What is the recommended dose of hydroxyzine (antihistamine) for a 13-year-old female patient?

Hydroxyzine Dosing for a 13-Year-Old Female

For a 13-year-old female, the recommended hydroxyzine dose is 50-100 mg daily in divided doses, as this patient falls into the "children over 6 years" category per FDA labeling. 1

Standard Dosing by Indication

For Pruritus (Itching/Allergic Conditions)

• Children over 6 years: 50-100 mg daily in divided doses 1
• This can be administered as 12.5-25 mg three to four times daily, or alternatively as a single bedtime dose of 25-50 mg if sedation is desired 2
• The British Journal of Dermatology specifically recommends 10-25 mg four times daily or at bedtime for pruritus management 2

For Anxiety

• Children over 6 years: 50-100 mg daily in divided doses 1
• This typically translates to 12.5-25 mg given 2-4 times daily depending on symptom severity

As Premedication/Sedation

• 0.6 mg/kg of body weight 1
• For an average 13-year-old female (approximately 45-50 kg), this would be approximately 27-30 mg as a single dose

Administration Strategy

Start at the lower end of the dosing range (50 mg daily total) and titrate upward based on response and tolerability. 1 A practical approach would be:

• Initial dosing: 12.5-25 mg twice daily or three times daily (total 25-75 mg/day)
• Nighttime dosing: Consider giving a larger portion at bedtime (25-50 mg) if sedation is beneficial, with smaller daytime doses if needed 2
• Maximum: Do not exceed 100 mg daily in divided doses for this age group 1

Critical Safety Considerations

CNS Depression Warning

• Hydroxyzine causes significant sedation - approximately 80% sedation rates have been documented, higher than other first-generation antihistamines 3
• Warn the patient and family about impaired concentration, drowsiness, and potential impact on school performance 4, 5
• Avoid combining with other CNS depressants (benzodiazepines, opioids, other sedating medications) as this significantly enhances impairment 2, 3

Anticholinergic Effects

• Monitor for dry mouth, urinary retention, and constipation 3
• Use caution if the patient has any underlying conditions that could be worsened by anticholinergic effects 3

Tolerance Development

• Sedation typically appears during the first week but may diminish with continued use 6
• However, objective performance impairment may persist even when subjective drowsiness improves 5

Common Pitfalls to Avoid

1. Do not rely on patient-reported drowsiness as a measure of impairment - studies show no correlation between subjective symptoms and objective performance deficits 5

2. Avoid long-term monotherapy - hydroxyzine is best used short-term (2-4 weeks) or as a nighttime adjunct to non-sedating antihistamines for chronic conditions 3

3. Do not use in patients with renal impairment without dose adjustment - reduce dose by half in moderate renal impairment 2

4. Avoid in early pregnancy - hydroxyzine is contraindicated in early pregnancy 2

5. Monitor for paradoxical reactions - particularly in patients with developmental disorders 7

Dose Adjustment Considerations

Adjust dosing based on patient response rather than using a fixed schedule. 1 The FDA label explicitly states that "dosage should be adjusted according to the patient's response to therapy." 1

• If inadequate response at 50 mg/day after one week, increase to 75-100 mg/day in divided doses
• If excessive sedation occurs, reduce dose or shift more of the daily dose to bedtime only
• Consider switching to a non-sedating antihistamine if daytime functioning is significantly impaired 3