What is the maximum dose of hydroxyzine (antihistamine) for a 5-year-old child weighing 30 kilograms?

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Maximum Hydroxyzine Dose for a 5-Year-Old, 30 kg Child

For a 5-year-old child weighing 30 kg, the maximum daily dose of hydroxyzine is 50-100 mg per day in divided doses, which translates to approximately 1.7-3.3 mg/kg/day. 1

FDA-Approved Dosing Guidelines

The FDA label provides clear dosing parameters based on age rather than weight for hydroxyzine in children 1:

  • Children under 6 years: 50 mg daily in divided doses (for all indications including anxiety, tension, and pruritus) 1
  • Children over 6 years: 50-100 mg daily in divided doses 1

Since this child is 5 years old, they fall into the "under 6 years" category, making 50 mg per day the maximum recommended dose regardless of their 30 kg weight 1.

Weight-Based Considerations

For premedication/sedation purposes, the FDA label specifies a weight-based dose of 0.6 mg/kg 1. For a 30 kg child, this would equal 18 mg per dose. However, this is specifically for single-dose sedation use, not for chronic administration 1.

Clinical Context from Research

A pharmacokinetic study in children with atopic dermatitis demonstrated that 0.7 mg/kg three times daily (total daily dose of 2.1 mg/kg/day) was as effective as higher doses and caused significantly less sedation 2. For a 30 kg child, this would be approximately 21 mg three times daily (63 mg/day total) 2.

However, the FDA-approved maximum of 50 mg/day for children under 6 years should not be exceeded 1, even though the child's weight might theoretically support a higher dose based on mg/kg calculations.

Critical Safety Considerations

  • Sedation is the primary dose-limiting adverse effect in children, with higher doses causing significantly more sedation without additional therapeutic benefit 2
  • Renal impairment requires a 50% dose reduction, and severe renal impairment (creatinine clearance <10 mL/min) is a contraindication 3
  • Hepatic disease is a contraindication due to inappropriate sedating effects and risk of precipitating hepatic complications 3
  • Hydroxyzine is available in syrup form to facilitate pediatric administration 3

Common Pitfalls to Avoid

  • Do not calculate pediatric doses by simply scaling adult doses by weight 4 - this results in doses that are too large for neonates and potentially inappropriate for young children 4
  • Do not exceed the age-based maximum even if weight-based calculations suggest a higher dose would be appropriate 1
  • Do not use during early pregnancy (contraindicated) 3
  • Avoid in severe hepatic or renal disease 3

Practical Dosing Algorithm

For this specific 5-year-old, 30 kg child:

  1. Start with 12.5-16.7 mg three times daily (37.5-50 mg total daily dose) 1
  2. Maximum daily dose: 50 mg (divided into 2-4 doses throughout the day) 1
  3. Adjust based on response and sedation, but never exceed 50 mg/day for a child under 6 years 1
  4. Monitor for excessive sedation, which indicates the need for dose reduction 2

References

Guideline

Hydroxyzine Dosing Considerations

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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