Quetiapine is a second generation atypical antipsychotic agent and is common in intentional overdoses. Symptoms of overdose are sedation, confusion, delirium, coma, tachycardia and hypotension. CNS depression is predictable and dose dependent. Seizures occur infrequently.
Hypotension is common. Most patients are otherwise healthy adults and will tolerate mild hypotension. Excessive IV fluid loading is not required as long as patients appear clinically well perfused. Clinically significant QT prolongation is rare and torsades de pointes has not been reported.
Risk assessment:
<3 g mild to moderate sedation and sinus tachycardia
>3 g Increasing risk of CNS depression progressing to seizures and coma.
Onset of symptoms may occur within 2-4 hours and may last 24-72 hours. Sedation is common and therefore decontamination is contraindicated. For the majority observation and supportive treatment is sufficient. Coma and profound hypotension will require Intensive Care treatment with invasive fluid management and vasopressor support.