Other Brands/Names

Arixtra, Diviti, Fondarin, Forixtra, Venax, Vasola.

How It Works

Fondaparinux is a synthetic anticoagulant (blood thinner). It acts by selectively binding to antithrombin III, a small protein that inactivates several enzymes in the coagulation cascade. Through this action, antithrombin III helps prevent the formation of abnormal clots.

Fondaparinux also inhibits activated factor X and neutralizes factor Xa, both of which participate in blood clotting. As a result, the clotting process is disrupted and the development of clots is prevented.

Indications

Fondaparinux is used in the following clinical situations:

• Prevention of blood clot formation:
  

  • Adult patients undergoing orthopedic surgery on the lower limbs.

  • Adult patients undergoing abdominal surgery who are at high risk for clot-related complications.

  • Adult patients considered at risk for developing clots.

• Treatment of the following diseases:
  

  • Venous thrombosis in the lower extremities (superficial venous thrombosis).

  • Chest pain due to coronary heart disease that does not require immediate PCI (coronary artery dilation).

  • Deep vein thrombosis.

  • Pulmonary embolism, in which a clot blocks an artery in the lungs.

Contraindication

Fondaparinux is contraindicated in patients with:

• Active bleeding.

• Infective endocarditis (bacterial infection of the heart lining and valve surfaces).

• A history of low platelet counts related to prior heparin therapy.

• Body weight < 50 kg who are scheduled for major surgery on the hip, knee, or abdomen.

• Severe kidney disease.

Side Effects

Possible adverse effects include:

• Anemia (low red blood cell count)

• Fever

• Nausea and vomiting

• Constipation

• Skin rash

• Swelling

• Dizziness

• Headache

• Blood pressure disorders

• Elevated liver enzymes

• Post-operative wound issues

• Allergic reactions

A potentially fatal effect is spinal hematoma, a clot that can compress the spinal cord and may cause permanent paralysis.

Types

This drug is available as 2.5 mg/0.5 mL injections.

Dosage

Fondaparinux is administered subcutaneously. The dose is adjusted to body weight and the treatment purpose.

• Treatment of superficial venous thrombosis
  
  • 2.5 mg once daily for 30–45 days.

• Prevention of clot formation during surgery
  
  • 2.5 mg once daily, started 6–8 hours after surgery, for at least 5–9 days.
  • In patients at high risk of clots, give for 6–14 days.

• Treatment of venous clots
  

  • Body weight < 50 kg: 5 mg once daily.

  • Body weight 50–100 kg: 7.5 mg once daily.

  • Body weight > 100 kg: 10 mg once daily.

  • Duration: 5–9 days or until the patient transitions to an oral anticoagulant.

Safety

Pregnant Women

This drug is classified as FDA category B. Animal studies have not shown risk to the fetus, but adequate studies in pregnant women are lacking.

Breastfeeding Mothers

Fondaparinux can pass into breast milk. Do not use without consultation and approval from a physician.

Drug Interactions

Fondaparinux may increase bleeding risk when used with:

• Other anticoagulants such as desirudin or heparin.

• A fibrinolytic agent used to dissolve clots.

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