Atypical Antipsychotics and the Risk for New-Onset Diabetes

42 yo AAM with bipolar disorder was prescribed Zyprexa (olanzapine) and now his fasting blood glucose (FBG) is 200. He has no symptoms.

What is his risk for developing diabetes secondary to Zyprexa?
6-15% of patients with schizophrenia may have diabetes, and a similar percentage may have impaired glucose tolerance. This is well above the rate of DM in the general U.S. male population age 20–39 years (1.1%)
The atypical antipsychotics increase the risk for developing DM by 9% as compared with the typical antipsychotics.

What should we do now?
Discontinue Zyprexa. If the patient still needs an atypical antipsychotic, Risperdal has a lower risk for hyperglycemia.
His FBG should be monitored and if diagnosed with diabetes, he should be treated.

What are the chances for resolution of hyperglycemia if Zyprexa is stopped?
No randomized controlled trials have been done. The available evidence is anecdotal (case reports). In 14 patients with new-onset diabetes secondary to treatment with clozapine, olanzapine or quetiapine, only two patients had a subsequent resolution (antipsychotic therapy was ongoing).

Is the risk for diabetes the same with all atypical antipsychotics?
No. The risk is clear in patients treated with clozapine or olanzapine, less clear in patients taking risperidone and quetiapine (some studies show an increased risk for diabetes, while others do not). There is limited data about aripiprazole and ziprasidone.

References:
Prevalence of diabetes and impaired glucose tolerance in patients with schizophrenia - British Journal of Psychiatry 2004
Association of Diabetes Mellitus With Use of Atypical Neuroleptics in the Treatment of Schizophrenia - Am J Psychiatry 2002
New-onset diabetes and ketoacidosis with atypical antipsychotics - Schizophr Res 2003
Antipsychotics and diabetes: review of non-prospective data - British Journal of Psychiatry 2004
Consensus Development Conference on Antipsychotic Drugs and Obesity and Diabetes - Diabetes Care 2/04, American Diabetes Association
Second-generation versus first-generation antipsychotic drugs for schizophrenia: a meta-analysis. Stefan Leucht et al. The Lancet, Volume 373, Issue 9657, Pages 31 - 41, 3 January 2009.

Updated: 01/03/2009