Pediatric Ziprasidone Overdose

Abstract

We describe the first ziprasidone overdose with quantitative serum levels of a pediatric patient in coma and with pinpoint pupils. This case is an important contribution to the pediatric ziprasidone literature because it illustrates that ingestion of just 1 pill may result to profound mental status and respiratory depression in a child. H.C., a 30-month-old girl, presented to the emergency department approximately 30 minutes after an accidental ingestion of an adult family member's medication. The child was found on the floor surrounded by numerous pills and was witnessed to have ingested at least 1 tablet by a caregiver. After finding the child with the pills, the family observed the child for a brief period but transported her to the hospital after she became lethargic and unresponsive. The child received 2 doses of 0.4 mg of intravenous naloxone without change in her neurologic status. The child then underwent a rapid sequence intubation for airway protection and subsequently received gastrointestinal decontamination with 15 g of activated charcoal via the orogastric tube. Ziprasidone is an atypical antipsychotic drug that was approved by the Food and Drug Administration in February 2001 for the general treatment of schizophrenia in adults. Previously reported pediatric ziprasidone overdoses describe a syndrome of sedation, tachycardia, hypotonia, and coma consistent with that of the patient described in this paper. In pediatric ziprasidone overdose, QTc prolongation and hypotension have also been illustrated, but seizures have not been reported. An interesting aspect of this case is the development of pinpoint pupils unresponsive to naloxone. This phenomenon has been reported before with overdose of olanzapine, a similar atypical antipsychotic. The mechanism of miosis associated with overdose of atypical antipsychotics is unclear but is likely related to interference with central innervation of the pupil. Pupil size is maintained by a balance between sympathetic and parasympathetic neurohumeral tones. We propose that an overdose of an alpha-1 receptor blocking agent, such as ziprasidone, results in unopposed parasympathetic stimulation resulting in miosis.