Alexandre González-Rodríguez, Rosa Catalán, Rafael Penadés, Clemente Garcia-Rizo, Miquel Bioque, Eduard Parellada, Miquel Bernardo

Short-term studies focused on once-monthly paliperidone palmitate (PP) at doses of 25 mg eq, 50 mg eq, 75 mg eq, 100 mg eq, or 150 mg eq have shown its efficacy and tolerability in the treatment of schizophrenia patients. However, few open-label and long-term studies are available regarding this new pharmacological formulation. Thus, our main aim was to review the scientific evidence on efficacy, safety, tolerability, and preference of PP in these populations. Electronic searches were conducted by using PubMed and ISI Web of Knowledge databases. All relevant studies published from 2009 until January 2015 were included without any language restriction if patients met diagnostic criteria for schizophrenia, and adequate information on efficacy, safety, and tolerability of once-monthly PP was available. Nineteen studies were identified irrespective of the study design and duration of the follow-up period. Randomized, double-blind, placebo-controlled trials found that schizophrenia patients receiving PP showed a significant improvement in psychotic symptoms and similar adverse events compared to placebo and suggested that all doses of PP were efficacious and well tolerated. Other studies demonstrated noninferiority of PP compared to risperidone long-acting injectable in recently diagnosed schizophrenia patients, chronically ill patients, as well as in acute and nonacute symptomatic schizophrenia patients, and a similar proportion of treatment-emergent adverse events between both groups were also noted. Several studies have demonstrated that schizophrenia patients treated with PP show higher rates of improvement of psychotic symptoms compared to placebo, and similar efficacy and tolerability outcomes were noted when comparing PP to risperidone long-acting injectable or oral, paliperidone extended release.