Danaparoid, a heparinoid with predominantly anti-Xa activity and some anti-IIa activity, is a mixture of three glycosaminoglycans (heparin sulfate, dermatan sulfate, and chondroitin sulfate) that exerts its anticoagulant effect by catalyzing the inactivation of factor Xa in the presence of antithrombin. It has a unique property of specific suppression of HIT antibody-induced platelet activation that is not observed with other drugs used for HIT treatment.101 Danaparoid has a low cross-reactivity rate with HIT antibodies in vitro but very rarely in vivo. It was withdrawn from US markets in 2002, but use of the drug to treat HIT has been approved in many European countries and some countries outside Europe (eg, Canada, Australia, New Zealand, and South Africa). For the treatment of HIT, danaparoid is given IV according to the following dosing regimen: a bolus of 2,250 units, followed by an infusion of 400 units/h for 4 h, 300 units/h for 4 h, and then 200 units/h for at least 5 days, or longer if clinically appropriate. After the initial period, the danaparoid infusion rate is adjusted to maintain a plasma anti-Xa level between 0.5 and 0.8 anti-Xa units/mL (performed with a danaparoid standard curve).102 However, significantly fewer major bleeding episodes were recorded97 in those patients treated with danaparoid compared with those treated with lepirudin.