Arixtra Fondaparinux Sodium Injection

1. Indications and Usage
Prophylaxis of Venous Thromboembolism (VTE): Indicated for the prevention of venous thromboembolic events in patients undergoing major orthopedic surgery of the lower limb (hip fracture, major knee surgery, or hip replacement surgery).
Treatment of Acute Coronary Syndromes: Indicated for the treatment of unstable angina/non-ST-elevation myocardial infarction (UA/NSTEMI) and ST-elevation myocardial infarction (STEMI) in patients not scheduled for immediate invasive treatment.
2. Dosage and Administration
Orthopedic Surgery: The recommended dose is 2.5 mg once daily by subcutaneous injection. Initial administration should not be earlier than 6 hours after surgery and only when hemostasis has been established.
Acute Coronary Syndromes: The recommended dose is 2.5 mg once daily by subcutaneous injection. For the first dose in STEMI, it should be administered intravenously.
Administration: The drug should not be administered intramuscularly.
3. Mechanism of Action
Selective Xa Inhibitor: Fondaparinux sodium is a synthetic pentasaccharide that acts as an indirect and selective inhibitor of Factor Xa.
Anticoagulant Effect: It binds with high affinity to antithrombin III, inducing a conformational change that accelerates the neutralization of Factor Xa by antithrombin III, thereby interrupting the coagulation cascade and preventing thrombus formation.
4. Safety and Warnings
Bleeding Risk: Major risk includes severe or fatal bleeding. There is no known specific antidote for fondaparinux; management involves supportive care and transfusion if necessary.
Spinal/Epidural Hematoma: In patients treated with fondaparinux who undergo spinal puncture or spinal/epidural anesthesia, there is a risk of spinal/epidural hematomas, which can result in long-term or permanent paralysis.
Renal Impairment: The drug is eliminated primarily by the kidneys. It is contraindicated in patients with severe renal impairment (creatinine clearance <20 mL/min) due to increased bleeding risk.
5. Adverse Reactions and Clinical Research
Common Adverse Reactions: The most common adverse reactions include bleeding at the injection site, surgical site bleeding, anemia, and thrombocytopenia.
Clinical Research: Pivotal clinical trials (e.g., PENTHIFRA-REG, OASIS-5) have demonstrated that fondaparinux is effective in preventing VTE in orthopedic surgery and reducing ischemic events in ACS patients with a comparable or favorable bleeding profile compared to heparins.
6. Drug Interactions
Anticoagulants and Antiplatelets: Concomitant use with other anticoagulants (e.g., heparins, warfarin), antiplatelet agents (e.g., aspirin, clopidogrel), thrombolytics, or non-steroidal anti-inflammatory drugs (NSAIDs) increases the risk of bleeding.
Substrates of P-gp: Caution is advised when used with other substrates of the P-glycoprotein transporter.
7. Pharmaceutical Information
Active Ingredient: Fondaparinux sodium.
Excipients: Water for injections.
Appearance: A clear, colorless solution.
Storage: Store below 25°C. Do not freeze.