Fondaparinux

Indications

Fondaparinux is used for: Venous thromboembolic events, acute DVT, pulmonary embolism (PE), unstable angina or non-ST segment elevation MI

Adult Dose

Deep Vein Thrombosis/Acute Pulmonary Embolism Treatment <50 kg: 5 mg SC once daily 50-100 kg: 7.5 mg SC once daily >100 kg: 10 mg SC once daily Administer for 5-9 days; up to 26 days administered in clinical trials Prophylaxis >50 kg: 2.5 mg SC once daily for 5-9 days or up to 10 days following abdomonal surgery; for hip replacement, 11 days recommended and a minimum 10-14 days recommended for patients undergoing total hip or knee arthroplasty, or hip fracture surgery; administered for up to 35 days in some instances

Child Dose

Safety and efficacy not established

Renal Dose

Renal impairment: CrCl (ml/min) Dosage Recommendation <20 Contraindicated. 20-50 1.5 mg once daily.

Administration

Administration Administer initial dose 6-8 hours after surgery, once hemostasis has been established SC administration is deep, alternating right and left anterior and posterior abdominal walls

Contra Indications

Hypersensitivity. Active clinically significant bleeding, acute bacterial endocarditis.

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. Monitoring Parameters Monitor CBC, platelet count, serum creatinine and stool occult blood regularly. Lactation: Unknown whether drug is excreted in milk; use with caution

Pregnancy-Lactation

Interactions

Increased risk of bleeding w/ (e.g. desirudin, fibrinolytic drugs, glycoprotein IIb/IIIa-receptor antagonists, heparin, heparinoids or LMWH).

Adverse Effects

Side effects of Fondaparinux : >10% Anemia (1-20%),Fever (4-14%),Nausea (3-11%) 1-10% Rash (7.5%),Dizziness (4%),Confusion (3%),Constipation (5-9%),Diarrhea (2-3%),Edema (9%),Headache (2-5%),Hypokalemia (1-4%),Hypotension (4%),Insomnia (4-5%),Purpura (4%),Thrombocytopenia (3%),Urinary retention (3%),Urinary tract infection (2-4%),Vomiting (1-6%)

Mechanism of Action

Fondaparinux, a synthetic pentasaccharide, acts as a selective inhibitor of activated factor X. It works by binding selectively to ATIII, and potentiates the neutralisation of Factor Xa. This will interrupt the blood coagulation cascade and inhibit both thrombin formation and thrombus development. At the recommended dosage, fondaparinux does not affect fibrinolytic activity or platelet function. It cannot lyse established thrombi and does not affect clotting function tests (e.g. aPPT, INR).