Amisulpride: a review of its use in the management of schizophrenia

Abstract

Amisulpride (Solian), a substituted benzamide derivative, is a second-generation antipsychotic that preferentially binds to dopamine D2/D3 receptors in limbic rather than striatal structures. High dosages preferentially antagonise postsynaptic D2/D3 receptors, resulting in reduced dopamine transmission, and low dosages preferentially block presynaptic D2/D3 receptors, resulting in enhanced dopamine transmission. Amisulpride (200-1200 mg/day) was at least as effective as haloperidol and as effective as risperidone or olanzapine, in studies of up to 1 year in patients with schizophrenia manifesting predominantly positive symptoms. Amisulpride (50-300 mg/day) was significantly more effective than placebo in studies of up to 6 months in patients manifesting predominantly negative symptoms. Quality of life was also improved significantly more in patients receiving amisulpride than in those receiving haloperidol in 4- and 12-month studies in patients with predominantly mixed symptoms. Amisulpride was generally well tolerated in clinical trials. In patients with predominantly positive symptoms, amisulpride appeared to be better tolerated than haloperidol and was tolerated as well as risperidone and olanzapine. The incidence of extrapyramidal adverse effects with amisulpride was lower than with haloperidol but was generally similar to risperidone or olanzapine. Weight gain with amisulpride was less than that with risperidone or olanzapine and, unlike these agents, amisulpride does not seem to be associated with diabetogenic effects. Plasma prolactin levels are increased during amisulpride therapy and amenorrhoea occurs in about 4% of women. The incidence of adverse events with low dosages of amisulpride (< or = 300 mg/day) in patients with predominantly negative symptoms was similar to that observed with placebo. In conclusion, oral amisulpride (200-1200 mg/day) is at least as effective as haloperidol, and as effective as risperidone or olanzapine, in the treatment of patients with schizophrenia manifesting predominantly positive symptoms. In the treatment of patients manifesting predominantly negative symptoms, low dosages of amisulpride (50-300 mg/day) are significantly more effective than placebo. Amisulpride appears to be better tolerated than haloperidol, causing a lower incidence of extrapyramidal adverse effects and an improved quality of life. Compared with risperidone or olanzapine, amisulpride is more likely to cause hyperprolactinaemia, but has a lower propensity to cause weight gain and does not seem to be associated with diabetogenic effects. Thus, amisulpride is an effective and well tolerated option for the first-line treatment of patients with acute schizophrenia as well as for those requiring long-term maintenance therapy.