▴ Aripiprazole, an oral quinolinone (carbostyril), is a novel atypical antipsychotic that has partial agonist activity at dopamine D2and serotonin 5-HT1Areceptors, and antagonist activity at 5-HT2Areceptors.▴ Aripiprazole had a rapid onset of action (as early as day 4) and was effective in the treatment of patients with bipolar I disorder experiencing an acute manic or mixed episode. Aripiprazole was generally significantly more effective than placebo in improving manic symptoms (as defined by a mean change in Young Mania Rating Scale Total Score) in 3-week placebo-controlled trials, and demonstrated superior effectiveness to haloperidol (response rate 50% vs 28.4% in patients remaining on treatment) in a 12-week comparative trial.▴ The time to relapse of symptoms in stabilised patients with bipolar I disorder who previously experienced a manic episode was significantly longer with aripiprazole than with placebo in a 26-week relapse prevention study.▴ Aripiprazole was generally well tolerated and was not associated with weight gain, serum prolactin elevation or clinically significant QTc interval prolongation.▴ Changes from baseline in extrapyramidal symptom scale scores with aripiprazole were small (<0.5 units), but generally significantly greater than with placebo in one of the 3-week trials. In the 12-week trial, changes from baseline were significantly smaller with aripiprazole than with haloperidol.Table. Features and properties of aripiprazole (Abilify™)