What is the recommended dose of Zyrtec (cetirizine)?

Zyrtec (Cetirizine) Recommended Dosing

For adults and children 6 years and older, the recommended dose of Zyrtec (cetirizine) is 10 mg once daily, with a maximum of one 10 mg dose in 24 hours. 1

Adult Dosing

• Standard dose: 10 mg once daily 1
• Less severe symptoms: 5 mg once daily may be appropriate 1
• Maximum dose: Do not exceed 10 mg in 24 hours 1

Pediatric Dosing by Age

Children 6 years and older

• 10 mg once daily (same as adult dosing) 1
• Clinical trials demonstrate this dose is safe and effective, with significant symptom improvement compared to placebo 2

Children 2-5 years

• 5 mg once daily (2.5 mL of oral solution or half of a 10 mg tablet) 3
• Studies show good efficacy and tolerance in this age group 3

Children 6-11 months

• 0.25 mg/kg twice daily (approximately 4.5 mg total daily dose) 4
• This dosing has been validated in controlled safety studies 4

Children 12-24 months

• 0.25 mg/kg twice daily 5
• Long-term safety confirmed in 18-month prospective studies 5

Special Populations

Elderly (≥65 years)

• Consult a physician before use 1
• Consider dose reduction due to potential decreased renal function with age 6

Renal Impairment

• Moderate impairment (creatinine clearance 10-30 mL/min): Reduce dose by half 6
• Severe impairment (creatinine clearance <10 mL/min): Avoid cetirizine 6

Hepatic Impairment

• Consult a physician before use 1
• Use with caution, though specific dose adjustments are not well-established 6

Administration Considerations

• Can be taken with or without food, though taking with meals may improve gastrointestinal tolerability 7
• Evening dosing may help minimize any sedative effects that occur, particularly with cetirizine which can be more sedating than other second-generation antihistamines 6, 8
• Available formulations: 10 mg tablets, 5 mg/5 mL oral solution, and chewable tablets 1

Common Pitfalls to Avoid

• Do not exceed recommended daily doses - cetirizine can cause sedation, especially at higher doses 6
• Discontinue 6 days before allergy skin testing if using desloratadine; shorter discontinuation periods for cetirizine due to its shorter half-life 6
• Avoid in pregnancy, especially first trimester, though cetirizine is FDA Pregnancy Category B with no evidence of fetal harm 6
• Do not combine with other sedating antihistamines without medical supervision due to additive CNS effects 6

If Inadequate Response

• Consider switching to alternative second-generation antihistamines (fexofenadine, loratadine, desloratadine) rather than increasing cetirizine frequency 9
• Adding montelukast 10 mg to cetirizine 5 mg once daily provides equal efficacy to cetirizine 10 mg with less sedation 9
• Increasing doses above licensed recommendations is common practice when benefits outweigh risks, though this should be done cautiously 6