What are the approved ages and recommended dosing regimens for Zyrtec (cetirizine) in children?

Cetirizine (Zyrtec) Approved Ages and Dosing in Children

Cetirizine is FDA-approved for children 6 months and older in the United States, not just children over 1 year old, with specific weight-based dosing for infants 6-11 months and age-based dosing for older children. 1, 2, 3

FDA-Approved Age Ranges and Dosing

Infants 6-11 Months

• Cetirizine 0.25 mg/kg administered twice daily (approximately 2.5 mg twice daily for a 10 kg infant) 1, 2, 4
• This represents the youngest FDA-approved age group for cetirizine use 1
• Safety has been documented in prospective, randomized, double-blind, placebo-controlled studies specifically in this age group 4

Children 12-23 Months (1-2 Years)

• 2.5 mg twice daily (total daily dose: 5 mg) 1, 2
• Liquid formulations are strongly preferred for easier administration and better absorption 1, 2

Children 2-5 Years

• 2.5 mg once or twice daily depending on symptom severity 1, 2, 5
• Maximum daily dose: 5 mg 2

Children 6 Years and Older

• 5-10 mg once daily 3, 6
• The 10 mg dose provides more effective symptom control than 5 mg for seasonal allergic rhinitis 6
• FDA labeling states: "one 10 mg tablet once daily; do not take more than one 10 mg tablet in 24 hours" 3

Critical Safety Profile

Cetirizine is one of only two antihistamines (along with loratadine) with FDA approval for children younger than 5 years, making it the preferred choice over first-generation antihistamines. 1, 2

Documented Safety Evidence

• The 18-month ETAC study in 817 children aged 12-24 months demonstrated no clinically relevant differences in neurologic symptoms, cardiovascular effects, growth, behavioral assessments, or laboratory values compared to placebo 7
• No QTc interval prolongation was observed in cetirizine-treated infants 4, 7
• Adverse events were actually less common in cetirizine-treated children than placebo, though not statistically significant 7

Contraindicated Alternatives

First-generation antihistamines (diphenhydramine, hydroxyzine) should never be prescribed for routine allergic symptoms in children under 6 years. 1, 2

• Between 1969-2006,69 deaths in children under 6 years were linked to antihistamine exposure, with diphenhydramine responsible for 33 deaths in children under 2 years 1, 2, 8
• The FDA and American Academy of Pediatrics explicitly recommend against OTC cough-and-cold products containing first-generation antihistamines in children under 6 years 1, 2

Clinical Context and Treatment Algorithm

First-Line Therapy Hierarchy

1. Intranasal corticosteroids are the most effective medication class for controlling all symptoms of allergic rhinitis in children, including those under 2 years 1
2. Cetirizine serves as second-line or adjunctive therapy when intranasal corticosteroids alone are insufficient 1

Appropriate Clinical Uses

• Seasonal allergic rhinitis 6, 9
• Chronic spontaneous urticaria 9
• Atopic dermatitis-associated symptoms (though not for prevention of wheezing/asthma) 2, 7

Inappropriate Uses to Avoid

• Never use antihistamines "to make a child sleepy" - this is explicitly contraindicated per FDA labeling 1, 2
• Do not use for prevention of wheezing or asthma in infants with atopic dermatitis, as risks outweigh uncertain benefits 2
• Avoid OTC combination cough-and-cold products in children under 6 years due to overdose risk 1, 2

Common Pitfalls

Do not combine cetirizine with topical diphenhydramine - this significantly increases overdose risk causing excessive sedation, seizures, and cardiac arrhythmias 8

For localized skin symptoms requiring topical therapy, use topical corticosteroids instead of topical antihistamines. 8

Sedation is uncommon at recommended cetirizine doses, but monitor when higher doses are used. 1