What is the management for a quetiapine (Seroquel) overdose?

Management of Quetiapine (Seroquel) Overdose

The management of quetiapine overdose requires immediate supportive care with focus on airway protection, cardiovascular monitoring, and gastrointestinal decontamination as the primary interventions, as there is no specific antidote available.

Initial Assessment and Stabilization

1. Airway Management:

   • Establish and maintain a patent airway
   • Provide supplemental oxygen as needed
   • Intubate early if patient shows signs of decreased consciousness (GCS < 15) or respiratory depression 1
   • Ensure adequate oxygenation and ventilation

2. Cardiovascular Support:

   • Continuous cardiac monitoring is essential
   • Monitor for QT prolongation, tachycardia, and hypotension
   • Treat hypotension with IV fluids first
   • For refractory hypotension, use sympathomimetic agents (avoid epinephrine and dopamine due to potential worsening of hypotension from quetiapine's alpha-blocking effects) 1

3. Gastrointestinal Decontamination:

   • Gastric lavage if patient presents within 1 hour of ingestion and after airway is secured
   • Administer activated charcoal with a laxative (if patient is alert or airway is protected) 1
   • Caution: Risk of aspiration with induced emesis due to possible obtundation or dystonic reactions

Specific Monitoring and Management

Cardiovascular Monitoring

• Continuous ECG monitoring for arrhythmias and QT prolongation
• Avoid antiarrhythmic agents like disopyramide, procainamide, and quinidine which may worsen QT prolongation 1
• Monitor for tachycardia (common) and hypotension 2, 3

Neurological Assessment

• Monitor level of consciousness
• Treat seizures if they occur (reported in large overdoses) 2
• For severe extrapyramidal symptoms, administer anticholinergic medication 1

Laboratory Monitoring

• Electrolytes (particularly potassium)
• Blood glucose (hyperglycemia is common) 4
• Thyroid function tests (transient hypothyroidism reported) 4
• Drug levels if available (though not typically used to guide management)

Severity Assessment

Risk Stratification:

• Low risk: Reported dose <3g, GCS 15 at 4 hours post-ingestion, no co-ingestion of other toxic agents 2
• High risk: Reported dose >3g, decreased level of consciousness, cardiovascular instability

Disposition

• ICU Admission Criteria:

  • Ingestion >3g
  • Decreased level of consciousness (GCS <15)
  • Cardiovascular instability
  • Need for mechanical ventilation
  • Seizures or significant neurological symptoms

• Observation Period:

  • Minimum 24 hours for significant overdoses
  • Median length of stay in significant overdoses is approximately 35 hours 2
  • Patients may be discharged after normalization of vital signs and level of consciousness 5

Special Considerations

1. Multiple Drug Ingestion:

   • Consider co-ingestion of other substances, particularly opioids
   • If opioid overdose is suspected alongside quetiapine, administer naloxone first 5

2. Severe Overdose Management:

   • In cases of cardiovascular collapse unresponsive to conventional therapy, consider extracorporeal circulatory support in specialized centers 6

3. Common Pitfalls:

   • False positive immunoassay for tricyclic antidepressants may occur with quetiapine overdose 6
   • QTc prolongation may be overestimated due to tachycardia 2
   • Avoid epinephrine and dopamine for hypotension management due to potential worsening from quetiapine's alpha blockade 1

Remember that even extremely large overdoses (>30g) have been survived with appropriate supportive care 1, 7, but close monitoring and aggressive supportive management are essential for optimal outcomes.