Selective Factor Xa Inhibitor (Synthetic Pentasaccharide)

Fondaparinux Sodium

Brand names: Arixtra

Fondaparinux is a synthetic factor Xa inhibitor given by subcutaneous injection for venous thromboembolism prophylaxis and treatment and in acute coronary syndromes.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It binds antithrombin to selectively inhibit factor Xa; unlike heparins it does not cross-react in heparin-induced thrombocytopenia.

Prescribing in practice

It is renally cleared — avoid in severe renal impairment and reduce/monitor in moderate impairment.
It does not cause heparin-induced thrombocytopenia, so it is an option where that is a concern.
Observe timing around neuraxial procedures.

Monitoring

Monitor renal function; routine coagulation monitoring is not required.

Counselling the patient

It is given as an injection under the skin.
Report unusual bleeding or bruising.

Evidence & guidelines

Used for VTE prophylaxis/treatment and in ACS, and as an option where heparin-induced thrombocytopenia is a concern.

Reference: NICE guidelines; OASIS-5 trial; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways