Post-Pyloric Administration of Rivaroxaban With Therapeutic Monitoring in Pediatric Cardiac Patients: Experience in 3 Patients.

Thromboembolism in pediatric patients with congenital heart disease (CHD) is a commonly encountered morbidity. Feeding intolerance is also commonly encountered in patients with CHD and has a direct effect on thromboembolism treatment options, as the site of gastrointestinal absorption for each agent varies. Historically, standard anticoagulation options included unfractionated heparin, enoxaparin, or vitamin K antagonists such as warfarin. Non-vitamin K oral anticoagulants, such as rivaroxaban, have become more widely used in pediatrics since obtaining Food and Drug Administration approval, but are often considered poor options for patients receiving post-pyloric enteral feeds. Adult pharmacokinetic data suggest significant variations in volume of distribution and maximum serum concentrations based on the site of administration within the gastrointestinal tract. We report 3 patients with complex CHD and significant feeding intolerance requiring therapeutic anticoagulation who successfully received rivaroxaban through a post-pyloric feeding tube. When using therapeutic serum concentration monitoring, all 4 serum concentrations were within the reported reference range, and 3 of 4 were within the age-related geometric coefficient of variation. Rivaroxaban appears to have adequate post-pyloric absorption in pediatric patients with CHD based on serum concentration monitoring.