Robin Emsley, Sanja Kilian

The course of schizophrenia is characterized by multiple relapses, incomplete remission of symptoms, enduring cognitive deficits, and social and occupational functional impairments. Nonadherence to antipsychotic medication is a major determinant of this poor outcome. Long-acting injectable antipsychotics were developed specifically to address the nonadherence problem and are increasingly considered as an early treatment option, in an attempt to prevent accruing morbidity. This review focuses on paliperidone palmitate, the long-acting injectable (LAI) formulation of paliperidone. After considering the pharmacology of paliperidone palmitate, we review the randomized controlled trials, as well as pertinent observational, pragmatic studies for paliperidone once-monthly injections in schizophrenia. Finally, we review the recently introduced 3-monthly formulation of paliperidone palmitate. Taken together, the studies indicate that paliperidone palmitate (PP) has good efficacy compared with placebo and comparable with other antipsychotics including risperidone. The tolerability profile of PP is similar to that of risperidone, with the most important side effects being prolactin elevation, weight gain, and extrapyramidal symptoms. Advantages of PP include the extensive research database and clinical experience with paliperidone and its parent compound risperidone, the availability of different LAI formulations (once-monthly, 3-monthly, and perhaps even longer acting formulations in future), and the novel dose initiation procedure that provides rapid onset of action without the need for oral antipsychotic supplementation.