Positives

• For COVID-19 patients with suspected or confirmed heparin-induced thrombocytopenia, fondaparinux is the recommended anticoagulant alternative because it does not cross-react with HIT antibodies PubMed.
  
  
• A multicenter real-world COVID-19 series found fondaparinux a workable factor Xa inhibitor option in patients who could not tolerate LMWH PMC.
  
  

Negatives

• Long COVID anticoagulation research has focused on oral apixaban combined with antiplatelets rather than parenteral fondaparinux, leaving its PASC role unstudied Medhelpclinics.
  
  

Hurdles & Side Effects

• Fondaparinux requires daily subcutaneous injection, is contraindicated in significant renal impairment, and has no specific reversal agent if bleeding occurs, limiting outpatient long-term use for non-HIT Long COVID patients Springer.