Evaluating Prescribing Practices of Apixaban in the Elderly

OBJECTIVE: The aim of this study was to evaluate prescribing practices for elderly patients started on apixaban in multiple practice settings.<br/> DESIGN: Retrospective, chart review.<br/> SETTING: One outpatient and three inpatient settings in Arizona and Massachusetts.<br/> PATIENT, PARTICIPANTS: Patients who received a new order for apixaban between July 1, 2015, and December 31, 2016. Inclusion criteria included adults 65 years of age and older who were receiving apixaban for atrial fibrillation or venous thromboembolism (VTE) at a current treatment dose.<br/> There were 1,045 patients included, the average age was 78 years, 52% were male, and 90% had atrial fibrillation.<br/> MAIN OUTCOME MEASURE: Appropriate prescribing of apixaban based on Food and Drug Administration (FDA)-labeling (age, weight, serum creatinine).<br/> RESULTS: Six patients who were on hemodialysis were excluded from the analysis, leaving 1,039 patients to be analyzed. 16.2% (168/1,039) of patients had an incorrect dose of apixaban prescribed based on their indication. Of those, 75% (126/168) were taking the medication for atrial fibrillation and 25% (42/168) for VTE. For those with atrial fibrillation (n = 126), the majority of inappropriate orders resulted from doses that were lower than indicated (113/126).<br/> CONCLUSION: This research suggests that elderly patients may receive inappropriately lower doses of apixaban than indicated, which may decrease the effectiveness of the medication. This research supports the fact that pharmacists can play a vital role in anticoagulation stewardship by verifying apixaban doses for accuracy.