A Randomized, Double-blind, Comparison of the Efficacy and Safety of Amisulpride Versus Low-dose Amisulpride Plus Low-dose Sulpiride in the Treatment of Schizophrenia

Background: Antipsychotic monotherapy is recognized as the treatment of choice for patients with schizophrenia. Surveys have shown that antipsychotic drug combinations are frequently prescribed, yet few clinical studies have examined this practice. Amisulpride, an atypical antipsychotic agent, has low incidence of extrapyramidal symptom (EPS) but with high cost compared to sulpiride. It has been reported that mean doses of low-potency typical antipsychotics less than 600 mg/day of chlorpromazine equivalent dose has no higher risk of EPS than atypical antipsychotics. The objective of the study is to compare the efficacy and safety of the 800-mg/d amisulpride and 400-mg/d amisulpride plus 800-mg sulpiride in the treatment of acute psychotic exacerbations of schizophrenia.

Method: In this 6-week, double-blind, fixed-dose study, patients with schizophrenia (DSM-IV diagnosis) are randomly assigned to amisulpride (800 mg/d) or amisulpride (400 mg/d) plus sulpiride (800 mg/d). The hypothesis is that the two treatment groups have the similar efficacy and safety, but different cost. The efficacy assessment was the change from baseline in the score on the Clinical Global Impression-Severity (CGI-S), Positive and Negative Syndrome Scale (PANSS) and subscales (positive scale, negative scale, general psychopathology scale), Calgary Depression Scale for Schizophrenia (CDSS), and Global Assessment of Functioning (GAF). Safety assessments include the change from baseline on Simpson-Angus Rating Scale (SAS), Abnormal Involuntary Movement Scale (AIMS), Barnes Akathisia Scale (BAS), and UKU Side-effects Rating Scale (UKU), and the change from baseline in prolactin levels, body weight, vital sign, blood pressure, AC glucose level, and lipid profiles(cholesterol, high density lipid protein [HDL], low density lipid protein [LDL], and triglyceride [TG]).