Survival from coma induced by an intentional 36-g overdose of extended-release quetiapine

Quetiapine is a second-generation antipsychotic drug approved for the treatment of bipolar disorders and schizophrenia. Acute quetiapine overdose is rare, and quetiapine has long been thought to be safer than other antipsychotics. Nevertheless, as reported in the literature, the severity of the effect of quetiapine overdose has not been associated with a high serum concentration of the drug or with the reported ingested dose. In this article, we report a case of survival from coma induced by a massive extended-release (XR) quetiapine ingestion at a dose greater than reported in some previous fatal cases. A 34-year-old woman with chronic schizophrenia ingested 36 g of quetiapine fumarate XR for attempted suicide. She was initially lethargic, but her clinical conditions rapidly deteriorated and she collapsed unconscious. The woman was taken to the nearest hospital, where the medical emergency team found her in deep coma with response only to deep painful stimuli (Glasgow Coma Scale 9). An endotracheal tube was inserted for airway protection, and the patient was transferred to a critical care area for ventilatory support and maintenance of hydration status and electrolytic balance. Spontaneous breathing was restored in approximately 36 hours, and a few days later, she was discharged without reporting clinical complications. This is the first case of coma induced by an intentional 36-g overdose of quetiapine XR. Given the widespread use of quetiapine and the lack of information about its toxicity in overdose, this case report reinforces the importance of closely monitoring patients taking quetiapine and helps to better define the safety of this drug.