A Comparison of Heparin and Bishydroxycoumarin (Dicumarol) as Anticoagulants

I. Introduction Heparin and bishydroxycoumarin ( Dicumarol) have been available for clinical use as anticoagulants for about 18 years. The choice as to which to use has not always been easy. In instances where anticoagulant effect is immediately needed or in which it is required for a few days (less than four) only, heparin is the choice because of the early appearance and quick disappearance of its effect. If a long-term effect is needed over a matter of weeks, bishydroxycoumarin, or a drug with similar action, is widely used because of the disadvantages of heparin with respect to the necessity of parenteral injection and expense. The decision as to which drug to employ when the duration of therapy is to be a matter of one or two weeks, a situation which is common in the therapy of thromboembolism, is not so simple. The drug selected has generally been that with which