Amoxapine overdose in a young man: a transient mitochondrial abnormality?

Amoxapine is a second-generation tricyclic antidepressant structurally related to the neuroleptic loxapine. It was previously marketed as an alternative to traditional tricyclic antidepressants because of alleged shorter onset of action and fewer cardiotoxic effects. However, various adverse reactions, including cardiac dysrhythmias, renal failure, coma, seizures, and neuroleptic malignant syndrome, were reported during therapy or after acute overdose. A 14-year-old boy ingested 1900 mg of amoxapine and developed seizures, hypertension, hyperpyrexia, altered mental status, myoglobinuria, renal failure, and transient magnetic resonance imaging (MRI) changes suggestive of hypertensive encephalopathy and neuroleptic malignant syndrome. Since mitochondrial disorders can cause multisystem failure, including encephalopathy, renal tubular dysfunction, and myopathy, a transient, toxic disorder of mitochondrial function was considered as the basis for the patient's clinical and MRI changes.