THE EFFECT OF DICUMAROL (3,3'-METHYLENEBIS [4-HYDROXYCOUMARIN]) ON PLATELET ADHESIVENESS

Abstract

Spooner and Meyer report, using a method described by H. P. Wright in 1941, that the adm. of Dicumarol an in vivo anti-coagulant having no in vitro action causes a decrease in platelet adhesiveness. Dicumarol was given to each of 33 patients for a period of 6 days and in dosage so that the prothrombin time was reduced from a control level of 10-12 secs, to between 20 and 30 secs. Platelet counts were done at 20 min. intervals while rotating the blood samples in a chamber and the fall in platelets was a measure of the rate and degree of platelet adhesiveness to the glass. The decrease in platelets was much less and to a degree significant statistically when Dicumarol had been administered than when it had not been. In general, the greatest decrease in platelet adhesiveness corresponded to the greatest prolongation of prothrombin time. The drug caused no change in the platelet count per se. The data presented constitute additional evidence in favor of Dicumarol as a prophylactic agent of thrombosis.