic heart valves[Ref]


Common (1% to 10%): Thrombocytopenia, anemia, platelet counts between 100,000 and 50,000/mm3

Uncommon (0.1% to 1%): Platelet counts less than 50,000/mm3

Frequency not reported: Thrombocytosis

Postmarketing reports: Hemorrhagic anemia, platelet count increased, eosinophilia[Ref]


Common (1% to 10%): ALT increased asymptomatically, AST increased asymptomatically

Frequency not reported: Hepatic enzymes increased

Postmarketing reports: Hepatocellular liver injury, cholestatic liver injury[Ref]


Common (1% to 10%): Nausea, diarrhea

Uncommon (0.1% to 1%): Retroperitoneal hemorrhage[Ref]


Common (1% to 10%): Injection site hematoma, injection site pain, other injection site reaction

Uncommon (0.1% to 1%): Local irritation, injection site skin necrosis

Postmarketing reports: Injection site nodules[Ref]


Common (1% to 10%): Urticaria, pruritus, erythema

Uncommon (0.1% to 1%): Bullous dermatitis

Postmarketing reports: Cutaneous vasculitis, skin necrosis, alopecia[Ref]


Common (1% to 10%): Peripheral edema, edema

Rare (less than 0.1%): Hyperkalemia

Postmarketing reports: Hyperlipidemia, hypertriglyceridemia[Ref]


Common (1% to 10%): Allergic reaction

Rare (0.01% to 0.1%): Anaphylactic/anaphylactoid reaction

Very rare (less than 0.01%): Immuno-allergic thrombocytopenia

Postmarketing reports: Immuno-allergic thrombocytopenia with thrombosis[Ref]


Common (1% to 10%): Dyspnea

Uncommon (0.1% to 1%): Lung edema, pneumonia[Ref]


Uncommon (0.1% to 1%): Hematuria[Ref]


Common (1% to 10%): Confusion[Ref]


Common (1% to 10%): Fever[Ref]

Nervous system

Uncommon (0.1% to 1%): Intracranial hemorrhage

Postmarketing reports: Headache, spinal hematoma[Ref]


Postmarketing reports: Osteoporosis following treatment longer than 3 months[Ref]


1. Cerner Multum, Inc. "Australian Product Information." O 0

2. Cerner Multum, Inc. "UK Summary of Product Characteristics." O 0

3. "Product Information. Lovenox (enoxaparin)." Rhone-Poulenc Rorer, Collegeville, PA.

Further information

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

Some side effects may not be reported. You may report them to the FDA.