Recent reports * have indicated that therapeutic hypoprothrombinemia may be produced and maintained safely and effectively by the administration of the 4-hydroxycoumarin compound, warfarin sodium.† The rapidity of onset and duration of action of warfarin sodium has suggested that perhaps in instances where prolonged anticoagulant therapy is anticipated warfarin sodium could be administered with less frequency in somewhat larger doses, obviating the necessity for a daily prothrombin determination. This would appear to be a distinct advantage if, after a period of careful observation, a dose could be administered every three or four days that might be predicted with a reasonable degree of accuracy to maintain the prothrombin concentration in an acceptable therapeutic range. Concomitant with good predictability a lessening of the frequency for prothrombin determinations would be realized, with resultant economy.
Our clinical studies were directed by this premise, and presentation of these observations is given, together with a comparison of
CLATANOFF DV, MEYER OO. Further Observations on Use of Warfarin Sodium in Anticoagulant Therapy. AMA Arch Intern Med. 1956;97(6):753-757. doi:10.1001/archinte.1956.00250240105009