Evaluation of Dosing Practices of Rivaroxaban and Dabigatran.

Abstract

Background: Anticoagulation is standard practice for the prevention and treatment of thromboembolic events. Two of the newer agents, rivaroxaban (Xarelto) and dabigatran (Pradaxa) are being utilized frequently in the inpatient and outpatient settings. Prescribers may not appreciate the need for dose reduction in the setting of renal insufficiency. Objective: The objective of this study was to evaluate whether rivaroxaban and dabigatran were dosed according to recommendations in the package insert for patients with renal insufficiency. Methods: Eligible patients were those >18 years of age who received rivaroxaban or dabigatran as an inpatient or had a prescription filled from the outpatient pharmacy. The use of the Cockcroft-Gault equation was utilized to calculate creatinine clearance to evaluate whether patients had appropriate manufacturer recommended dose reductions based on their renal function. Results: There were very few patients (8 of 355, or 2.3%) who should have received a reduced dose when creatinine clearance was calculated utilizing actual body weight. In those patients with renal insufficiency, 3 of 6 (50.0%) patients receiving rivaroxaban and 1 of 2 (50%) patients receiving dabigatran were appropriately dosed. When ideal body weight was substituted for creatinine clearance calculation, there were 15 patients receiving rivaroxaban and 10 patients receiving dabigatran who fell below the creatinine clearance threshold for dose reduction. Conclusions: Based on this evaluation, very few patients required a dose reduction due to renal insufficiency. It is important for clinicians to always monitor renal function when utilizing these medications to optimize the benefits of the new oral anticoagulants while limiting potential deleterious effects. Furthermore, it is necessary to ensure that actual body weight is being utilized for creatinine clearance calculations with the new oral anticoagulants and not to base dosing on estimated glomerular filtration rate or other calculated creatinine clearance as this could lead to inappropriate dose reductions.