Aripiprazole: a new atypical antipsychotic with a different pharmacological mechanism

Aripiprazole is a new atypical antipsychotic with a mode of action that is distinct from currently available antipsychotic drugs. In phase III comparative clinical studies, aripiprazole 15-30 mg/day was at least as effective as haloperidol and risperidone in short term treatment of acute exacerbation of schizophrenia but superior to haloperidol in long term maintenance therapy. Consistent with an atypical profile, aripiprazole is effective against positive, negative and cognitive symptoms of schizophrenia and has a favourable side effect profile with the incidence of extrapyramidal symptoms (EPS) comparable to placebo. It is also devoid of side effects such as clinically significant hyperprolactinaemia, hypercholesterolaemia and cardiotoxicity, and has a low propensity for weight gain. Symptom relief is achieved without significant sedation. These clinical data suggest its usefulness in psychosocial rehabilitation, as well as in long-term prevention of schizophrenic relapse. Recent results from a multicentre, open-label study in a general psychiatric setting provide the first evidence that aripiprazole is also effective under naturalistic conditions. However, only post-marketing experience will show whether the positive results of these controlled trials can be replicated in everyday practice.