What are the considerations for using hydroxyzine (an antihistamine) in a healthy 70-year-old woman?

Hydroxyzine Use in a Healthy 70-Year-Old Woman

Hydroxyzine should generally be avoided in a healthy 70-year-old woman due to significantly increased risks of falls, fractures, cognitive impairment, and anticholinergic effects in older adults, with second-generation antihistamines (fexofenadine, loratadine, or desloratadine) being strongly preferred alternatives. 1, 2

Critical Age-Related Safety Concerns

Older adults face disproportionate risks with hydroxyzine that fundamentally alter the risk-benefit calculation:

• Psychomotor impairment is heightened in elderly patients, leading to increased risk of falls, fractures, and subdural hematomas—serious morbidity and mortality outcomes 1, 2
• Anticholinergic effects are more pronounced, including dry mouth, dry eyes, constipation, urinary retention, and increased risk of narrow-angle glaucoma 1, 2
• Sedation persists beyond plasma drug levels, causing next-day impairment even when dosed only at bedtime, with performance impairment occurring without subjective awareness of drowsiness 1, 2
• Comorbid conditions common in older adults (increased intraocular pressure, benign prostatic hypertrophy, preexisting cognitive impairment) amplify these risks 1

FDA-Mandated Warnings Relevant to This Population

• QT prolongation and Torsade de Pointes have been reported, with hydroxyzine requiring caution in patients with heart disease, electrolyte imbalances, recent myocardial infarction, uncompensated heart failure, and bradyarrhythmias 3
• CNS depression is potentiated when used with other CNS depressants, requiring dosage reduction of concomitant medications 3
• Elderly patients should start at low doses due to greater frequency of decreased hepatic, renal, or cardiac function, though the FDA notes sedating drugs may cause confusion and over-sedation in the elderly 3

Driving and Functional Impairment Data

• Drivers taking first-generation antihistamines are 1.5 times more likely to be responsible for fatal automobile accidents compared to control drivers 1
• Recent 2025 data shows hydroxyzine is now the most identified antihistamine in impaired driving investigations, with common observations including incoordination, slow/slurred speech, erratic driving, crashes, and difficulty following instructions 4
• Impaired driving performance with hydroxyzine worsens with cellular phone use 1

Preferred Alternative Approach

If antihistamine therapy is indicated, use this algorithm:

1. First choice: Second-generation non-sedating antihistamines (fexofenadine, loratadine, or desloratadine at recommended doses) 2, 5

   • These do not cause sedation and lack anticholinergic effects 2
   • Multiple options should be tried, as individual responses vary 5

2. If inadequate response: Increase second-generation antihistamine dose up to 4 times standard dose before considering hydroxyzine 5

3. Only if second-generation agents fail and specific indication exists (e.g., severe nocturnal pruritus requiring sedation):

   • Consider hydroxyzine 10-25 mg once daily at bedtime 2
   • Counsel extensively on fall risk, next-day impairment, and driving hazards 1, 2
   • Monitor closely for sedation, falls, confusion, dry mouth, constipation, and urinary retention 2

Renal Dosing Adjustment

• In moderate renal impairment, halve the hydroxyzine dose 2, 5
• The extent of renal excretion has not been fully determined, requiring cautious dose selection 3

Clinical Context Where Hydroxyzine Might Be Considered

The only scenario where hydroxyzine has guideline support in older adults is as nighttime adjunct therapy for urticaria when:

• Second-generation antihistamines at standard or increased doses have failed 5
• Sleep disruption from pruritus is severe 5
• Patient and family understand fall and cognitive risks 1

Even in this limited context, the British Journal of Dermatology emphasizes hydroxyzine is not first-line monotherapy 5

Common Pitfall to Avoid

Do not use an AM/PM dosing strategy (second-generation antihistamine in morning, hydroxyzine at night) to reduce costs while supposedly avoiding daytime drowsiness—this strategy fails because hydroxyzine's metabolites have prolonged half-lives causing significant next-day impairment 1

Absolute Contraindications in This Population

• Severe liver disease 2, 5
• Congenital long QT syndrome or family history of long QT syndrome 3
• Concomitant use of other QT-prolonging medications without cardiology consultation 3
• Concurrent use of multiple CNS depressants 3