Blood loss and tranexamic acid re-dosing after cesarean delivery

Introduction: The objective of this analysis is to determine the need for administering subsequent doses based on the magnitude of blood loss in the setting of postpartum hemorrhage after cesarean delivery by assessing the relationship between the amount of blood loss and the pharmacokinetics of tranexamic acid. Materials and methods: Data from four clinical trials were obtained, including estimates of drug clearance and volume of distribution, which were compared with recorded volume of blood loss. The time above a target concentration of 10 mg/l was simulated for each individual and compared to volume of blood loss. A multivariate analysis was conducted to assess the independent contribution of blood loss volume on drug clearance, accounting for body weight. Blood loss was analyzed both as a continuous variable and stratified into categories of clinical severity. Results: A total of 207 individuals were categorized based on intraprocedural volume of blood lost, ranging from 160 ml to 10 l. A weak, positive correlation was found between drug clearance and blood loss volume, with a small effect size relative to the residual error estimate that implied that though statistically significant, the impact on clearance may not be clinically notable. Conclusions: The analysis concluded that blood loss does not greatly affect the pharmacokinetic disposition of tranexamic acid; therefore, there may be no need to base tranexamic acid re-dosing frequency on the amount of blood loss in cases of mild to moderate hemorrhage volumes.