What is the recommended dosing for Fondaparinux (Pentasaccharide) in the treatment of Heparin-Induced Thrombocytopenia (HIT)?

Fondaparinux Dosing for Heparin-Induced Thrombocytopenia (HIT)

For patients with HIT, fondaparinux should be dosed according to weight: 5 mg subcutaneously once daily for patients <50 kg, 7.5 mg subcutaneously once daily for patients 50-100 kg, and 10 mg subcutaneously once daily for patients >100 kg. 1

Evidence-Based Dosing Recommendations

The dosing of fondaparinux for HIT is weight-based and follows the therapeutic anticoagulation dosing strategy:

• <50 kg: 5 mg subcutaneously once daily 1
• 50-100 kg: 7.5 mg subcutaneously once daily 1
• >100 kg: 10 mg subcutaneously once daily 1

Efficacy and Safety Profile

• Fondaparinux has demonstrated comparable efficacy to direct thrombin inhibitors (DTIs) in the treatment of HIT:

  • Similar rates of thrombosis resolution 2
  • Complete platelet count recovery in clinical studies 2
  • Lower bleeding rates compared to lepirudin (4.2% vs 10%) 1

• A propensity score-matched study showed fondaparinux had similar effectiveness and safety compared to argatroban and danaparoid in patients with suspected HIT 3

Special Considerations

Renal Function

• While fondaparinux is primarily renally cleared, it has been used successfully in patients with renal impairment 4, 5
• For patients with severe renal impairment:
  • Consider dose reduction and close monitoring 4
  • Note that the ACCP guidelines suggest argatroban as the preferred agent for patients with renal insufficiency 1

Prophylactic vs. Therapeutic Dosing

• For patients with HIT without thrombosis who require only prophylactic anticoagulation, lower prophylactic doses may be considered 3
• For patients with confirmed thrombosis (HITT), full therapeutic dosing as outlined above is required 1

Important Clinical Considerations

• Fondaparinux is not FDA-approved for HIT treatment, though clinical evidence supports its use 6
• The ACCP guidelines suggest argatroban, lepirudin, or danaparoid over other non-heparin anticoagulants for HIT with normal renal function (Grade 2C) 1
• However, fondaparinux may be considered when these agents are unavailable or contraindicated 6, 4
• Monitor platelet counts closely to ensure recovery after initiating fondaparinux 2
• Do not initiate warfarin until platelet count has recovered and the patient is adequately anticoagulated 6

Monitoring

• No specific laboratory monitoring is required for fondaparinux, unlike argatroban or lepirudin which require aPTT monitoring 6
• Regular monitoring of platelet counts is essential to confirm recovery 2
• Anti-Xa monitoring is generally not required but may be considered in patients with renal impairment 4