AMISULPRIDE - A REVIEW OF ITS PHARMACODYNAMIC AND PHARMACOKINETIC PROPERTIES AND THERAPEUTIC EFFICACY IN THE MANAGEMENT OF SCHIZOPHRENIA

Amisulpride is a substituted benzamide. It is a dopamine antagonist wi th high selectivity for dopamine D-2 and D-3 receptors. In high doses, amisulpride exhibits dopaminergic blocking activity similar to that i nduced by classical antipsychotic agents, whereas in low doses it appe ars to facilitate dopaminergic transmission. In well controlled studie s of patients with primary negative symptoms of schizophrenic who had high negative and low positive symptoms scores, amisulphide 50 to 300 mg/day was more (2 to 12 mg/day) in less rigorous trials which include d patients with negative symptoms of schizophrenia. At higher dosages (600 to 1200 mg/day), amisulpride exhibits efficacy similar to that of haloperidol 5 to 40 mg/day or flupenthixol 25 mg/day in patients with positive symptoms of schizophrenia. In low and high dosages, amisulpr ide is generally well tolerated. Extra-pyramidal symptoms (EPS) induce d by amisulpride can occur at both low and high dosages and are dose-d ependent. Symptoms are generally mild or moderate. In comparative tria ls, amisulpride caused an incidence of EPS similar to that with placeb o and lower than that caused by haloperidol, flupenthixol or fluphenaz ine. Neuroendocrine adverse events were reported rarely with low-dose amisulpride and at similar incidences with amisulpride greater than or equal to 600 mg/day and haloperidol 16 mg/day. Insomnia and excitatio n occurred rarely. As classical antipsychotic drugs are not generally effective in reducing negative symptoms of schizophrenia, amisulpride should be considered a promising agent in the management of patients w ith schizophrenia who have predominantly negative symptoms. While amis ulpride does not offer superior efficacy over classical antipsychotic in the management of patients with positive symptoms of schizophrenia, its lower potential for causing EPS justifies consideration of its us e, especially in patients intolerant of classical antipsychotics.