How do we choose between atypical antipsychotics? The advantages of amisulpride.

Clinician choice of an atypical antipsychotic may depend on a number of factors such as perceived efficacy, tolerability and cost. It is also important that the choice of treatment takes into consideration the previous response to treatment, experience of side-effects and personal clinical characteristics. The receptor-affinity profiles of the atypical antipsychotics differ; with the exception of amisulpride, a selective D2/D3 antagonist, all the atypical antipsychotics exhibit a greater affinity for the serotonin-2A receptors than dopamine receptors. However, there is no evidence that the variation in receptor affinities is relevant to efficacy. Indeed, the crucial factor may be fast dissociation from low affinity for the D2 receptor. Tolerability also varies between the atypical antipsychotics and the side-effect profile may be related to the receptor-affinity profile of the individual drugs. Extrapyramidal side-effects are generally less of a problem with most atypical drugs than with conventional drugs, but weight gain, loss of glycaemic control, sedation and hyperprolactinaemia remain problematic in some patients. Amisulpride is effective for the treatment of both positive and negative symptoms, and is well tolerated with regard to weight gain, glucose tolerance and sedation. In two clinical trials, the AMIRIS and SOLIANOL studies, amisulpride demonstrated clear advantages over some other atypical antipsychotics with respect to negative symptoms, depressive symptoms and weight gain.