Fondaparinux is a drug that is approved by the FDA for the treatment of blood clots in deep veins and in the lungs. Fondaparinux is not FDA approved for the treatment of HIT. However, an increasing number of doctors are using fondaparinux instead of DTIs to treat HIT. Although fondaparinux appears to be more convenient and predictable than DTI medications, more research is needed to support its use as a treatment for HIT.