From the Guidelines
Taking a double dose of Quetiapine (Seroquel) can lead to severe side effects, including extreme drowsiness, confusion, rapid heartbeat, and low blood pressure, and should be avoided at all costs. According to the most recent guidelines, Quetiapine is a second-generation antipsychotic with a suggested starting dose of 25 mg (immediate release) p.o. stat, and it is recommended to reduce the dose in older patients and patients with hepatic impairment 1.
Potential Risks and Side Effects
- Extreme drowsiness
- Confusion
- Rapid heartbeat
- Low blood pressure
- Loss of consciousness or even life-threatening complications in severe cases
If you accidentally take a double dose, you should contact your healthcare provider or poison control center immediately. It is essential to follow your doctor's prescribed dosing schedule and never intentionally double your dose to make up for a missed dose. Quetiapine affects brain chemicals, and taking more than prescribed can disrupt these chemical balances significantly, leading to severe consequences.
Important Considerations
- Always follow your doctor's prescribed dosing schedule
- Keep all medications out of reach of children
- Contact your healthcare provider or poison control center immediately if you accidentally take a double dose
- Never intentionally double your dose to make up for a missed dose
- Reduce dose in older patients and patients with hepatic impairment, as recommended by the guidelines 1
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. 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.
If a double dose of Quetiapine (Seroquel) is taken, it may lead to an exaggeration of the drug's known pharmacological effects, including:
- Drowsiness and sedation
- Tachycardia
- Hypotension It is essential to seek medical attention immediately if an overdose is suspected. Treatment should focus on supportive measures, such as establishing and maintaining an airway, ensuring adequate oxygenation and ventilation, and administering activated charcoal and a laxative 2.
From the Research
Overview of Quetiapine Overdose
- Quetiapine is an atypical antipsychotic that has been used to treat schizophrenia, bipolar disorder, delirium, and agitation 3.
- Taking a double dose of quetiapine can lead to significant adverse effects, even in patients who have been taking the medication for a while 3, 4, 5.
Adverse Effects of Quetiapine Overdose
- Acute respiratory failure and severe central nervous system depression have been reported in patients who took a single dose of quetiapine, especially in elderly patients with underlying pulmonary pathology 3.
- Massive overdose of quetiapine can lead to coma, myoclonic jerks, generalized seizures, and transient mild hypotension 4.
- Quetiapine overdose can also cause QT interval prolongation, which can increase the risk of torsade de pointes and sudden cardiac death 6.
Management of Quetiapine Overdose
- Patients who overdose on quetiapine may require mechanical ventilation, supportive care in the intensive care unit, and close monitoring of their vital signs and cardiac function 3, 4, 7.
- The use of noradrenaline instead of adrenaline is recommended in the management of shock in patients with quetiapine overdose, as adrenaline can worsen hypotension 7.
Risk Factors for Adverse Effects
- Elderly patients, especially those with significant underlying pulmonary pathology, are at higher risk of adverse effects from quetiapine overdose 3.
- Female sex, coadministration of drugs associated with QTc interval prolongation, hypokalemia or hypomagnesemia, quetiapine overdose, cardiac problems, and coadministration of cytochrome P450 3A4 inhibitors are also risk factors for QTc interval prolongation and torsade de pointes 6.