At what age can cetirizine be started in children?

Starting Age for Cetirizine in Children

Cetirizine can be started at 6 months of age, with a dose of 0.25 mg/kg twice daily (approximately 2.5 mg twice daily for a typical infant). 1, 2

Age-Specific Dosing Guidelines

Infants 6-11 Months

• Approved starting age: 6 months in the United States 1, 3
• Dose: 0.25 mg/kg twice daily (approximately 2.5 mg twice daily for a 10 kg infant) 1, 2
• This dosing has been validated in prospective, randomized, double-blind, placebo-controlled studies specifically in this age group 2

Children 12-23 Months

• Continue 0.25 mg/kg twice daily 4
• Long-term safety (up to 18 months) has been established in children with atopic dermatitis starting at 12-24 months of age 4

Children 2-5 Years

• Dose: 2.5 mg once or twice daily 1, 5
• This is the European approval age (2 years and older) 3

Children 6 Years and Older

• Dose: 5-10 mg once daily 6, 7
• The 10 mg dose provides significantly better symptom control than 5 mg for seasonal allergic rhinitis 7

Critical Safety Considerations

Do NOT Use Below 6 Months

• Cetirizine is not recommended for infants under 6 months of age 8
• British guidelines specifically advise consulting product labeling and avoiding use below 6 months 8
• The one-month difference between 5 and 6 months is clinically significant due to lack of safety data 8

Safety Profile in Approved Age Groups

• In infants 6-11 months, cetirizine showed a safety profile similar to placebo with no increase in adverse events 2
• No cardiac effects (QTc prolongation) were observed in infants 2, 4
• Long-term use (18 months) showed no effects on growth, development, or behavior in children 12-24 months 4

Common Pitfalls to Avoid

Renal Impairment

• Cetirizine requires dose reduction in moderate renal impairment and should be avoided in severe renal impairment due to predominantly renal excretion 8
• Consider baseline renal assessment if prolonged use (>6 months) is planned 8

Avoid First-Generation Antihistamines

• Never use diphenhydramine or other first-generation antihistamines in children under 6 years for routine allergic symptoms 5
• Between 1969-2006, there were 69 deaths associated with antihistamines in children under 6 years, with diphenhydramine responsible for 33 of these deaths 5

Formulation Matters

• Use liquid formulations in young children for easier administration and better absorption 5
• Avoid OTC cough and cold combination products in children under 6 years due to overdose risk 5

Clinical Context for Use

Approved Indications

• Allergic rhinitis (seasonal and perennial) 9, 3
• Chronic idiopathic urticaria 9, 3
• Atopic dermatitis with allergic sensitization (reduces asthma risk in sensitized infants) 8, 9

When Cetirizine Is NOT First-Line

• For severe allergic reactions or anaphylaxis, epinephrine is the only first-line treatment; cetirizine is purely adjunctive 5
• For allergic rhinitis in children under 2 years, intranasal corticosteroids are more effective than antihistamines 1