What is the maximum daily dose of cetirizine for adults, children aged ≥6 years, children 2–5 years, and patients with moderate to severe renal impairment?

Maximum Daily Dose of Cetirizine

For adults and children ≥6 years, the standard maximum dose is 10 mg once daily, though doses up to 40 mg daily may be used in refractory cases under specialist guidance. 1

Standard Dosing by Age Group

Adults and Children ≥6 Years

• Maximum standard dose: 10 mg once daily 1
• For refractory urticaria or allergic conditions not responding to standard dosing, the British Association of Dermatologists supports dose escalation up to 40 mg daily in divided doses (Quality of evidence III, Strength of recommendation C) 1
• This higher dosing is considered off-label but may be necessary for adequate symptom control in non-responders 1, 2

Children Aged 2–5 Years

• Maximum dose: 5 mg per day 3
• Start with 2.5 mg once daily (approximately 2.5 mL syrup); if symptoms remain uncontrolled after 3–5 days, escalate to 5 mg once daily or split into two 2.5 mg doses 3
• Do not exceed 5 mg daily in this age group, as higher doses increase sedation risk without additional benefit 3

Infants 6–11 Months

• Cetirizine is available as oral drops for precise dosing in this age group 1
• Specific maximum dosing requires weight-based calculation; twice-daily dosing is typically necessary due to rapid oral clearance in very young children 3

Renal Impairment Adjustments

Moderate Renal Impairment (CrCl 10–50 mL/min)

• Reduce dose by 50% to 5 mg once daily 1, 3
• Cetirizine is predominantly eliminated renally with a mean half-life of 8.3 hours, making dose reduction essential 1, 4

Severe Renal Impairment (CrCl <10 mL/min)

• Cetirizine should be avoided entirely 1
• The drug is ineffective and not recommended for hemodialysis patients 1

Important Safety Considerations

Sedation Risk

• In patients ≥12 years, cetirizine causes sedation in approximately 13.7% versus 6.3% with placebo 3
• The sedation incidence is lower in younger children but still present 3
• If significant drowsiness occurs, reduce to 2.5 mg once daily or switch to a non-sedating antihistamine (loratadine or fexofenadine) 3
• Consider evening dosing to minimize daytime sedation and prevent negative effects on school performance 1

Common Pitfalls to Avoid

• Never use first-generation antihistamines or OTC cough/cold combination products in children <6 years due to lack of efficacy and serious safety risks including fatal overdose 3
• Do not combine cetirizine with other sedating medications without considering additive CNS effects 1
• In low-weight children, use standard age-based dosing rather than weight-based calculations to avoid inadvertent over-dosing and increased sedation 3

Pregnancy and Drug Interactions

• Cetirizine is FDA Pregnancy Category B; avoid use especially in the first trimester unless clearly necessary 1, 3
• No significant drug interactions or cardiac adverse effects (including QT prolongation) have been documented 4, 2