Effect of urokinase and defibrase on coagulant system and the mechanism of urokinase-induced hemorrhage in dogs

Effect of urokinase（500,000IU）and defibrase（0.25u/kg）on coagulant system was studied in experimental dogs,and the mechanism of urokinase-induced hemorrhage was proposed.The coagulation analyses demonstrated a remarkable influence on coagulant system and activation of the fibrinolytic system with a statistically significance（p＜0.01）decrease of fibrinogen in both groups of dogs.The effect of urokinase is faster and relatively stronger and that of defibrase is longer. Depletion of serum factors Ⅱ,Ⅶ,Ⅷ,Ⅹ was shown with urokinase but not with defibrase in this study.This change probably is the mechanism of urokinase-induced hemorrhage and explains why hemorrhagical side effect is rare with defibrase.We conclude that the fibrinolytic effect is approximately similar with both urokinase and defibrase,but that of the latter is much safer and can be more wildly used in the clinical practice.For urokinase,some precaution and haematological mornitoring are required to avoid bleeding.We suggest that when urokinase-induced hemorrhage occurs it might be better to correct it by the supplementary use of coagulant factors.