Rosiglitazone in the Assistance of Metabolic Control during Olanzapine Administration in Schizophrenia: A Pilot Double-blind, Placebo-controlled, 12-week Trial

Introduction: Excessive body weight gain (BWG), hyperglycemia and dyslipidemia are important side effects of olanzapine. We assessed the effects of rosiglitazone on BWG, the insulin resistance index (HOMA-IR), lipids, glycated hemoglobin and fibrinogen in olanzapine-treated schizophrenia patients. Methods: Thirty patients taking olanzapine (10-20mg daily for 8 months) were randomly allocated to rosiglitazone (n=15: 4 to 8 mg daily) or placebo (n=15) in a 12-week double-blind protocol. Anthropometric and biochemical variables were evaluated at baseline, weeks 6 and 12. Results: The rosiglitazone and placebo groups gained 3.2 +/- 4.5 and 2.2 +/- 2.3kg, respectively (p=0.65). Insulin and the HOMA-IR significantly decreased after rosiglitazone (p<0.05). Rosiglitazone did not improve the lipid profile, fibrinogen and Hb1c levels. Discussion: The positive impact of rosiglitazone was limited to improved glycemic control. It cannot be recommended for metabolic control during olanzapine treatment.