What are the side effects of hydroxyzine and how can they be managed?

Side Effects of Hydroxyzine and Their Management

Hydroxyzine commonly causes sedation, drowsiness, performance impairment, and anticholinergic effects that can significantly impact quality of life, and these side effects should be carefully managed through dosing strategies, patient education, and consideration of alternative medications when appropriate. 1

Common Side Effects

Central Nervous System Effects

• Sedation and drowsiness (occurs in up to 80% of patients) 1
• Performance impairment (occurs even without subjective awareness of drowsiness) 1, 2
• Impaired learning and school performance in children 1
• Impaired driving ability (1.5× higher risk of fatal accidents) 1
• Occupational accidents and decreased work productivity 1

Anticholinergic Effects

• Dry mouth and eyes 1, 3
• Constipation 3
• Urinary retention (inhibition of micturition) 1
• Increased risk of narrow-angle glaucoma 1

Cardiovascular Effects

• QT prolongation 3
• Risk of Torsade de Pointes (rare but serious) 3

Other Side Effects

• Headache 3
• Hallucinations (rare) 3
• Skin reactions: pruritus, rash, urticaria 3
• Acute Generalized Exanthematous Pustulosis (AGEP) and fixed drug eruptions (rare) 3
• Irritability 1, 2

Management Strategies

Dosing Strategies

1. Evening/bedtime dosing

   • Administering hydroxyzine as a single bedtime dose rather than divided doses can minimize daytime sedation and performance impairment 4
   • This maintains skin H1-receptor antagonism the following morning while reducing daytime side effects 4

2. Start with low doses

   • Begin with lower doses, especially in elderly or frail patients 1
   • Gradually titrate to effective dose to minimize side effects 5

Patient Education

• Warn patients about the risk of sedation and performance impairment 1
• Advise against driving or operating machinery until individual response is known 1
• Inform patients that performance can be impaired even without feeling drowsy 1, 2
• Caution against concomitant use of:
  • Alcohol
  • Other CNS depressants
  • Sedatives
  • Hypnotics
  • Antidepressants 1

Special Populations

Elderly Patients

• Use with extreme caution due to:
  • Increased sensitivity to psychomotor impairment
  • Higher risk of falls and complications (fractures, subdural hematomas)
  • Greater susceptibility to anticholinergic effects
  • Potential worsening of cognitive impairment 1, 6
• Consider lower doses (e.g., 10-25 mg) 1

Children

• Monitor for potential impact on learning and school performance 1
• Consider alternative non-sedating antihistamines for daytime use 6

Patients with Comorbidities

• Cardiovascular disease: Monitor ECG in patients at risk for QT prolongation 3
• Glaucoma: Avoid in narrow-angle glaucoma 1
• Prostatic hypertrophy: Use caution due to anticholinergic effects 1
• Renal/hepatic impairment: Use lower doses and monitor closely 6

Alternative Medications

• Consider second-generation antihistamines (cetirizine, loratadine, fexofenadine) for allergic conditions, which have less sedation and fewer anticholinergic effects 1, 6
• For anxiety, consider SSRIs, SNRIs, or buspirone as alternatives with fewer side effects 6, 7

Management of Overdose

• Induce vomiting if not spontaneous
• Perform gastric lavage
• Provide supportive care with monitoring of vital signs
• ECG monitoring for QT prolongation
• Treat hypotension with IV fluids and levarterenol or metaraminol (do not use epinephrine) 3

Monitoring

• Monitor for signs of excessive sedation
• In patients with cardiovascular risk factors, consider ECG monitoring
• Assess for anticholinergic side effects, particularly in elderly patients
• Evaluate impact on daily functioning, work performance, and quality of life

By implementing these management strategies, the side effects of hydroxyzine can be minimized while maintaining its therapeutic benefits. When side effects persist despite management strategies, consider switching to alternative medications with more favorable side effect profiles.