>[!key points] >**risk dose:** >3g (>100mg kids) # effects - onset within 2-4 hours and may last 24-72 hours - dose-dependent CNS depression ranging from sedation to coma and brisk tachycardia - Dose <3g: mild-to-moderte sedation and sinus tachycardia >120 BPM - Dose >3g: increasing risk of CNS depression, coma, hypotension. delirium (from [[Anticholinergic toxicity|anticholinergic]] effects) and [[Seizures]] may occur (<5% of cases) - co-ingestion of ethanol or other sedative-hypnotic agents increases risk of coma and loss of airway protection - *rare* to have clinically significant QT prolongation; no reports of TdP # mechanism - antagonist of D2, serotonin, histamine, muscarinic, peripheral alpha - high protein bind, large Vd - mostly metabolised by P450 # management - supportive - normal to have HR >120, no specific management required - **noradrenaline** preferred to adrenaline (adrenaline beta2 activation may paradoxically exacerbate hypotension of quetiapine toxicity) # disposition - children observe 4 hours if >100 mg (8h if modified release) → extramyramidal movements might occur up to 3 days after ingestion - patients with <3g and are clinically well, not sedated, normal ECG at 4 hours (8 if MR) can be discharged - pts with >3g or clinical features of intoxication should be admitted