What is the recommended dosage of hydroxyzine (antihistamine) for children?

Hydroxyzine Dosing in Children

For children under 6 years, hydroxyzine should be dosed at 50 mg total daily in divided doses; for children over 6 years, 50-100 mg total daily in divided doses, according to FDA labeling. 1

Standard Dosing by Age and Indication

For Anxiety and Tension

• Children under 6 years: 50 mg total daily in divided doses 1
• Children over 6 years: 50-100 mg total daily in divided doses 1
• Adults (for reference): 50-100 mg four times daily 1

For Pruritus (Allergic Conditions, Urticaria, Atopic Dermatitis)

• Children under 6 years: 50 mg total daily in divided doses 1
• Children over 6 years: 50-100 mg total daily in divided doses 1
• Adults (for reference): 25 mg three to four times daily 1

For Premedication/Sedation

• Children: 0.6 mg/kg of body weight 1
• Adults (for reference): 50-100 mg 1

Evidence-Based Weight-Based Dosing

Research supports 0.7 mg/kg three times daily as an effective and well-tolerated dose for pruritus in children with atopic dermatitis, with significantly less sedation than higher doses (1.4 mg/kg three times daily) while maintaining equivalent efficacy 2. This pharmacokinetic study in children (mean age 6.1 years) demonstrated peak serum concentrations at 2 hours with an elimination half-life of 7.1 hours, providing pruritus suppression for up to 24 hours 2.

Critical Dosing Adjustments

Renal Impairment

• Moderate to severe renal impairment: Reduce dose by 50% 3, 4
• Severe renal impairment (creatinine clearance <10 mL/min): Avoid hydroxyzine entirely 3, 4

Hepatic Impairment

• Severe liver disease: Avoid hydroxyzine due to inappropriate sedating effects and risk of precipitating hepatic complications 3, 4

Administration Considerations

• Formulation: Hydroxyzine is available in syrup form, facilitating administration to children 4
• Transition from IM to oral: When treatment is initiated intramuscularly, subsequent doses may be administered orally 1
• Dose adjustment: Dosage should be adjusted according to the patient's response to therapy 1

Safety Warnings and Precautions

Pregnancy and Lactation

• Pregnancy: Hydroxyzine is specifically contraindicated during early pregnancy in U.K. manufacturer guidelines—it is the only antihistamine with this specific contraindication 3
• Lactation: Avoidance or caution is recommended 3

Long-Term Use Concerns

A population-based longitudinal study found that repeat prescriptions of hydroxyzine (compared to single prescriptions) were associated with increased rates of neurodevelopmental disorders by age 10, including tic disorders (OR 1.55), anxiety (OR 1.34), and conduct disturbances (OR 1.34) 5. This suggests using the shortest possible duration of hydroxyzine in preschool-age children 5.

Sedation Profile

• The primary adverse effect is sedation 2
• Adding hydroxyzine at night (10-50 mg) to a non-sedating antihistamine during the day may help sleep but provides little additional clinical effect on urticaria if H1 receptors are already saturated 3
• Sedation is dose-dependent, with 0.7 mg/kg three times daily causing significantly less sedation than 1.4 mg/kg three times daily 2

Age Restrictions

None of the currently licensed antihistamines is contraindicated in children 12 years and older 3. For younger children, dosing and age restrictions vary by product, requiring consultation of specific product data sheets 3.

Common Pitfalls to Avoid

• Do not use adult dosing formulas for children—the FDA provides specific pediatric dosing that differs substantially from adult regimens 1
• Do not continue long-term without reassessing necessity, given emerging neurodevelopmental concerns with prolonged use in young children 5
• Do not forget renal dose adjustment—failure to halve the dose in renal impairment increases toxicity risk 3, 4
• Do not use in severe hepatic disease—the sedating effect is particularly inappropriate in this population 3