A case of hypoglycemia attributable to atypical antipsychotic drugs

We report a 55-year-old Japanese man who presented with symptomatic hypoglycemia attributable to atypical antipsychotic drugs (APD). He had been taking olanzapine, quetiapine, and paliperidone. One morning, his consciousness level dropped without inducement and his blood glucose was low. His symptoms improved after intravenous glucose infusion. These episodes reoccurred a few times, but ceased after APD were stopped. Physical examination did not find any organic disease that might cause hypoglycemia. Hyperglycemia, dyslipidemia, and body weight gain are well-documented side-effects of APD, but hypoglycemia is rare. There are a variety of hypotheses on how APD cause hypoglycemia: (1) Weight gain and dyslipidemia caused by APD might increase insulin resistance, meaning that excess insulin is secreted, causing hypoglycemia. (2) The quantity of basal insulin secreted by pancreatic beta cells might be enhanced by APD, which might cause hypoglycemia. (3) APD might work as an antagonist of muscarinic receptors such that insulin secretion might continue even after the glucose level has returned to normal, which might cause hypoglycemia. However, the mechanism is not fully understood and more research is needed.