Olanzapine and diabetes

• prevalence of diabetes mellitus among individuals with schizophrenia is around twice that in the general population

• traditional or atypical antipsychotics may further increase the risk of developing diabetes
  • these are major concerns for patients who, because of schizophrenia, may have difficulty in self-managing diabetes, and who often have other cardiovascular risk factors (e.g. smoking, being overweight, low physical activity)
  • there is evidence that atypical antipsychotic drugs are more likely than traditional drugs to impair glucose intolerance
    • it is not known whether or not this is solely due to weight gain
      • a consensus conference in the USA concluded that the risk for the development of type 2 diabetes was highest with clozapine and olanzapine (2)
        • atypical antipsychotic drugs, particularly clozapine and olanzapine, can cause much worse metabolic side-effects including body weight gain, obesity, hyperlipidaemia, insulin resistance, hyperglycaemia and diabetes (3)
        • there are limited reports linking atypical antipsychotics with diabetic ketoacidosis (DKA) in patients with type 2 diabetes mellitus and with very severe hypertriglyceridaemia (serum triglycerides >22 mmol/L) (4)

Prior to initiation of atypical antipsychotic agents such as clozapine and olanzapine patients should have their baseline weight and BMI recorded with compulsory screening for the presence of diabetes mellitus and lipid abnormalities

• the American Diabetes Association/American Psychiatric Association published statements (5) recommended weight monitoring at 4, 8 and 12 weeks after initiating of therapy with new antipsychotic agents followed by quarterly routine visits to measure plasma glucose and lipids
• this should be followed by annual monitoring of fasting plasma glucose or HbA1c with lipid monitoring to occur at least every 5 years (5)

Reference:

1. Drug and Therapeutics Bulletin (2004); 42(8):57-60.
2. American Diabetes Association et al. Consensus development conference on antipsychotic drugs and obesity and diabetes. Diabetes Care 2004; 27: 596-601.
3. Stubbs B et al. The prevalence and predictors of type two diabetes mellitus in people with schizophrenia: a systematic review and comparative meta-analysis. Acta Psychiatr Scand. 2015 Aug; 132(2):144-57.
4. Berglund L et al. Evaluation and treatment of hypertriglyceridemia: an Endocrine Society clinical practice guideline.J Clin Endocrinol Metab. 2012 Sep; 97(9):2969-89.
5. American Diabetes Association, American Psychiatric Association, American Association of Clinical Endocrinologists, North American Association for the Study of Obesity. Consensus development conference on antipsychotic drugs and obesity and diabetes. Diabetes Care 2004;27:596-601