Raloxifene Users Research Articles

Effects of raloxifene therapy on the anticoagulant system in postmenopausal women

Background: Raloxifene therapy is associated with a three-fold increase in the risk for venous thromboembolism; however, its effects on the hemostatic system in postmenopausal women have not beenwell defined.Objective: To determine the effects of raloxifene therapy on the levels of natural anticoagulant proteins in postmenopausal women.Methods: Sixteen healthy postmenopausalwomen were enrolled in this prospective longitudinal study. The patients were treated with raloxifene hydrochloride (60 mg/day) for a period of 6 months. Antithrombin and protein C activities and proteinS antigen levels were measured in all users at baseline, and after 1, 3 and 6 months of treatment. Statistical analysis included one-way analysis of variance (ANOVA) and the Bonferroni test for multiplecomparisons among the study periods.Results: Statistically significant 5.1% and 6.5% reductions of plasma antithrombin activity were observed at 3 and 6 months of therapy, respectively (p< 0.05). Compared with baseline, raloxifene did not significantly affect protein C activity or protein S level.Conclusions: The results of this prospective study show for the first timethat raloxifene use is associated with a significant reduction in plasma antithrombin activity. This effect may contribute to a procoagulant state and partly explain the increased risk of venous thromboembolismin raloxifene users.