Treatment for Hydroxyzine Overdose
The treatment for hydroxyzine overdose includes immediate gastric lavage if spontaneous vomiting has not occurred, supportive care with vital sign monitoring, ECG monitoring for QT prolongation, management of hypotension with IV fluids and levarterenol or metaraminol (avoiding epinephrine), and seizure control if needed. 1
Initial Management
Gastrointestinal decontamination:
- Induce vomiting if it has not occurred spontaneously
- Perform immediate gastric lavage
- Note: These measures are most effective when performed early after ingestion
Vital signs monitoring:
- Frequent monitoring of vital signs
- Close observation of the patient for clinical deterioration
- ECG monitoring (hydroxyzine overdose can cause QT prolongation and Torsade de Pointes) 1
Supportive Care
Cardiovascular support:
- For hypotension: Administer IV fluids
- If vasopressors needed: Use levarterenol or metaraminol
- IMPORTANT: Do not use epinephrine as hydroxyzine counteracts its pressor action 1
Neurological management:
- For seizures: Administer anticonvulsants
- For severe CNS depression: Provide respiratory support as needed
- Monitor for coma, which is a common manifestation in severe cases 2
Special Considerations
QT interval monitoring:
- Continuous cardiac monitoring is recommended due to risk of QT prolongation
- Watch for development of Torsade de Pointes 1
Respiratory support:
- Monitor for respiratory depression
- Provide ventilatory support if needed (severe cases may require intubation) 2
Clinical Manifestations to Monitor
- Hypersedation (most common manifestation)
- Convulsions/seizures
- Stupor or coma
- Nausea and vomiting
- Sinus tachycardia
- QT prolongation 1, 3
Important Distinctions
Hydroxyzine overdose typically presents with:
- More sedation and CNS depression
- Fewer antimuscarinic effects compared to other antihistamines like diphenhydramine 2
- Patients are more likely to have mild central nervous system depression than a full antimuscarinic toxidrome 2
Treatment Limitations
- There is no specific antidote for hydroxyzine overdose 1
- Hemodialysis is generally not effective for hydroxyzine removal but may be indicated if other substances (e.g., barbiturates) were co-ingested 1
- No practical method exists to quantitate hydroxyzine in body fluids or tissues after ingestion 1
Prognosis
With appropriate supportive care, complete recovery is possible. Mortality from hydroxyzine overdose alone is rare (0.02-0.8% in reported cases) 2, though the clinical course may require several days of supportive care in severe cases.