Influence of heparin, protamine and polybrene on the time integral of thrombin generation (endogenous thrombin potential).

We investigated the anticoagulating and heparin-neutralizing properties of protamine and polybrene (hexadimethrine bromide), using the endogenous thrombin potential (ETP) as the parameter to access plasma coagulability. The hypocoagulability induced by high doses of heparin (3 IU/ml) could be reversed by addition of protamine to a very limited extent only. Polybrene on the other hand did neutralize heparin at the equivalent concentration and a two-fold excess did not influence the ETP parameters. In vivo neutralization of high-dose heparin with protamine should therefore be reconsidered. Our experiments suggest polybrene to be superior over protamine with respect to neutralization of high doses of heparin.