Management of diabetes mellitus occurring during treatment with olanzapine: report of six cases and clinical implications

In spite of conflicting reports, there is emerging evidence that at least two of the atypical antipsychotics, clozapine and olanzapine, are associated with an increased risk of developing glucose dysregulation or new onset diabetes mellitus. We report on the management of six patients who developed diabetes mellitus following treatment with otanzapine, five of whom had independent risk factors for diabetes. Olanzapine was changed to quetiapine in all patients with improvement in glycaemic control in two patients. In view of the uncertainty of the size and mechanism of the Link between olanzapine and diabetes, we discuss issues surrounding routine clinical management and monitoring of patients on antipsychotics and the clinical implications.