Due to the limitations of certain antipsychotic treatments with respect to efficacy and safety, clinicians may sometimes wish to switch a patient to another antipsychotic. The comparative risks associated with different methods of antipsychotic drug discontinuation are relatively unknown. The present study compared 3 strategies to determine an optimal method for switching from amisulpride to ziprasidone in patients suffering from schizophrenia or schizoaffective disorder.

This was a 3-month randomized, multicenter, open-label study in three-parallel groups. 102 chronic outpatients with schizophrenia or schizoaffective disorder were randomized at D1 to one of three switching strategies. Strategy I: abrupt discontinuation of amisulpiride before initiation of ziprasidone; strategy II: reduction to 50% of previous dose of amisulpiride from D1 to D7 then discontinuation; strategy III: reduction to 50% of previous dose of amisulpiride from D3 to D7 then discontinuation. At D1 all patients received the same dose of ziprasidone. Main efficacy assessments included the Negative and Positive Syndrome Scale (PANSS), Brief Psychiatric Rating Scale (BPRS) and Clinical Global Impression of Severity and Improvement (CGI-S and CGI-I). Main safety assessments included the Extrapyramidal Symptom Rating Scale (ESRS), and Barnes Akathisia Scale (BAS).

Clinical improvement was comparable whatever the switching strategy used. Safety and tolerability of ziprasidone in switching were confirmed. The strategy III was associated with an increased incidence of adverse events leading to patient withdrawal during the switch.

similar efficacy results were obtained with the three switching strategies. However, one of them was less well tolerated.