From the FDA Drug Label
In clinical trials, survival has been reported in acute overdoses of up to 30 grams of quetiapine. Most patients who overdosed experienced no adverse reactions or recovered fully from the reported reactions. Death has been reported in a clinical trial following an overdose of 13. 6 grams of quetiapine alone. In general, reported signs and symptoms were those resulting from an exaggeration of the drug's known pharmacological effects, i.e., drowsiness and sedation, tachycardia and hypotension. Patients with pre-existing severe cardiovascular disease may be at an increased risk of the effects of overdose [see Warnings and Precautions (5. 11)]. One case, involving an estimated overdose of 9600 mg, was associated with hypokalemia and first degree heart block. In post-marketing experience, there were cases reported of QT prolongation with overdose. There were also very rare reports of overdose of quetiapine alone resulting in death or coma.
The effects of a Quetiapine (Seroquel) overdose may include:
- Drowsiness and sedation
- Tachycardia and hypotension
- Hypokalemia and first degree heart block in some cases
- QT prolongation in post-marketing experience
- Death or coma in very rare cases, including a reported death following an overdose of 13.6 grams of quetiapine alone 1 Patients with pre-existing severe cardiovascular disease may be at an increased risk of the effects of overdose.
From the Research
Seroquel (quetiapine) intoxication requires immediate medical attention, and treatment should prioritize stabilization of vital signs and management of potential complications, as evidenced by a case report where intravenous lipid emulsion was successfully used to treat cardiovascular collapse after a severe quetiapine overdose 2. The effects of a quetiapine overdose can be severe and potentially life-threatening, with symptoms including extreme drowsiness, rapid heartbeat, low blood pressure, confusion, seizures, and potentially coma.
- The severity of the overdose depends on the amount ingested, whether other substances were involved, and the person's overall health status.
- Treatment typically occurs in a hospital setting and may include activated charcoal, cardiac monitoring, IV fluids, and supportive care.
- In cases of severe quetiapine poisoning, intravenous lipid emulsion (ILE) may be considered as a treatment for severe cardiovascular instability resulting from quetiapine poisoning refractory to maximum conventional therapy, as shown in a case report where ILE was used to successfully resuscitate a patient with cardiovascular collapse after a severe quetiapine overdose 2.
- Vasopressor therapy, such as noradrenaline, may be necessary to manage hypotension caused by quetiapine overdose, as it has less affinity for α2- and β2-receptors, but maintains α1-receptor agonism, making it a preferred choice over adrenaline 3.
- Delirium due to quetiapine intoxication is a potential complication, and treatment is mainly supportive, with physostigmine described as a specific treatment for anticholinergic delirium/toxidrome 4.