Dicumarol: Its action, clinical use and effectiveness as an anticoagulant drug

Abstract

Dicumarol is a potent and valuable anticoagulant drug. When used properly it appears to prevent intravascular thrombosis in almost all patients. There is considerable and unpredictable variation in sensitivity to dicumarol among different patients. Dosage of dicumarol must be guided by the effect produced in each patient as indicated by the degree and duration of prothrombin deficiency which develops and is indicated by determinations of the concentration of prothrombin in the blood. It is unwise to use dicumarol unless adequate facilities for determining the prothrombin time are available. If the prothrombin is kept between 10 and 30 per cent of normal by administration of dicumarol, thrombosis will almost certainly be prevented and serious bleeding is very unlikely to occur. The action of dicumarol is delayed. When a rapid anticoagulant effect is desired concurrent heparinization is necessary for the first few days. We have found that dicumarol has prevented fatal pulmonary embolism and recurrence or extension of venous thrombosis in patients who have had postoperative nonfatal pulmonary embolism or thrombophlebitis. There is some incomplete evidence to the effect that it will prevent peripheral thrombosis, pulmonary embolism and further coronary thrombosis in patients who have had acute myocardial infarction. Dicumarol with preliminary heparinization is valuable in the treatment of acute arterial occlusion of the extremities. It has also been used safely in patients in whom thrombophlebitis and pulmonary embolism complicated the puerperium and various diseases, in patients with idiopathic recurrent thrombophlebitis and in those with chronic occlusive arterial disease. While statistical confirmation is lacking, it is our impression that in many of these patients thrombosis and embolism have been prevented by administration of dicumarol.