What is the recommended dosing of hydroxyzine (antihistamine) syrup in children?

Hydroxyzine Syrup Dosing in Children

The recommended dosing of hydroxyzine syrup in children under 6 years is 50 mg daily in divided doses, and for children over 6 years, 50 to 100 mg daily in divided doses. 1

Age-Based Dosing Guidelines

• For children under 6 years of age: 50 mg total daily dose, divided into multiple doses throughout the day 1
• For children over 6 years of age: 50-100 mg total daily dose, divided into multiple doses throughout the day 1
• For sedation as premedication: 0.6 mg/kg of body weight 1

Indications for Use in Children

Hydroxyzine can be prescribed for several conditions in pediatric patients:

• Management of pruritus (itching) due to allergic conditions such as:
  • Chronic urticaria (hives) 1
  • Atopic and contact dermatoses 1
  • Histamine-mediated pruritus 1
• Anxiety and tension relief 1
• Sedation when used as premedication 1, 2
• Anxiolytic use for procedures such as imaging studies 2

Clinical Considerations

Efficacy

• In children with atopic dermatitis, hydroxyzine has shown significant suppression of pruritus from 1 to 24 hours after administration, with greater than 85% suppression from 2 to 12 hours 3
• Lower doses (0.7 mg/kg three times daily) have been shown to be as effective as higher doses (1.4 mg/kg three times daily) in relieving pruritus while causing significantly less sedation 3

Administration Tips

• Dosage should be adjusted according to the patient's response to therapy 1
• When treatment is initiated by the intramuscular route, subsequent doses may be administered orally 1
• Hydroxyzine is available in syrup form which facilitates administration to children 2

Special Populations

• Reduce dose in patients with renal impairment - the dose of hydroxyzine should be halved 2
• Avoid in patients with severe hepatic impairment as it should be avoided in severe liver disease due to its sedating effects 2

Adverse Effects

• The most common side effect is sedation/drowsiness 4
• A recent population-based study suggests caution with long-term use in preschool children, as there may be associations with neurodevelopmental effects 5
• When used in combination with other sedatives, monitor for excessive sedation 6

Monitoring

• Monitor for sedation, especially when used at higher doses 3
• Assess efficacy of symptom relief to determine if dose adjustment is needed 1

Practical Dosing Algorithm

1. Determine the child's age:

   • Under 6 years: Start with 50 mg total daily dose divided into 3-4 doses 1
   • Over 6 years: Start with 50 mg total daily dose, may increase to 100 mg total daily dose if needed, divided into 3-4 doses 1

2. For pruritus treatment:

   • Consider weight-based dosing of 0.7 mg/kg three times daily for optimal antipruritic effect with minimal sedation 3

3. For premedication/sedation:

   • Use 0.6 mg/kg as a single dose 1

4. Adjust dosing based on:

   • Clinical response 1
   • Presence of side effects, particularly sedation 3
   • Renal or hepatic function 2

5. Duration of therapy:

   • Use for the shortest duration possible, especially in preschool-aged children 5

Cautions

• Hydroxyzine is contraindicated during early stages of pregnancy 2
• Long-term use in preschool children should be approached with caution due to potential neurodevelopmental concerns 5
• Always consult relevant product data sheets before prescribing for younger children, as dosing and age restrictions may vary 2