Risperidone Long-Acting Injectable Monotherapy in the Maintenance Treatment of Bipolar I Disorder

Background Treatment adherence is a significant problem in patients with bipolar disorder. This study was designed to determine the efficacy of risperidone long-acting injectable (LAI) in the maintenance treatment of bipolar I disorder. Methods Eligible patients with current or recent manic or mixed episodes ( n = 559, aged 18–65 years) were treated with open-label oral risperidone for 3 weeks (period II) and open-label risperidone LAI for 26 weeks ( n = 501; period III). Patients who maintained response ( n = 303) were randomly allocated 1:1 to placebo injections ( n = 149) or to continue risperidone LAI ( n = 154) for up to 24 months (period IV). Results Most (77%) patients on risperidone LAI received a dose of 25 mg every 2 weeks during period IV. Time to recurrence for any mood episode (primary outcome variable) was significantly longer in the risperidone LAI group versus placebo ( p p p = .805). Weight gains ≥7% (compared with the period's baseline) occurred in 15% of patients in period III; in 12% of patients on risperidone LAI and 3% of patients on placebo in period IV. Conclusions Risperidone LAI monotherapy significantly delayed the time to recurrence of mood episodes, versus placebo, in this controlled, randomized study in patients with bipolar I disorder. Risperidone LAI was tolerable and no new safety concerns emerged compared with previous studies of risperidone LAI.