LOSS OF CONSCIOUSNESS FROM ACUTE QUETIAPINE OVERDOSAGE

Background: Quetiapine (Seroquel (R)) is a new atypical antipsychotic agent developed for the treatment of schizophrenia. This dibenzothiaze pine derivative possesses high affinity for 5-HT2 receptors with lower affinity for D-1 and D-2 dopamine receptors. In comparison to other a ntipsychotic agents, quetiapine has less antimuscarinic and alpha(1) a ntagonist receptor activity. Overdose reports outside of clinical tria ls are limited. We report an intentional overdose of quetiapine by a s chizophrenic. Case Report: A 26-year-old female presented to the emerg ency department following an alleged ingestion of greater than 10,000 mg of quetiapine. At 1 1/2 hours postingestion, the patient was awake, ambulatory, and responded to verbal stimuli. At 2 1/2 hours postinges tion, the patient experienced a decreased level of consciousness and r esponded only to deep pain. Physical findings included sinus tachycard ia, pupils 3-4 mm and sluggish, and BP 135/70. Within 16 hours, the pa tient became awake and alert and was subsequently extubated. Serum ele ctrolytes and blood count were unremarkable. The electrocardiogram at 18 hours postingestion showed a sinus tachycardia, which lasted for ap proximately 40 hours postingestion. A follow-up electrocardiogram at 4 2 hours postingestion was normal. Conclusion: This ingestion resulted in the loss of consciousness with need for airway protection and persi stent tachycardia. Major overdoses of quetiapine warrant close observa tion in an intensive care setting.