Is cetirizine (antihistamine) safe for use in children under 2 years old?

Cetirizine Safety in Children Under 2 Years Old

Cetirizine should NOT be given to infants under 6 months of age, but it is safe and well-tolerated in infants 6 months to under 2 years old at a dose of 0.25 mg/kg twice daily (approximately 4.5 mg/day). 1

Age-Specific Safety Thresholds

The critical age cutoff is 6 months, which represents a clinically meaningful safety boundary:

• Under 6 months: Cetirizine is NOT recommended due to lack of safety data and regulatory restrictions 1, 2
• 6-11 months: Safe at 0.25 mg/kg twice daily (mean dose ~4.5 mg/day) 1, 3
• 12-23 months: Safe at standard pediatric dosing 1
• 2 years and older: Well-established safety and efficacy 4

Evidence Supporting the 6-Month Threshold

The safety profile in infants 6-11 months is supported by the first randomized, double-blind, placebo-controlled study of any antihistamine in this age group, which demonstrated:

• No difference in adverse events between cetirizine and placebo 3
• A trend toward fewer sleep-related disturbances with cetirizine compared to placebo 3
• No cardiac effects (QT prolongation) 3
• Safety profile similar to placebo in this age range 5

Why Not Under 6 Months?

Historical safety data reveals concerning risks with antihistamines in very young children:

• Between 1969-2006, antihistamines caused 69 deaths in children ≤6 years, with 41 deaths occurring in children under 2 years 1
• These fatalities were primarily associated with first-generation antihistamines, but the FDA advisory position recommends against OTC cough/cold medications (including antihistamines) in children under 6 years 1
• The lack of prospective safety data in infants under 6 months necessitates caution 2, 3

Recommended Alternatives for Infants Under 6 Months

For infants who do not meet the 6-month age threshold:

• First-line: Non-pharmacologic approaches including allergen avoidance and supportive care 1, 2
• If medication necessary: Intranasal corticosteroids are the most effective medication class for allergic rhinitis, controlling all four major symptoms (sneezing, itching, rhinorrhea, nasal congestion) 1

Critical Dosing and Safety Considerations

Standard Dosing (6 months to <2 years)

• 0.25 mg/kg twice daily (approximately 4.5 mg/day total) 1, 3

Renal Impairment Adjustments

• Moderate impairment (CrCl 10-20 mL/min): Reduce dose by 50% 1, 2, 4
• Severe impairment (CrCl <10 mL/min): Avoid cetirizine entirely 1, 2, 4
• Routine renal function testing is not required in healthy infants, but consider baseline assessment if prolonged use (>6 months) is planned 2

Common Pitfalls to Avoid

• Do not assume all second-generation antihistamines have identical safety profiles – age-appropriate safety data must be verified for each specific agent 1, 2
• Avoid combining cetirizine with other sedating medications due to additive CNS depression effects 1, 2
• Do not confuse cetirizine with first-generation antihistamines (diphenhydramine, brompheniramine, chlorpheniramine), which have significantly higher sedation risks and were responsible for the historical fatalities 4
• Always consult product labeling for specific age restrictions, as formulations and country-specific approvals vary (US FDA approves ≥6 months; European approval is ≥2 years) 2, 6

Additional Benefits in This Age Group

Beyond symptom relief, cetirizine in infants with atopic dermatitis sensitized to allergens (grass pollen or house dust mite) provides:

• Reduced risk of asthma development – cetirizine halved the number of patients developing asthma in sensitized subgroups 2
• Corticosteroid-sparing effect in infants with severe atopic dermatitis 5