Evaluation of Laboratory Changes During Long-Term Anticoagulant Use

Abstract

As is often the case in medicine, the use of oral anticoagulants began by chance. The history of their discovery is associated with the diagnosis of an unusual hemorrhagic diathesis observed in cattle in North America and Canada in the early twentieth century. In the 1920s, studies emerged attributing this disease to prothrombin deficiency in the blood [1], which developed when cattle consumed spoiled hay [2]. An accurate diagnosis became possible only after A. Quick developed a method for determining prothrombin time in 1935 [3]. The results of this test demonstrated that fatal bleeding in animals was caused by a deficiency of prothrombin complex factors. The toxic substance isolated from spoiled hay was characterized as 4-hydroxycoumarin and named "dicumarol."