Comparison of the metabolic effects observed in patients treated with ziprasidone versus olanzapine

This study aimed to examine the impact of ziprasidone and olanzapine on QTc interval, weight and metabolic parameters in adults with schizophrenia and other psychoses. A retrospective cohort chart review was performed of 191 randomly selected patients who were being treated with ziprasidone or olanzapine in an integrated health care system. Significant differences on QTc interval were not observed. A significant weight gain was observed in olanzapine-treated patients (P<0.001) but not in the ziprasidone-treated cohort (P>0.05). Furthermore, adverse metabolic changes associated with olanzapine administration were significant with respect to effects on total cholesterol (P=0.01), triglycerides (P=0.05) and haemoglobin A1C (HbA1C) (P<0.05), whereas significant favourable metabolic effects were observed in ziprasidone-treated patients with regard to total cholesterol (P<0.05), low-density lipoprotein (LDL) (P<0.01), high-density lipoprotein (HDL) (P<0.05) and HbA1c (P<0.05). Our results suggest that these two atypical antipsychotics are safe and well tolerated from a cardiovascular standpoint, with no differences in QTc interval prolongation being observed. Olanzapine-treated patients exhibited significant weight increases, whereas ziprasidone-treated patients exhibited weight loss. Olanzapine treatment was also associated with significant adverse effect on patient's lipid profile and HbA1c. These adverse metabolic effects were not observed in ziprasidone-treated patients although favourable effects were observed with regard to effect on total cholesterol, LDL, HDL and HbA1c.