Effectiveness of switching from long-acting injectable fluphenazine or haloperidol decanoate to long-acting injectable risperidone microspheres: An open-label, randomized controlled trial

Objective: This multisite randomized trial addressed risks and benefits of staying on long-acting injectable haloperidol or fluphenazine versus switching to long-acting injectable risperidone microspheres. Method: From December 2004 through March 2008, adult outpatients with a Structured Clinical Interview for DSM-IV Axis I Disorders-Patient Edition diagnosis of schizophrenia or schizoaffective disorder who were taking haloperidol decanoate (n = 40) or fluphenazine decanoate (n = 22) were randomly assigned to stay on current long-acting injectable medication or switch to risperidone microspheres and followed for 6 months under study protocol and an additional 6 months naturalistic follow-up. Kaplan-Meier and Cox regression analyses were used to examine the primary outcome (time to treatment discontinuation), and random regression models were used to examine secondary outcomes. Results: Groups did not differ significantly in time to treatment discontinuation through 6 months of protocol-driven treatment. When the 6-month naturalistic follow-up period was included, time to treatment discontinuation was significantly shorter for individuals assigned to switch than for individuals assigned to stay (10% of stayers discontinued versus 31% of switchers; P = .01). Groups did not differ with respect to psychopathology, hospitalizations, sexual side effects, new-onset tardive dyskinesia, or new-onset extrapyramidal symptoms. However, those randomized to switch to long-acting injectable risperidone microspheres had greater increases in body mass (increase of 1.0 body mass index [BMI] versus decrease of -0.3 BMI; P = .00) and prolactin (maximum increase to 23.4 ng/mL versus decrease to 15.2 ng/mL, P = .01) compared to those randomized to stay. Conclusion: Switching from haloperidol decanoate or fluphenazine decanoate to risperidone microspheres resulted in more frequent treatment discontinuation as well as significant weight gain and increases in prolactin.