Aripiprazole: a new treatment for schizophrenia

Aripiprazole has a unique mechanism of action that differs from all currently available antipsychotic agents. Aripiprazole combines potent partial agonist activity at dopamine D2 receptors and serotonin (5-HT) 1A receptors, with antagonist activity at 5-HT2A receptors. In short-term clinical studies, aripiprazole produced significant improvements in Positive and Negative Syndrome Scale (PANSS) and Clinical Global Impression (CGI) Scale efficacy scores from baseline compared with placebo. These improvements were similar to those observed with haloperidol and risperidone. Aripiprazole has a rapid onset of efficacy, with improvements in PANSS total and positive subscale scores and CGI severity of illness scores seen as early as 1 week after starting treatment. Aripiprazole's efficacy is maintained in long-term treatment following acute relapse in patients with schizophrenia. In the 52-week maintenance of response study, completion and responder rates were significantly higher with aripiprazole treatment compared with haloperidol, and aripiprazole was superior to haloperidol in treating negative and associated depressive symptoms. Short-and long-term clinical studies show that aripiprazole has a low liability for extrapyramidal side effects and does not increase the risk of weight gain, hyperprolactinemia, QTc prolongation, somnolence, glucose intolerance or lipid dysregulation. Patients with schizophrenia or schizoaffective disorder can be switched safely and effectively to aripiprazole from their existing antipsychotic medication using any one of three strategies.