Aug 16 2012
By Piriya Mahendra, MedWire Reporter
Laboratory tests show no significant differences in rivaroxaban efficacy across children aged from 28 days to 16 years, researchers report.
"Given the differences observed during in vitro testing with other commonly used anticoagulants, this is important and suggests that rivaroxaban may be a useful anticoagulant," write Vera Ignjatovic (Murdoch Children's Research Institute, Victoria, Australia) and team in Thrombosis Research.
This is because rivaroxaban's "anticoagulant effect may be more predictable across the spectrum of pediatric age ranges," they explain.
The study findings showed that rivaroxaban had no age-related effect in multiple automated prothrombin time, activated partial thromboplastin time (APTT), and anti-factor Xa monitoring assays.
Furthermore, measured parameters of thrombin generation including endogenous thrombin potential, lag time, time to peak, and peak free thrombin were not affected by rivaroxaban in an age-dependent manner for APTT, nor tissue factor-activated thrombin generation assays.
For the study, the researchers created age-specific plasma pools: 28 days-23 months, 2-6, 7-11, 12-16 years, and adults (>18 years). Each pool was spiked with six different concentrations of rivaroxaban (25-500 ng/mL).
The authors say additional studies in neonates are required to determine if there are any specific differences in this age group.
"However the prospect of an anticoagulant that has an equivocal measurable effect across the age ranges of children is most attractive because it makes dosing schedules much simpler," they say.
The authors add that the results of this study, paired with rivaroxaban's oral bioavailability, once-daily dosing, and limited need for monitoring, indicate that the drug is an ideal anticoagulant for use in children, subject to clinical studies.
"Dosing of the drug must be adjusted for physiological differences in, for example, absorption, metabolism, and elimination across the age spectrum of children," Ignjatovic and colleagues conclude.
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