Adult: <50 kg: 5 mg once daily; 50-100 kg: 7.5 mg once daily; >100 kg: 10 mg once daily. Treatment duration: 5-9 days, or until oral anticoagulation is established.
Subcutaneous Prophylaxis of deep vein thrombosis in abdominal and orthopaedic surgery
Adult: 2.5 mg once daily, starting 6-8 hr after surgery, continue for at least 5-9 days. In high-risk patients, 6-14 days or up to 32 days in hip fracture.
Renal Impairment
Subcutaneous: Venous thromboembolism:
CrCl (mL/min)
Dosage
<30
Contraindicated.
Superficial vein thrombosis; Prophylaxis of deep vein thrombosis in abdominal and orthopaedic surgery:
CrCl (mL/min)
Dosage
<20
Contraindicated.
20-50
1.5 mg once daily.
Contraindications
Active major bleeding, bacterial endocarditis, history of heparin-induced thrombocytopenia. Patient weighing <50 kg and who are to undergo hip fracture, hip replacement, knee replacement or abdominal surgery. Severe renal impairment (CrCl <20 mL/min if used in venous thromboembolism (VTE) prophylaxis and treatment of superficial vein thrombosis; CrCl <30 mL/min in the treatment of VTE).
Special Precautions
Patient w/ increased risk of haemorrhage (e.g. congenital or acquired bleeding disorders, history or active GI ulceration, intracranial haemorrhage, recent brain, spinal or ophth surgery); body wt <50 kg. Increased risk of spinal or epidural haematomas in patient undergoing neuraxial (spinal/epidural) anaesth or spinal puncture esp w/ post-op use of indwelling epidural catheters and concurrent use of medications affecting haemostasis. Moderate renal and severe hepatic impairment. Pregnancy and lactation.
Adverse Reactions
Hip-fracture, hip-replacement, or knee-replacement surgery: Anaemia, fever, nausea, oedema, constipation, rash, vomiting, insomnia, increased wound drainage, hypokalaemia, UTI, dizziness, purpura, hypotension, confusion, bullous eruption, urinary retention, haematoma, major bleeding, diarrhoea, dyspepsia, post-op haemorrhage, and headache. Treatment of venous thromboembolism: Constipation, headache, insomnia, fever, nausea, UTI, and coughing. Abdominal surgery: Post-op wound infection and haemorrhage, fever, surgical site reaction, anaemia, HTN, pneumonia, vomiting. Potentially Fatal: Epidural or spinal haematomas that may result in permanent paralysis.
Increased risk of bleeding w/ (e.g. desirudin, fibrinolytic drugs, glycoprotein IIb/IIIa-receptor antagonists, heparin, heparinoids or LMWH).
Action
Description: Mechanism of Action: Fondaparinux, a synthetic pentasaccharide, acts as a selective inhibitor of activated factor X. It works by binding selectively to antithrombin III and potentiates the neutralisation of factor Xa. This will interrupt the blood coagulation cascade and inhibit both thrombin formation and thrombus development. Pharmacokinetics: Absorption: Rapidly and completely absorbed. Bioavailability: 100%. Time to peak plasma concentration: 2-3 hr. Distribution: Volume of distribution: 7-11 L. Plasma protein binding: ≥94% (mainly to antithrombin III). Excretion: Via urine (64-77% as unchanged drug). Elimination half-life: 17-21 hr.
Anon. Fondaparinux. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 15/08/2014.Arixtra Injection, Ssolution (GlaxoSmithkline LLC). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed/. Accessed 15/08/2014.Buckingham R (ed). Fondaparinux Sodium. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 15/08/2014.McEvoy GK, Snow EK, Miller J et al (eds). Fondaparinux Sodium. AHFS Drug Information (AHFS DI) [online]. American Society of Health-System Pharmacists (ASHP). https://www.medicinescomplete.com. Accessed 15/08/2014.