Olanzapine Overdose Management
There is no specific antidote for olanzapine overdose. Management consists of supportive care with airway protection, cardiovascular monitoring, and addressing complications. 1
Clinical Presentation of Olanzapine Overdose
The most common symptoms of olanzapine overdose include:
Severe cases may present with:
Management Algorithm for Olanzapine Overdose
1. Initial Stabilization
- Establish and maintain airway patency 1
- Ensure adequate oxygenation and ventilation 1
- Intubate if GCS is low or airway protection is compromised 4
- Initiate cardiovascular monitoring immediately, including continuous ECG to detect possible arrhythmias 1
2. Decontamination
- Consider activated charcoal if patient presents within 1 hour of ingestion and airway is protected 2
- Gastric lavage is generally not recommended unless in massive ingestion presenting very early 3
3. Supportive Care
- Provide IV fluids for hypotension 3
- Monitor blood glucose levels and treat hyperglycemia if present 4
- Monitor vital signs frequently, as fluctuations between hypertension/hypotension and tachycardia/bradycardia can occur 3
- Monitor for QTc prolongation on ECG 5
4. Management of Specific Complications
- For agitation: Consider low-dose benzodiazepines with caution, as fatalities have been reported with concurrent use of benzodiazepines with high-dose olanzapine 6
- For seizures: Standard anticonvulsant therapy 1
- For hyperthermia: Cooling measures 3
- For metabolic abnormalities: Correct as indicated 4
5. Monitoring
- Continue cardiac monitoring for at least 24 hours in significant overdoses 1
- Monitor for fluctuating mental status, which is characteristic of olanzapine overdose 2
- Monitor for prolonged toxicity, as symptoms may persist for several days in massive overdoses 7
Prognosis
- Most patients recover within 48 hours with supportive care alone, even with moderate to high doses (120-840 mg) 2
- Prolonged ventilatory support may be required in massive overdoses 7
- Fatal outcomes are rare, even with serum concentrations >2500 μg/L 7
Important Considerations and Pitfalls
- Fluctuating mental status is a characteristic finding in olanzapine overdose and requires careful monitoring rather than additional sedation 2
- Caution with benzodiazepines: Fatalities have been reported with concurrent use of benzodiazepines with high-dose olanzapine due to risk of oversedation and respiratory depression 6
- No specific antidote exists for olanzapine overdose 1
- Consider the possibility of multiple drug involvement, especially in intentional overdoses 1
- Contact a Certified Poison Control Center (1-800-222-1222) for the most up-to-date management recommendations 1