Quetiapine poisoning: a case series

Area of Science:

• Toxicology
• Pharmacology
• Emergency Medicine

Background:

• Quetiapine is an atypical antipsychotic used to treat schizophrenia and bipolar disorder.
• Overdose cases require understanding of clinical effects and management strategies.

Purpose of the Study:

• To describe the clinical effects and outcomes of quetiapine overdose.
• To identify factors predicting the need for intensive care unit (ICU) admission and prolonged hospitalization.

Main Methods:

• Prospective data collection from a regional toxicology service database.
• Inclusion of 45 quetiapine poisoning cases, with detailed extraction of ingestion, clinical features, investigations (ECG), and outcomes.
• Correlation analysis between ingested dose, peak drug concentration, and clinical outcomes.

Main Results:

• 18 patients with quetiapine assay results were analyzed.
• Median length of stay was 35 hours, with 9 patients admitted to the ICU.
• Seizures, delirium, and need for mechanical ventilation were observed; no deaths or arrhythmias occurred.
• Ingested dose correlated with peak concentrations, ICU admission, and length of stay.
• A reported dose <3g and Glasgow Coma Scale score ≥15 predicted shorter stays and no ICU admission.

Conclusions:

• Quetiapine overdose primarily causes CNS depression and sinus tachycardia.
• Large overdoses may necessitate intubation and ventilation.
• Prolonged QTc interval's clinical significance is uncertain due to tachycardia overcorrection.
• A reported dose <3g in non-drowsy patients without co-ingestion predicts favorable outcomes.