Rhabdomyolysis in Clozapine Overdose

Clozapine is used for decennia for the treatment of schizophrenia. Agranulocytosis, diabetic ketoacidosis, gastrointestinal hypomotility, and myocarditis are well-known adverse effects of clozapine, which are sometimes life threatening. Here we report a case of rhabdomyolysis upon an acute overdose of clozapine.

A male patient, 36 years, with elevated creatinine kinase levels (9899 U/l), developed rhabdomyolysis afterafter admission to the emergency department. Approximately 2-4 h earlier he had intoxicated himself with his maintenance oral medication clozapine 125 mg, temazepam 20 mg and lorazepam 1.5 mg. Co-medications, and physical and laboratory examinations did not reveal other risk factors for rhabdomyolysis. According to the Naranjo probability scale there was a probable relation between clozapine dose and symptoms, that developed approximately 2-4 h after the auto-intoxication of 125 mg tablets. At day 5 of hospitalization, clozapine and creatinine kinase levels returned to normal and the patient was discharged with no somatic sequelae.

Elevated creatinine kinase levels in acute clozapine intoxication may be an indicator that rhabdomyolysis may be involved.