II. Pharmacokinetics
- See Quetiapine (for Pharmacokinetics and mechanisms)
III. Signs
-
Tachycardia
- Related to Quetiapine as a weak Muscarinic Antagonist (M1)
-
Hypotension
- Related to Quetiapine as a potent alpha-1 Adrenergic ReceptorAntagonist
- Somnolent with Miosis
- Mimics Opioid Overdose
- Sedation related to weak Antagonist activity at Dopamine (D2), muscarinic (M1) and Serotonin (5HT-1A)
IV. Labs
- See Unknown Ingestion
- Urine drugs screen may show false positive Tricyclic Antidepressant in Quetiapine Overdose
V. Diagnostics: Electrocardiogram
- Tachycardia
-
QTc Prolongation
- Quetiapine in Overdose may impact delayed rectifier current
-
QRS Widening
- Quetiapine in Overdose may block fast Sodium channels
VI. Management
- See Unknown Ingestion (consider coingestions)
-
Decontamination
- Consider Activated Charcoal in alert patient if presentation <1-2 hours (especially extended release form)
-
ABC Management
- Apnea is rare with Quetiapine Overdose, but Endotracheal Intubation as needed
-
Hypotension Management
- Intravenous Fluids
- Vasopressors as needed (e.g. Norepinephrine)
- Consider Intralipid in refractory shock
- Neuroleptic Malignant Syndrome (rare)
- Disposition
- Asymptomatic patient and normal Electrocardiogram at 6 hours requires no further telemetry monitoring
VII. References
- Otter and Tomaszewski (2018) Crit Dec Emerg Med 32(8): 32