Antihemophilic factor inhibitors. Management with prothrombin complex concentrates.

Prothrombin complex concentrates have been evaluated in the treatment of acute bleeding episodes occurring in 11 hemophilic and two nonhemophilic patients with factor VIII inhibitors. In several of the hemophilic patients, a continued fall in inhibitor levels has been observed coincident with continued use of the concentrate Proplex, and one of these patients is now responsive to factor VIII therapy. The therapeutic effectiveness of prothrombin complex products appears to be related to the presence of small amounts of activated factors or to the continued formation of factor Xa in vivo as a result of the increased levels of prothrombin and factors VII and X. Until high-potency activated products are available, prothrombin concentrates offer an effective means of treating patients with factor VIII inhibitor.