What is the use of Arixtra (fondaparinux)?

From the Guidelines

Arixtra (fondaparinux sodium) should be used with caution in patients with renal insufficiency and is contraindicated in those with severe renal impairment (CrCl <30 mL/min), as it is eliminated exclusively by the kidney and can increase the risk of hemorrhages in patients with renal failure 1.

Key Considerations

• Arixtra is an anticoagulant medication that works by inhibiting Factor Xa, reducing the formation of dangerous clots.
• It is typically administered as a once-daily subcutaneous injection, with dosing usually at 2.5 mg for prevention of deep vein thrombosis (DVT) and weight-based dosing for treatment of existing clots.
• The medication should be injected at the same time each day, preferably in the lower abdominal area.
• Unlike heparin, Arixtra doesn't require routine blood monitoring in most cases, though kidney function should be assessed before starting therapy.
• Common side effects include bleeding risk, injection site reactions, and anemia.
• Patients should avoid other blood thinners unless specifically prescribed together by their doctor, and should inform all healthcare providers about taking this medication before any procedures.

Important Warnings

• Arixtra is contraindicated in patients with severe kidney impairment or low body weight (<50 kg) for certain indications.
• Caution is needed in elderly patients or those with moderate kidney dysfunction.
• Fondaparinux should not be used to support PCI because of the risk of catheter thrombosis, as noted in the 2025 ACC/AHA/ACEP/NAEMSP/SCAI guideline for the management of patients with acute coronary syndromes 1.

Clinical Evidence

• The OASIS-5 trial showed that fondaparinux was similar to enoxaparin in the risk for ischemic events at 9 days, but it reduced major bleeding 1.
• A meta-analysis comparing low-molecular-weight heparin to UFH in patients with ACS without ST-segment elevation across 5 randomized trials showed no significant difference in death or MI or in the risk of major bleeding 1.
• The use of fondaparinux in patients with heparin-induced thrombocytopenia (HIT) has been supported by several studies, including a retrospective study that compared 133 patients treated with fondaparinux with matched control patients using a propensity score 1.

From the FDA Drug Label

Fondaparinux sodium injection is a Factor Xa inhibitor (anticoagulant) indicated for: Prophylaxis of deep vein thrombosis (DVT) in patients undergoing hip fracture surgery (including extended prophylaxis), hip replacement surgery, knee replacement surgery, or abdominal surgery. Treatment of DVT or acute pulmonary embolism (PE) when administered in conjunction with warfarin.

The drug Arixtra is also known as fondaparinux sodium injection. It is used for:

• Prophylaxis of deep vein thrombosis (DVT) in patients undergoing certain surgeries
• Treatment of DVT or acute pulmonary embolism (PE) when administered with warfarin. 2

From the Research

Overview of Arixtra

• Arixtra, also known as fondaparinux, is a synthetic pentasaccharide anticoagulant that binds to antithrombin and inhibits the action of factor Xa 3.
• It is used for the prevention of venous thromboembolism (VTE) following major orthopaedic surgery, such as hip replacement, elective major knee or hip fracture surgery 3, 4.

Efficacy of Arixtra

• Fondaparinux has been shown to be more effective than enoxaparin in preventing VTE at day 11 in patients undergoing hip replacement, elective major knee or hip fracture surgery 3.
• A meta-analysis of four trials demonstrated that patients receiving fondaparinux had a >50% reduction in the relative risk of VTE at day 11 3.
• Fondaparinux has also been shown to be effective in preventing VTE in other surgical and medical settings, such as high-risk abdominal surgery and acutely ill medical patients 5.

Safety of Arixtra

• Fondaparinux has been generally well tolerated in clinical trials, with a similar safety profile to reference comparators 6.
• However, fondaparinux recipients had a significantly higher incidence of overt bleeding with a bleeding index > or =2 in some studies, although there was no increase in fatal bleeding, bleeding into a critical organ or bleeding leading to reoperation 3, 4.
• The bleeding risk is related to the timing of the first dose, and initiating fondaparinux between 6 and 8 hours after surgery can minimize the bleeding risk 3.

Clinical Use of Arixtra

• Fondaparinux is used for the prevention of deep vein thrombosis in patients who have had orthopedic surgery, as well as for the treatment of deep vein thrombosis and pulmonary embolism 7.
• However, its use is limited in certain patient populations, such as the elderly, low-weight patients, and those with renal impairment or receiving spinal anesthesia 7.