• Mechanism of Action
• Binds to and activates antithrombin III, which as a heparin-ATIII complex inactivates factor Xa
• • Pharmacology
  • More potent (2-4x) than unfractionated heparin due to higher activation of antithrombin III
  • Smaller molecules are able to bind primarily to factor Xa, with little effect on IIa
  • Better bioavailability and more predictable response than heparin
  • Effective half-life is 4 hours.
  • Reversed with protamine sulfate, though less effectively than with unfractionated heparin)

Clinical Use

• • Indications
  • Prevention of venous thromboembolism (DVT / PE)
  • Treatment of venous thromboembolism (DVT / PE)
  • ST elevation myocardial infarction (STEMI)
  • Bridging anticoagulation for initiation / withholding of warfarin
  • Prevention of thrombosis during haemodialysis
  • Acute limb ischaemia (unfractionated heparin)
• • Adverse Effects
  • Haemorrhage
  • Hypersensitivity
  • Elevated LFTs
  • Thrombocytopaenia (less commonly than heparin)
• • Monitoring
  • Not monitored in most cases, though anti-factor Xa levels may be taken.