Enoxaparin (Lovenox - Rh ne-Poulenc Rorer), the first low-molecular-weight heparin to become commercially available in the USA, was recently approved by the US Food and Drug Administration for prevention of deep vein thrombosis following hip replacement. Five other products have been marketed in Europe.

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.

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 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.

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.

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).

Percutaneous coronary intervention (PCI), such as balloon angioplasty or stent placement, predisposes to subsequent thrombosis. The current pharmacologic approach to prevention of this problem combines an anticoagulant with one or more antiplatelet drugs.

View the Comparison Table: Some Parenteral Anticoagulants for VTE

Anticoagulants are the drugs of choice for treatment of deep vein thrombosis (DVT) and pulmonary embolism (PE), collectively referred to as venous thromboembolism (VTE).

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...