[Influence of cation dyes on blood coagulation]

Experiments on rabbits showed that intravenous injection of dyestuffs of the thionine series (toluidine blue, azur A, 1:9 dimethylene blue) was accompanied by hypofibrinogenemia, a decrease in the concentration of prothrombin complex factors, thrombocytopenia and the lowering of the blood platelets adhesion against the background of delayed blood thrombogenesis. The blood heparin tolerance and the amount of free heparin were sharply lowered. The authors consider that the hypocoagulative effect of cationic dyestuffs on the blood was caused by the thrombocytopenia and by the lowering of the platelet aggregation activity.