The lack of effect of ziprasidone on platelet serotonin concentration in schizophrenic patients

Abstract

Rationale Ziprasidone is an atypical antipsychotic, with the unique multireceptor-binding profile. If affects multiple serotonergic (5-HT) receptors, inhibits 5-HT transporter (5-HTT) and inhibits synaptic 5-HT reuptake. These effects might be responsible for the antidepressant effect of ziprasidone. Objectives Since there is a lack of in vivo data on the effects of ziprasidone on 5-HT concentration in humans, the aim of the study was to investigate the effect of ziprasidone treatment on platelet 5-HT concentration in patients with schizophrenia or schizoaffective disorders. Methods In and open-label study, the effect of ziprasidone (average dose of 109 mg/day) on platelet 5-HT concentration (determined fluorimetrically) was evaluated at baseline and after 7 and 28 days of treatment in 21 male and female patients with schizophrenia or schizoaffective disorders. Results Ziprasidone treatment for 7 or 28 days did not significantly change baseline platelet 5-HT concentration in male and female schizophrenic patients. Platelet 5-HT concentration was not correlated with gender, age and smoking status of patients. Conclusions There was a lack of effect of ziprasidone treatment on platelet 5-HT concentration in male and female schizophrenic patients. Although the clinical effects of ziprasidone were evident after 28 days of treatment, and ziprasidone has the highest potency among atypical antipsychotics to block 5-HTT, our data did not confirm the hypothesis that ziprasidone treatment decreases platelet 5-HT concentration, at least not in the doses used in our study.