Delayed-Onset olanzapine-induced rhabdomyolysis

Olanzapine is a commonly used and effective second-generation antipsychotic agent used for the control of paranoia and agitation in schizophrenia and bipolar disorder as well as in the behavioural and psychological symptoms of dementia. Serious side effects of treatment are uncommon but spontaneous rhabdomyolysis represents a rare complication. We describe here a patient treated with a stable dose of olanzapine for more than 8 years who developed acute severe rhabdomyolysis without an identifiable trigger and without features suggestive of neuroleptic malignant syndrome. The rhabdomyolysis was atypical in its delayed onset and severity with a creatine kinase level of 345 125 U/L, the highest level reported in the available literature. We also describe the clinical manifestations of delayed-onset olanzapine-induced rhabdomyolysis and its differentiation from neuroleptic malignancy syndrome, and we highlight key aspects of management to prevent or minimise further complications such as acute kidney injury.