[Treatment with oral anticoagulants (acenocoumarol): influence of the initial doses in the incidence of hemorrhagic and thromboembolic episodes].

Purpose: To compare two initial doses of oral anticoagulant (acenocoumarin) studying the haemorrhagic and thromboembolic episodes occurred during the first month of treatment, the mean time and necessary controls until achievement of the desired level of anticoagulation.

Patients And Methods: From january 1992 to december 1993; a comparative study of two groups of patients was performed: group 1, compiling 129 patients chosen at random and retrospectively, who begun oral anticoagulant treatment with 4 daily mg of acenocoumarin; and group 2, compiling 129 patients chosen prospectively, who begun with 2 mg daily. In both groups the mean time and the number of controls performed until achieving the desired level of anticoagulation were analyzed, as well as the haemorrhagic episodes occurred during the first month of treatment, their severity (classified into major and minor ones), the level of anticoagulation when they occurred and their possible causes. In the same way the thromboembolic processes occurred during that period in both groups were studied.

Results: The mean time necessary to achieve the desired level of anticoagulation was 3.8 days in group 1 and 6.3 in group 2; the mean number of controls performed in group 1 was 1.2 and in group 2 it was 1.8. We have observed 19 haemorrhagic episodes, 15 in group 1 (4 minor and 11 major); and 4 in group 2 (2 minor and 2 major). We have found significant differences with respect to the mean time (p < 0.01), number of controls (p < 0.01) and incidence of hemorrhages (p = 0.017) between groups 1 and 2. One thromboembolic episode was registered in each group: in group 1 a deep venous thrombosis and in group 2 a stroke.

Conclusion: The initial daily doses of acenocoumarin of 2 mg is as effective as the 4 mg one in the prevention of thromboembolic episodes, with a significant reduction in the number of haemorrhages observed during the first month of treatment. However this produces a prolongation in the necessary mean time and more number of controls performed until the achievement of the desired level of anticoagulation.