Effect of oral anticoagulant (marcumar) on prothrombin and related components in blood coagulation.

Marcumar has been considered as an excellent anticoagulant for long term management. It was found that the effect of the drug on plasma levels of prothiombin and autoprothrombin I and autoprothrombin II differed from that of the drugs previously studied using the technics described. Autoprothrombin II was not reduced by Marcumar. This clotting factor, autoprothrombin II, has been found to have no influence on the Quick prothiombin time which is the test generally used to follow the effect of anticoagulants on the clotting mechanisms. The two coagulation factors which were found to decrease following the administration of Marcumar, prothrombin and autoprothrombin I, both influence the Quick prothrombin time.