Fondaparinux sodium

How it works

It binds antithrombin and accelerates antithrombin-mediated inhibition of factor Xa, interrupting the coagulation cascade without directly inhibiting thrombin.

Prescribing in practice

• It is largely renally cleared and accumulates in renal impairment, substantially increasing bleeding risk, so it is contraindicated or requires dose reduction depending on renal function and indication.
• Bleeding is the principal hazard and there is no specific reversal agent, so it should be used cautiously around surgery and neuraxial procedures because of spinal or epidural haematoma risk.
• Unlike heparin it does not usually cross-react in heparin-induced thrombocytopenia, but routine anti-Xa monitoring is not required.

Monitoring

Assess renal function and platelet count and watch for signs of bleeding rather than relying on routine coagulation monitoring.

Counselling the patient

• This is a blood-thinning injection given under the skin.
• Report unusual bruising, bleeding, black stools or blood in urine.
• Tell any clinician planning surgery or a spinal procedure that you are using it.

Evidence & guidelines

Fondaparinux is supported by landmark venous thromboembolism prophylaxis and treatment trials and is recommended in NICE acute coronary syndrome and VTE guidance.