Objective: The association of hyperglycemia and hypercholesterolemia with use of atypical antipsychotics has been documented in case reports and uncontrolled studies. The authors' goal was to assess the effects of clozapine, olanzapine, risperidone, and haloperidol on glucose and cholesterol levels in hospitalized patients with schizophrenia or schizoaffective disorder during a randomized double-blind 14-week trial.
Method: One hundred fifty-seven patients with schizophrenia or schizoaffective disorder who were inpatients at four hospitals were originally included in the study. The 14-week trial consisted of an 8-week fixed-dose period and a 6-week variable-dose period. Planned assessments included fasting glucose and cholesterol, which were collected at baseline and at the end of the 8-week period and the following 6-week period.
Results: One hundred eight of the 157 patients provided blood samples at baseline and at least at one point after random assignment to clozapine, olanzapine, risperidone, or haloperidol during the treatment trial. Seven of these patients had diabetes; their glucose levels were >125 mg/dl at baseline. Data from 101 patients were used for statistical analyses. During the initial 8-week period there was an overall significant increase in mean glucose levels. There were significant increases in glucose levels at the end of the 8-week fixed-dose period for patients given clozapine (N=27) and those given haloperidol (N=25). The olanzapine group showed a significant increase of glucose levels at the end of the 6-week variable-dose period (N=22). Fourteen of the 101 patients developed abnormal glucose levels (>125 mg/dl) during the trial (six with clozapine, four with olanzapine, three with risperidone, and one with haloperidol). Cholesterol levels were increased at the end of the 8-week fixed-dose period for the patients given clozapine (N=27) and those given olanzapine (N=26); cholesterol levels were also increased at the end of the 6-week variable-dose period for patients given olanzapine (N=22).
Conclusions: In this prospective randomized trial, clozapine, olanzapine, and haloperidol were associated with an increase of plasma glucose level, and clozapine and olanzapine were associated with an increase in cholesterol levels. The mean changes in glucose and cholesterol levels remained within clinically normal ranges, but approximately 14% of the patients developed abnormally high glucose levels during the course of their participation in the study.