Fondaparinux (Arixtra - Organon Sanofi-Synthelabo), a synthetic analog of heparin, has been approved by the FDA for prevention of deep vein thrombosis (DVT) after hip fracture surgery or knee or hip replacement.

A reader has asked us to review the choice of drugs for heparin-induced thrombocytopenia (HIT), a prothrombotic state with high morbidity and mortality. Three recent publications have made somewhat different recommendations on its treatment.

Major orthopedic surgery creates a prothrombotic state by causing tissue injury during the operation and requiring relative immobilization during recovery. Without thromboprophylaxis, 40-60% of patients undergoing major knee or hip surgery develop venographically detectable deep vein thrombosis (DVT) and 1 in 300 undergoing total hip replacement will have a symptomatic pulmonary embolism (PE). Thromboprophylaxis reduces the incidence of venous thromboembolism (VTE), but it also can cause bleeding. New guidelines for prevention of VTE have recently been published.

The injectable direct thrombin inhibitor desirudin (Iprivask – Canyon), a recombinant analog of hirudin, the leech anticoagulant protein, was approved by the FDA in 2003 for prevention of venous thromboembolism (VTE) after elective hip arthroplasty, but was only marketed recently in the US. It has been available in Europe as Revasc for about 10 years. Two other hirudin analogs are available in the US: lepirudin (Refludan) for treatment of heparin-induced thrombocytopenia (HIT) and bivalirudin (Angiomax) for use in percutaneous coronary intervention (PCI).

The FDA has approved betrixaban (Bevyxxa – Portola), a once-daily, oral, direct factor Xa inhibitor, for prophylaxis of venous thromboembolism (VTE) in adults hospitalized for an acute medical illness who have moderately or severely restricted mobility and other risk factors for VTE. Betrixaban is the first oral anticoagulant to be approved in the US for this indication.

View the Comparison Table: Some Parenteral Anticoagulants for VTE

Anticoagulants are the drugs of choice for treatment and prevention of deep venous thrombosis (DVT) and pulmonary embolism (PE), collectively referred to as venous thromboembolism (VTE). US guidelines for treatment of VTE were updated in 2020 and 2021.

Coagulation factor Xa (recombinant), inactivated-zhzo (andexanet alfa; Andexxa – Portola) has received accelerated approval from the FDA for urgent reversal of the anticoagulant effect of the direct factor Xa inhibitors apixaban (Eliquis) and rivaroxaban (Xarelto). Andexanet alfa is the second antidote for a direct oral anticoagulant to become available in the US, and the fi rst for factor Xa inhibitors. Idarucizumab (Praxbind) was approved in 2015 for reversal of the anticoagulant effect of the direct thrombin inhibitor dabigatran etexilate (Pradaxa). Andexanet alfa has not...

Antiplatelet drugs are the drugs of choice for prevention and treatment of arterial thrombosis. Anticoagulants are the drugs of choice for prevention and treatment of venous thromboembolism and for prevention of cardioembolic events in patients with atrial fibrillation.

The FDA has approved rivaroxaban (Xarelto – Janssen), an oral direct factor Xa inhibitor, for prevention of deep vein thrombosis (DVT) in patients undergoing knee or hip replacement surgery.