One-year treatment continuation in patients switched to paliperidone palmitate: a retrospective study.

To the Editor: Paliperidone palmitate is a long-acting injectable (LAI) antipsychotic, approved for treatment of schizophrenia in adults.1 It is the major active metabolite of risperidone and, in its injectable form, has several potential advantages over other LAIs. It reaches steady state within 4 to 8 days, so patients are not required to take oral supplementation at initiation of therapy.2 It can be administered monthly2 and can be given up to 7 days before or after the usual date of administration, allowing flexibility to avoid missed doses.3 Given these advantages, clinicians may be inclined to switch patients from other LAIs to paliperidone palmitate. However, there are limited data on the outcome of patients switched to paliperidone palmitate over extended durations, with most studies following patients for 13 weeks or less.4–8 Of the 3 longer-term studies,9–11 2 excluded many of the patients seen in real-world practice (including involuntary patients, those with substance dependence, and those at risk of suicidal behavior).9,10 There is only 1 previously published naturalistic paliperidone palmitate switching study, and it demonstrated a discontinuation rate of 35% over 1 year.11 The aim of our study was to retrospectively follow 45 patients of a mental health service for 52 weeks after they were switched from their antipsychotic to paliperidone palmitate and to explore risk factors for discontinuing the treatment. Understanding these factors may help clinicians to more appropriately select patients for treatment with paliperidone palmitate.