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

Treatment for Seroquel (Quetiapine) Overdose

The management of quetiapine overdose requires immediate supportive care with airway protection, cardiovascular monitoring, and activated charcoal administration, as there is no specific antidote for quetiapine toxicity.

Initial Assessment and Stabilization

1. Airway Management:

   • Establish and maintain a patent airway
   • Intubate early if decreased level of consciousness (GCS < 8) or inability to protect airway 1, 2
   • Ensure adequate oxygenation and ventilation

2. Cardiovascular Monitoring:

   • Initiate continuous ECG monitoring immediately to detect arrhythmias
   • Monitor for QT prolongation, which is common in quetiapine overdose 1, 2
   • Check vital signs frequently with attention to hypotension and tachycardia

3. Gastrointestinal Decontamination:

   • Administer activated charcoal (if within 1-2 hours of ingestion and patient is alert or airway is protected) 1
   • Consider gastric lavage only after intubation if patient is unconscious and presenting within 1 hour of large ingestion 1
   • Administer a laxative with activated charcoal to prevent constipation

Management of Specific Complications

Cardiovascular Effects

• Hypotension:

  • Administer IV fluids (crystalloids)
  • Avoid epinephrine and dopamine as beta stimulation may worsen hypotension due to quetiapine's alpha-blocking properties 1
  • Consider norepinephrine or pure alpha-agonists if fluid resuscitation fails

• QT Prolongation/Arrhythmias:

  • Avoid Class IA and III antiarrhythmics (disopyramide, procainamide, quinidine) which may worsen QT prolongation 1
  • Correct electrolyte abnormalities, particularly hypokalemia

Neurological Effects

• CNS Depression:

  • Supportive care until drug effects resolve
  • Monitor level of consciousness
  • Protect airway if significantly sedated

• Extrapyramidal Symptoms:

  • Administer anticholinergic medications for severe extrapyramidal symptoms 1
  • Benztropine 1-2 mg IV or diphenhydramine 25-50 mg IV

Monitoring and Disposition

1. Laboratory Testing:

   • Electrolytes (particularly potassium)
   • Blood glucose (hyperglycemia is common) 3
   • Thyroid function tests (transient hypothyroidism may occur) 3
   • Cardiac enzymes if indicated

2. Duration of Monitoring:

   • All patients with significant quetiapine overdose should be admitted to an intensive care unit 2, 4
   • Continue monitoring until clinical effects resolve (typically 16-40 hours) 4
   • Tachycardia may persist for up to 40 hours 4

Special Considerations

• Multiple Drug Ingestion:

  • Consider co-ingestion of other substances, particularly opioids
  • If opioid co-ingestion is suspected, administer naloxone 5
  • For benzodiazepine co-ingestion, flumazenil is generally not recommended due to risk of seizures 5

• Experimental Therapies:

  • Intravenous lipid emulsion (ILE) therapy has been reported in case studies to improve level of consciousness in severe overdose 6, though this is not yet standard practice

Pitfalls and Caveats

• Do not induce emesis due to risk of rapid deterioration in mental status and aspiration 1
• Avoid flumazenil in undifferentiated overdose as it may precipitate seizures, especially with co-ingestion of tricyclic antidepressants 5
• Do not discharge patients prematurely as symptoms may persist or recur for up to 40 hours 4
• Do not use beta-agonists for hypotension as they may worsen hypotension in the setting of quetiapine-induced alpha blockade 1

Quetiapine overdose can cause rapid deterioration in level of consciousness and hemodynamic instability. Early airway protection, cardiovascular monitoring, and supportive care in an ICU setting are the cornerstones of management.