Cetirizine Dosing in Infants (6–24 Months)
For infants aged 6–24 months, cetirizine oral suspension should be dosed at 0.25 mg/kg twice daily (approximately 2.5 mg twice daily for most infants in this age range), and it is contraindicated in infants under 6 months of age. 1, 2
Recommended Dosing
Infants 6–11 months: 0.25 mg/kg administered orally twice daily 2
- In clinical trials, this resulted in a mean daily dose of approximately 4.5 mg (±0.7 mg SD) 2
Infants 12–24 months: 0.25 mg/kg administered orally twice daily 3, 4
Contraindications and Precautions
Age restriction: The FDA labeling indicates that children under 6 years of age should "ask a doctor" before use, reflecting the need for physician guidance in this age group 1
Renal impairment: The dose should be halved in infants with moderate renal impairment (creatinine clearance 10–20 mL/min), and cetirizine should be avoided entirely in severe renal impairment (creatinine clearance <10 mL/min) 5
Hepatic impairment: Use with caution, though cetirizine is not specifically contraindicated in hepatic disease unlike some other antihistamines 5
Safety Profile in Infants
Cetirizine has an excellent safety profile in infants, with no significant adverse effects compared to placebo. 2
The first randomized, double-blind, placebo-controlled study specifically in infants (6–11 months) demonstrated no differences in all-cause or treatment-related adverse events between cetirizine and placebo groups 2
A trend toward fewer adverse events and sleep-related disturbances was observed in the cetirizine group compared to placebo 2
No cardiac effects (QT prolongation) were observed in cetirizine-treated infants 2
Long-term safety (18 months) has been established in infants 12–24 months with atopic dermatitis, showing no adverse effects on physical development, psychomotor milestones, or routine laboratory tests 3, 4
Clinical Context
Second-generation antihistamines like cetirizine are strongly preferred over first-generation antihistamines in young children due to their superior safety profile. 6
The 2008 rhinitis practice parameter specifically notes that second-generation antihistamines (cetirizine, desloratadine, fexofenadine, levocetirizine, loratadine) have been shown to be well tolerated with very good safety profiles in young children 6
In contrast, first-generation antihistamines and OTC cough/cold medications should generally be avoided in children below 6 years of age due to potential toxicity, with 54 decongestant-related and 69 antihistamine-related fatalities reported in children ≤6 years between 1969–2006 6
Common Pitfalls to Avoid
Do not use cetirizine in infants under 6 months of age – no safety data exists for this population 1, 2
Avoid weight-based dosing errors – ensure accurate weight measurement and calculation of 0.25 mg/kg per dose 2
Do not combine with other antihistamines – cetirizine monotherapy is sufficient and combination therapy increases risk without proven benefit 4
Adjust for renal impairment – failure to reduce dosing in renal disease can lead to accumulation 5