Cetirizine Dosage for a 4-Year-Old Weighing 45 Pounds
For a 4-year-old child weighing 45 pounds (approximately 20.4 kg), the appropriate dose of cetirizine is 5 mg once daily. 1, 2
Dosage Considerations
- For children aged 2-5 years, cetirizine is typically dosed at 2.5 mg (½ teaspoon) to 5 mg (1 teaspoon) once daily, depending on symptom severity 2
- Weight-based dosing suggests approximately 0.25 mg/kg/day, which would equal about 5 mg daily for a child weighing 45 pounds 3
- The standard pediatric formulation is available as a 5 mg/5 mL (1 teaspoon) oral solution 2
Safety Profile
- Cetirizine is generally well-tolerated in children, with clinical trials showing a safety profile comparable to placebo 4
- The most common side effects reported in children include headache, pharyngitis, and abdominal pain, occurring at rates similar to placebo 2
- Drowsiness may occur in some children taking cetirizine, though it tends to be milder than with first-generation antihistamines 1
Important Considerations
- Cetirizine may cause mild drowsiness in approximately 13.7% of patients compared to 6.3% with placebo 1
- Unlike some other second-generation antihistamines (fexofenadine, loratadine), cetirizine has been associated with some sedative properties even at recommended doses 1
- In case of accidental overdose, the primary symptom is drowsiness, as reported in a case of a 4-year-old who ingested 60 mg (12 times the recommended dose) and experienced sedation that resolved within 5-6 hours without treatment 5
Administration Tips
- Cetirizine can be given with or without food 2
- Once-daily dosing is typically sufficient for symptom control 2
- For younger children with more rapid clearance, twice-daily dosing may occasionally be necessary for optimal symptom control 3
- If drowsiness occurs, consider administering the dose in the evening 1