Abstract

Since we reviewed ancrod (Arvin - Berk) 5 years ago¹ it has been marketed and the reported indications for its use have widened. Ancrod is the partly purified fraction of the venom of the Malayan pit viper (Agkistrodon rhodostoma). The drug produces its anticoagulant effect by converting plasma fibrinogen into an unstable form of fibrin which is then rapidly removed from the circulation. This defibrination reduces the concentration of circulating fibrinogen without producing vascular occlusion. Ancrod does not seem to affect the other clotting factors directly but the high level of fibrin degradation products during the induction period may transiently impair platelet function. Fibrinogen depletion might be useful in the treatment of venous thrombo-embolism; loss of fibrinogen also reduces blood viscosity and may help in a variety of conditions, for example in peripheral arterial insufficiency.