Abstrait

Risperidone Long-acting Injectable versus Paliperidone Palmitate for Community-dwelling Patients with Schizophrenia

Amanda Webster, Shaun Phillips

Purpose: Studies indicate that poor medication compliance often hinders positive treatment outcomes in patients with schizophrenia. Risperidone long-acting injectable and paliperidone palmitate theoretically aid compliance as they are given only once every two or four weeks, respectively. Because the two formulations share similar pharmacologic and pharmacokinetic properties, further evaluation is required to determine whether clinically significant differences in patient outcome exist and the impact of these variations. The purpose of this study was to determine whether community-dwelling patients with schizophrenia receiving risperidone longacting injectable incur improved clinical outcomes or lowered costs than patients receiving paliperidone palmitate.

Methods: A retrospective cohort chart review was conducted on patients who had an encounter at our institution while receiving risperidone long-acting injectable or paliperidone palmitate from January 1, 2011 to December 31, 2012. The primary objective of this study was to determine the total cost of psychiatric-related care for patients receiving paliperidone palmitate versus risperidone long�acting injectable. Secondary objectives included comparisons of hospitalization days and emergency department encounters in patient-days, time to discontinuation, and time to first relapse. A subgroup analysis was conducted on patients receiving injections through a local ambulatory psychiatric facility.

Results: A total of 47 patients were included in the primary analysis with 30 patients included in the ambulatory psychiatric subgroup analysis. Risperidone long-acting injectable patients incurred lower psychiatryrelated treatment costs per patient-day than paliperidone palmitate under the total (p=0.032) and ambulatory psychiatric subgroup (p=0.049) analyses. Ambulatory psychiatric risperidone long-acting injectable patients were found to require fewer psychiatric inpatient days (p=0.044) than paliperidone palmitate patients.

Conclusion: Use of risperidone long-acting injectable was associated with significantly fewer psychiatric inpatient days and lower psychiatryrelated costs than paliperidone palmitate in our population of communitydwelling patients with schizophrenia.