Clozapine-induced Insulin-resistant Hyperglycemia in a Diabetic Patient

Clozapine is superior to all other antipsychotics in treatment-resistant schizophrenia. However, metabolic side effects are common while treating patients with clozapine. Administering clozapine in a patient who already is diabetic involves careful weighing of risks and benefits. Here, we report our experience of starting clozapine in a known diabetic patient. Clozapine was started in a patient with treatment-resistant psychosis in view of suicidal risk. Her diabetes mellitus was under good control with oral medications. After initiation of clozapine, blood sugars increased several fold within few days. Blood glucose continued to increase even with high doses of insulin and insulin infusion. Finally, blood sugars came under control only after discontinuation of clozapine. Precautionary measures while initiating clozapine in a diabetic patient are suggested - close monitoring of blood sugar during the initial few days and intensive intervention if blood sugar levels increase. Discontinuation of clozapine should also be kept in mind as a last resort.