pms-Quetiapine Overdosage

Experience: Clinical Trials: One death has been reported in a clinical trial following an overdose of 13,600 mg of quetiapine alone, however, survival has also been reported in acute overdoses of up to 30,000 mg of quetiapine. Most patients who overdosed reported no adverse events or recovered fully from the reported events.
Post-Marketing: In post-marketing experience, there have been cases of coma and death in patients taking a quetiapine fumarate overdose. The lowest reported dose associated with coma has been in a patient who took 5,000 mg and had a full recovery within 3 days. The lowest reported dose associated with a death was in a patient who took 6,000 mg.
In post-marketing experience, there were cases reported of QT prolongation with overdose.
Patients with pre-existing severe cardiovascular disease may be at an increased risk of the effects of overdose (see Cardiovascular: Hypotension and Syncope under Precautions).
Symptoms: In general, reported signs and symptoms were those resulting from an exaggeration of the drug's known pharmacological effects (e.g., drowsiness and sedation, tachycardia, hypotension and anticholinergic effects).
Treatment: There is no specific antidote to quetiapine. In cases of severe intoxication, the possibility of multiple drug involvement should be considered, and intensive care procedures are recommended, including establishing and maintaining a patent airway, ensuring adequate oxygenation and ventilation, and monitoring and support of the cardiovascular system. In this context, published reports in the setting of anticholinergic symptoms describe a reversal of severe central nervous system effects, including coma and delirium, with administration of IV physostigmine (1-2 mg), under continuous ECG monitoring. If physostigmine salicylate is used, atropine sulfate should be available to reverse excessive cholinergic effects such as bradycardia, marked salivation, emesis and bronchospasm.
In cases of quetiapine overdose refractory hypotension should be treated with appropriate measures such as IV fluids and/or sympathomimetic agents (epinephrine and dopamine should be avoided, since beta stimulation may worsen hypotension in the setting of quetiapine-induced alpha blockade).
Close medical supervision and monitoring should be continued until the patient recovers.