What is the dosage of Fondaparinux (pentasaccharide anticoagulant) for Deep Vein Thrombosis (DVT) prevention and treatment?

Fondaparinux Dosage for DVT Prevention and Treatment

For DVT prevention, fondaparinux is administered at 2.5 mg subcutaneously once daily, while for DVT treatment, the dose is weight-based: 5 mg (<50 kg), 7.5 mg (50-100 kg), or 10 mg (>100 kg) subcutaneously once daily. 1

Prevention of DVT

Dosage

• Standard prophylactic dose: 2.5 mg subcutaneously once daily 1
• Timing: Initial dose should be given no earlier than 6-8 hours after surgery (after hemostasis has been established) 1
• Duration:
  • General surgery/orthopedic surgery: 5-9 days 1
  • Hip fracture surgery: Extended prophylaxis up to 24 additional days (total of 32 days) is recommended 1

Special Populations

• Renal impairment:
  • Fondaparinux is contraindicated in severe renal impairment (CrCl <30 mL/min) for prophylaxis 1
  • For moderate renal impairment (CrCl 20-50 mL/min), a reduced dose of 1.5 mg once daily may be appropriate 2
• Weight considerations:
  • Contraindicated in patients weighing <50 kg for prophylaxis due to increased bleeding risk 1

Treatment of DVT/PE

Dosage

• Weight-based dosing 1:
  • <50 kg: 5 mg subcutaneously once daily
  • 50-100 kg: 7.5 mg subcutaneously once daily

  • 100 kg: 10 mg subcutaneously once daily

Duration

• Continue for at least 5 days and until therapeutic oral anticoagulant effect is established (INR 2-3) with warfarin 1
• Usual duration is 5-9 days (up to 26 days was administered in clinical trials) 1
• Initiate warfarin as soon as possible, usually within 72 hours 1

Special Populations

• Renal impairment: Contraindicated in severe renal impairment (CrCl <30 mL/min) for treatment 1
• Obese patients: For patients >100 kg, the treatment dose should be increased to 10 mg daily 3, 1

Clinical Considerations

Efficacy

• Fondaparinux has demonstrated superior efficacy compared to enoxaparin for VTE prevention in orthopedic surgery, with >50% risk reduction 4
• For DVT treatment, fondaparinux has shown similar efficacy to enoxaparin with recurrent VTE rates of 3.9% vs 4.1% 5

Safety Considerations

• Major bleeding risk may be higher with fondaparinux compared to enoxaparin in orthopedic surgery patients 4
• Avoid use in patients with:
  • Severe renal impairment (CrCl <30 mL/min)
  • Active major bleeding
  • Bacterial endocarditis
  • Thrombocytopenia with positive anti-platelet antibody test
  • History of serious hypersensitivity reactions to fondaparinux 1

Administration

• Administer subcutaneously only (not intramuscularly) 1
• Do not mix with other injections or infusions 1
• Alternate injection sites between the left and right anterolateral or posterolateral abdominal wall 1

Common Pitfalls

• Administering fondaparinux too early after surgery (before 6 hours) increases bleeding risk 1
• Using fondaparinux in patients with severe renal impairment can lead to drug accumulation and bleeding 1
• Failure to adjust dose based on body weight for treatment (but not for prophylaxis) 1
• Not monitoring for signs of bleeding, especially in high-risk patients 1
• Using fondaparinux in patients weighing <50 kg for prophylaxis 1

For patients requiring an alternative to heparin or LMWH, fondaparinux offers an effective option with a predictable anticoagulant response and no need for routine monitoring in most patients.