Ziprasidone versus Olanzapine in the weight gain associated with the treatment of schizophrenia: A six-month double-blind randomized parallel group study

Background and Objectives: Previous data from safety analysis indicate that olanzapine can result in substantial weight gain, while no change has been observed with ziprasidone. Obesity may be a threat to health and cause subjects to discontinue their antipsychotic medication. To further evaluate the differential effects of ziprasidone and olanzapine on weight gain, a study was carried out having body weight as the primary efficacy endpoint. Methods: A six-month randomized, double-blind, parallel study was carried out in male and female subjects aged 18-70 years with a primary diagnosis of schizophrenia (DSM-IV-TR) and a clinical condition requiring treatment initiation with a new antipsychotic, ziprasidone or olanzapine 1:1, to assess treatment-related weight changes. Fifty patients were included. Efficacy outcomes were assessed at baseline and at weeks 1, 4, 12, 18 and 24. The primary efficacy endpoint was the percent change from baseline in body weight at week 24. Safety was also assessed. Results: At week 24, there was a significantly greater increase in body weight (7.5%, p <0.0001) in patients treated with olanzapine than in those treated with ziprasidone and the number of subjects who had a weight gain > 7% was significantly higher in the olanzapine compared to the ziprasidone group (n = 11 [47.8%]) vs n = 3 [11.1%]; OR = 6.246, p-value = 0.0150). PANNS-N significantly decreased in both groups. Most AEs were moderate or mild in both groups. Conclusions: Olanzapine increases body weight significantly over ziprasidone at week 24. However, treatment with either ziprasidone or olanzapine improved PANSS positive, negative and general psychopathology scores and was well tolerated.