Can hydroxyzine cause hypotension?

Hydroxyzine and Hypotension: Clinical Implications

Yes, hydroxyzine can cause hypotension, particularly in overdose situations and in susceptible individuals. The FDA drug label explicitly states that hypotension, while unlikely with normal dosing, may occur in overdose scenarios and would require management with intravenous fluids and vasopressors such as levarterenol or metaraminol 1.

Mechanisms and Risk Factors

Hydroxyzine's hypotensive effects are primarily related to:

1. Histamine antagonism: As an antihistamine, hydroxyzine blocks H1 receptors which can lead to vasodilation
2. Central nervous system depression: Causing reduced sympathetic tone
3. Potential cardiac effects: The drug can cause QT prolongation in high doses, which may contribute to hemodynamic instability

Risk factors that increase susceptibility to hydroxyzine-induced hypotension include:

• Elderly patients
• Concurrent use of other sedating medications
• Cardiovascular disease
• Dehydration
• Higher doses

Clinical Presentation and Management

Hypotension from hydroxyzine may present as:

• Orthostatic hypotension (more common)
• Supine hypotension (less common, usually in overdose)
• Associated symptoms: dizziness, lightheadedness, syncope

Management of hydroxyzine-induced hypotension:

1. Discontinue the medication if hypotension occurs

2. Supportive care:

   • Intravenous fluids for volume resuscitation
   • Position patient supine with legs elevated
   • Monitor vital signs frequently

3. For severe hypotension:

   • Use vasopressors if needed - specifically levarterenol or metaraminol
   • Important: Do NOT use epinephrine as hydroxyzine counteracts its pressor action 1
   • ECG monitoring is recommended in overdose cases due to risk of QT prolongation and Torsade de Pointes

Special Considerations

• Drug interactions: Hydroxyzine may enhance hypotensive effects when combined with antihypertensives or other sedating medications
• Elderly patients: Use with caution as they are more susceptible to orthostatic hypotension 2
• Cardiovascular patients: Those with pre-existing cardiovascular disease may be at higher risk for hemodynamic effects

Clinical Recommendations

• Start with lower doses in elderly patients and those with cardiovascular disease
• Monitor blood pressure when initiating therapy, particularly in high-risk patients
• Consider alternative anxiolytics in patients with unstable blood pressure or cardiovascular disease
• Educate patients about potential orthostatic symptoms and precautions (rising slowly from sitting/lying positions)
• Avoid combining with other medications that may potentiate hypotension

While hydroxyzine is generally considered to have limited cardiovascular effects compared to some other psychotropic medications 3, clinicians should remain vigilant about the potential for hypotension, especially in vulnerable populations or overdose situations.