Severe recurrent hypoglycaemia following discontinuation of olanzapine

Severe hypoglycaemia is a diagnostic challenge.1 It is often explained by mismatch between insulin doses, food ingestion and exercise. Recurrent hypoglycaemia can indicate underlying medical problems. Drug related events usually concern insulin or sulphonylureas. However, withdrawal of drugs which can cause insulin resistance can be causative if insulin or sulphonylureas continue.2We report the case of an insulin-treated patient who presented with severe recurrent hypoglycaemia. After exclusion of secondary causes of hypoglycaemia it was established that at the time of diagnosis of diabetes he had been taking olanzapine. This had subsequently been discontinued. Olanzapine is recognised to cause diabetes and diabetic ketoacidosis. Our patient was able to discontinue insulin therapy.