Aripiprazole.

Aripiprazole is a new chemical entity with a unique pharmacological profile. It has strong affinities for certain dopamine receptors, and intermediate affinity for serotonin, adrenergic and histamine receptors. Partial agonism of the D2 dopamine and 5HT1A serotonin receptors, and antagonism of the 5HT2 serotonin receptor are believed to be the functional basis of its therapeutic efficacy. Its clinical effects are best documented in patients suffering from schizophrenia and bipolar disorder, in which it has been demonstrated to have antipsychotic and antimanic properties superior to placebo in dose ranges of 10-30 mg/day. Two published longer term trials document maintenance of antipsychotic effects and relapse prevention in schizophrenia patients. In general, aripiprazole seems to be a well-tolerated drug, especially with regard to metabolic side effects. The most commonly reported side effects include restlessness/akathisia, somnolence and nausea. These may be dose-dependent and usually occur early on during treatment, with many patients developing tolerance. Aripiprazole is an interesting and important addition to the currently available spectrum of antipsychotic drugs. Further studies in other indications and clinical trials that confirm results from the Phase II and III clinical development programme are eagerly awaited.