Inhibition of the activation of Hageman factor (factor XII) by aprotinin (Trasylol)

Aprotinin (Trasylol; Bayer AG, Leverkusen, Germany), a protease inhibitor resembling or identical with Kunitz' pancreatic trypsin inhibitor, is said to have anticoagulant properties, but these are not clearly defined. The present study provides evidence that one action of aprotinin is inhibition of the activation of Hageman factor (factor XII).