Cetirizine Dosing for a 50-Pound Child
For a child weighing 50 pounds (approximately 23 kg), administer 5 mL of Zyrtec (cetirizine) 1 mg/mL oral solution once daily, providing a total dose of 5 mg. 1
Weight-Based Dosing Calculation
- A 50-pound child equals approximately 22.7 kg
- The standard pediatric dose for children in this weight range is 5 mg once daily 1, 2
- With a 1 mg/mL concentration, this translates to 5 mL once daily 1
Age Considerations
- This dosing applies to children aged 6 years and older 2
- For children aged 2-5 years in this weight range, the same 5 mg (5 mL) once daily dose is appropriate 1, 3
- Children under 2 years require twice-daily dosing due to rapid oral clearance, but a 50-pound child would typically be older than 2 years 1
Important Safety Considerations
Sedation Risk:
- Cetirizine may cause sedation at recommended doses, with higher incidence in older children (13.7%) compared to placebo (6.3%) 1
- Counsel caregivers about potential drowsiness, particularly regarding school activities 1
- The sedation risk is milder than first-generation antihistamines but greater than fexofenadine or loratadine 1
Renal Impairment:
- If the child has moderate renal impairment, reduce the dose by 50% to 2.5 mg (2.5 mL) once daily 1
- Avoid cetirizine in severe renal impairment (creatinine clearance <10 mL/min) 1
Clinical Efficacy
- The 5 mg dose provides effective symptom control for seasonal allergic rhinitis in children aged 6-11 years, though 10 mg showed superior efficacy in clinical trials 2
- Onset of action occurs within 20 minutes, with effects persisting for 24 hours 4
- No tolerance develops even after 1 month of daily treatment 4