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Arixtra 5 mg/dose Side Effects

Generic name: fondaparinux

Medically reviewed by Last updated on Sep 8, 2022.

Note: This document contains side effect information about fondaparinux. Some dosage forms listed on this page may not apply to the brand name Arixtra 5 mg/dose.

Applies to fondaparinux: subcutaneous solution.


Subcutaneous route (Solution)

Epidural or spinal hematomas, which may result in long-term or permanent paralysis, can occur in patients who are anticoagulated with low molecular weight heparins, heparinoids, or fondaparinux sodium and are receiving neuraxial anesthesia or undergoing spinal puncture. Use of indwelling epidural catheters, concomitant use of drugs affecting hemostasis (eg, NSAIDs, platelet inhibitors, or other anticoagulants), history of traumatic or repeated epidural or spinal puncture, spinal deformity, or spinal surgery may increase the risk of developing these hematomas. Monitor patients frequently for neurological impairment. If neurological compromise is noted, urgent treatment is necessary.

Serious side effects of Arixtra 5 mg/dose

Along with its needed effects, fondaparinux (the active ingredient contained in Arixtra 5 mg/dose) 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 fondaparinux:

More common

  • Pale skin
  • troubled breathing with exertion
  • unusual bleeding or bruising
  • unusual tiredness or weakness

Less common

  • Black, tarry stools
  • bladder pain
  • bleeding gums
  • blood in the urine or stools
  • blurred vision
  • chest pain
  • chills
  • collection of blood under the skin
  • confusion
  • convulsions
  • cough
  • decreased or cloudy urine
  • deep, dark purple bruise
  • difficult, burning, or painful urination
  • dizziness
  • dry mouth
  • fainting or lightheadedness when getting up from a lying or sitting position
  • fever
  • frequent urge to urinate
  • increased thirst
  • irregular heartbeat
  • itching, pain, redness, or swelling at the injection site
  • loss of appetite
  • lower back or side pain
  • muscle pain or cramps
  • nausea or vomiting
  • numbness or tingling in the hands, feet, or lips
  • pinpoint red spots on the skin
  • red, tender, or oozing skin at incision
  • shortness of breath
  • sore throat
  • sores, ulcers, or white spots on the lips or in the mouth
  • sudden sweating

Incidence not known

  • Back pain
  • bowel or bladder dysfunction
  • difficulty with swallowing
  • fast heartbeat
  • hives, itching, or skin rash
  • large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
  • leg weakness
  • numbness
  • paralysis
  • puffiness or swelling of the eyelids or around the eyes, face, lips, or tongue
  • tightness in the chest

Get emergency help immediately if any of the following symptoms of overdose occur while taking fondaparinux:

Symptoms of overdose

Other side effects of Arixtra 5 mg/dose

Some side effects of fondaparinux 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:

More common

  • Difficulty having a bowel movement
  • swelling
  • trouble sleeping

Less common

  • Acid or sour stomach
  • belching
  • diarrhea
  • heartburn
  • indigestion
  • pain
  • skin blisters
  • stomach discomfort, upset, or pain
  • tightness in the chest
  • unusual changes to site of surgery
  • wound drainage, increased

For Healthcare Professionals

Applies to fondaparinux: subcutaneous solution.


The most common adverse events were bleeding events.

The most serious adverse events were bleeding complications and thrombocytopenia.[Ref]


The majority of major bleeding events occurred during the first 4 days after surgery. Major bleeding incidence increased in patients weighing less than 50 kg and in patients with impaired renal function.[Ref]

Very common (10% or more): Anemia (19.6%)

Common (1% to 10%): Post-operative hemorrhage, major bleeding, minor bleeding, moderate thrombocytopenia, non-fatal major bleeding at surgical site, overt bleeding associated with a bleeding index of 2 or greater, prothrombin decreased, other clinically overt bleeding, bleeding

Uncommon (0.1% to 1%): Reoperation due to bleeding, non-fatal major bleeding at non-surgical site, severe thrombocytopenia, fatal bleeding, intracranial bleeding, thrombocythemia, abnormal platelets, coagulation disorder

Very rare (less than 0.01%): Hypertensive encephalopathy with intracranial bleeding, minor gastrointestinal bleeding

Postmarketing reports: Thrombocytopenia with thrombosis, aPTT elevation, intracerebral bleeding, retroperitoneal bleeding[Ref]


Very common (10% or more): Fever (13.6%)

Common (1% to 10%): Edema, post-operative wound infection, wound drainage increased, surgical site reaction, pain, chest pain

Uncommon (0.1% to 1%): Edema peripheral, wound secretion

Rare (less than 0.1%): Hot flushes[Ref]


Very common (10% or more): Nausea (11.3%)

Common (1% to 10%): Constipation, vomiting, diarrhea, dyspepsia, abdominal pain

Rare (less than 0.1%): Gastritis[Ref]


Common (1% to 10%): Hematoma, bruising

Rare (less than 0.1%): Injection site reaction

Frequency not reported: Local irritation (injection site bleeding, rash, pruritus)[Ref]


Common (1% to 10%): Increases in ALT, increases in AST

Uncommon (0.1% to 1%): Hepatic function abnormal, hepatic enzymes increased

Rare (less than 0.1%): Bilirubinemia

Frequency not reported: Increases in bilirubin[Ref]


Common (1% to 10%): Hypotension, hypertension[Ref]


Common (1% to 10%): Rash, purpura, bullous eruption (includes localized blister)

Uncommon (0.1% to 1%): Pruritus

Rare (less than 0.1%): Flushing[Ref]

Nervous system

Common (1% to 10%): Headache, dizziness

Rare (less than 0.1%): Somnolence, vertigo, fatigue, syncope

Postmarketing reports: Spinal or epidural hematoma[Ref]


Common (1% to 10%): Urinary tract infection, urinary retention

Rare (less than 0.1%): Edema genital[Ref]


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


Common (1% to 10%): Leg pain, back pain[Ref]


Common (1% to 10%): Insomnia, confusion

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


Common (1% to 10%): Pneumonia, coughing, epistaxis

Rare (less than 0.1%): Dyspnea[Ref]


Rare (less than 0.1%): Allergic reaction

Very rare (less than 0.01%): Angioedema, anaphylactoid/anaphylactic reaction

Postmarketing reports: Serious allergic reactions[Ref]


1. "Product Information. Arixtra (fondaparinux)." Organon (2002):

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

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

4. Savi P, Chong BH, Greinacher A, et al. "Effect of fondaparinux on platelet activation in the presence of heparin-dependent antibodies. A blinded comparative multicenter study with unfractionated heparin." Blood 105 (2005): 139-41

5. Warkentin TE, Maurer BT, Aster RH "Heparin-induced thrombocytopenia associated with fondaparinux." N Engl J Med 356 (2007): 2653-5; discussion 2653-5

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.