Studies on the Anticoagulant Action of Aprotinin (“Trasylol”)^[*]

Summary

Studies were undertaken to localize the site of the anticoagulant action of Aprotinin (“Trasylol”). Contact activation studies using either kaolin or contact product eluted from celite demonstrated that Aprotinin had greatest inhibitory action against the interaction of a surface with the contact factors, but some inhibition of formed contact product was also noted. In addition, Aprotinin was found to have a slight anticoagulant action against activated factor IX prepared by incubation of contact product with a calcium phosphate eluate from serum. No inhibitory action in pharmacological doses was demonstrated against activated factor X or later stages in the coagulation sequence.

It was concluded that Aprotinin is a relatively weak anticoagulant in doses liable to be obtained in vivo during therapeutic infusions.

^* The work conducted by C.R. M. Prentice has been supported by a grant from the Medical Research Council.

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