Treatment for Hydroxyzine Overdose
The treatment for hydroxyzine overdose includes immediate gastric lavage if spontaneous vomiting has not occurred, supportive care with close monitoring of vital signs, ECG monitoring for QT prolongation, and management of specific symptoms such as hypotension with IV fluids and levarterenol or metaraminol (not epinephrine). 1
Initial Management
Gastrointestinal decontamination:
- Induce vomiting if it hasn't occurred spontaneously
- Perform immediate gastric lavage 1
- Note: Most effective if performed soon after ingestion
Vital signs monitoring:
- Frequent monitoring of vital signs is essential
- Close observation of the patient for clinical deterioration 1
Specific Symptom Management
CNS Depression
- Hypersedation is the most common manifestation of hydroxyzine overdose 1
- Supportive care with airway management if needed
- Monitor for respiratory depression which is less common than with diphenhydramine overdoses 2
Cardiovascular Management
- ECG monitoring is recommended due to risk of QT prolongation and Torsade de Pointes 1
- For hypotension:
- Administer IV fluids
- If needed, use levarterenol or metaraminol
- IMPORTANT: Do not use epinephrine as hydroxyzine counteracts its pressor action 1
Seizure Management
- Seizures may occur in severe cases 3
- Administer benzodiazepines for seizure control
- In historical cases, physostigmine has been used for seizure control in hydroxyzine toxicity 3, but this is not currently recommended as standard practice
Important Considerations
- No specific antidote exists for hydroxyzine overdose 1
- Hemodialysis is generally not effective for hydroxyzine removal but may be considered if other substances were co-ingested 1
- Mortality from hydroxyzine overdose is rare (0.02-0.8% in reported cases) 2
- Hydroxyzine-poisoned patients are more likely to have mild CNS depression rather than a full antimuscarinic toxidrome 2
Monitoring and Follow-up
- Continue cardiac monitoring until ECG normalizes
- Monitor for respiratory depression and provide ventilatory support if needed
- Observe for at least 6-8 hours after symptom resolution
- Consider psychiatric evaluation if overdose was intentional
Clinical Pearls
- Unlike diphenhydramine overdose, hydroxyzine overdose presents with fewer antimuscarinic effects 2
- Prolonged monitoring may be necessary as effects can persist for several days in severe cases
- Rare complications like priapism have been reported with hydroxyzine overdose and may require specific interventions 4