fondaparinuksi

Fondaparinux is a synthetic anticoagulant in the heparin family, marketed under names such as Arixtra. It is used to prevent and treat thromboembolic events and is distinguished by its defined chemical structure and predictable effects.

Mechanism of action: Fondaparinux is a pentasaccharide that binds to antithrombin III, inducing a conformational change that selectively inhibits factor Xa. It does not directly inhibit thrombin in typical therapeutic doses, and it has little direct effect on platelet function, reducing the risk of heparin-induced thrombocytopenia compared with unfractionated heparin.

Pharmacokinetics and administration: The drug is given by subcutaneous injection. It has high bioavailability and a relatively long elimination half-life, allowing once-daily dosing. It is predominantly excreted unchanged by the kidneys, so renal function significantly influences dosing and safety. Routine coagulation monitoring is not required in most patients.

Indications: Fondaparinux is used for prophylaxis of venous thromboembolism after major surgery, including orthopedic procedures such as hip or knee replacement, and for the prevention of VTE in other surgical settings. It is also used in the treatment of acute symptomatic DVT and PE when used as part of a non-heparin anticoagulation strategy, and it may be employed in patients with heparin-induced thrombocytopenia as an alternative anticoagulant.

Dosing and renal considerations: Prophylactic dosing commonly involves a fixed daily subcutaneous dose, adjusted for renal function and surgical context. Therapeutic dosing is weight-based and given subcutaneously once daily for a minimum period (often several days) as part of an anticoagulation regimen. Dose adjustments are required for patients with reduced renal function.

Safety and monitoring: There is no routine laboratory monitoring required for most users. A specific reversal agent is not available; management of major bleeding is supportive and guided by clinical judgment and renal function. Caution is advised in elderly patients, those with renal impairment, and patients undergoing neuraxial anesthesia due to bleeding risk.