Aripiprazole.

Aripiprazole is a quinolinone derivative and the first of a new class of atypical antipsychotics. The drug has partial agonist activity at dopamine D(2) and serotonin 5-HT(1A) receptors, and is also an antagonist at 5-HT(2A) receptors. In patients with acute relapse of schizophrenia or schizoaffective disorder, aripiprazole 15 to 30 mg/day was at least as effective as haloperidol 10 mg/day and had similar efficacy to risperidone 6 mg/day in well designed, 4-week, placebo-controlled trials. Negative symptoms improved earlier in the aripiprazole than the risperidone group. Efficacy of aripiprazole was observed at week 1 in several trials and was sustained throughout the study periods. Aripiprazole was superior to placebo in a 26-week trial in patients with stable, chronic schizophrenia. In a 52-week trial involving patients with acute relapsing disease, aripiprazole was similar to haloperidol as assessed by time to failure to maintain response and was superior in ameliorating negative and depressive symptoms. The incidence of extrapyramidal symptoms during aripiprazole therapy was similar to that with risperidone and placebo but lower than with haloperidol. Compared with placebo, the proportion of patients with increased plasma prolactin levels and QTc prolongation was similar in patients treated with aripiprazole 15 to 30 mg/day but was significantly increased with haloperidol and risperidone.