Recommended Cetirizine Dosage for Allergies
For adults and children 6 years and over, the recommended dose of cetirizine for allergies is 10 mg once daily. 1
Adult Dosing
- Standard dose: 10 mg once daily 1
- For less severe symptoms: 5 mg once daily may be appropriate 1
- Maximum dose: Do not exceed 10 mg in 24 hours 1
Pediatric Dosing
- Children 6 years and older: 10 mg once daily 1
- Children 2-5 years: 5 mg (half the adult dose) once daily 2, 3
- Infants 6-11 months: Consult a doctor; studies have used 0.25 mg/kg twice daily 4
- Children under 6 years: Consult a doctor before use 1
Special Populations
Renal Impairment
- Moderate renal impairment: Reduce dose by 50% (5 mg once daily) 5, 2
- Severe renal impairment (creatinine clearance <10 mL/min): Avoid use 5, 2
Hepatic Impairment
- No specific dose adjustment required for mild-moderate hepatic impairment
- Consult a doctor before use in any liver disease 1
Elderly (65 years and older)
- Consult a doctor before use 1
- Consider starting with 5 mg once daily if renal function is compromised
Clinical Efficacy
- Cetirizine 10 mg has been shown to provide significantly greater symptom reduction compared to placebo in both adults and children 6, 7
- Onset of action occurs within 20 minutes and effects persist for 24 hours 8
- No tolerance develops even after one month of daily treatment 8
Important Considerations
- Cetirizine may cause sedation, especially at higher doses, though it's less sedating than first-generation antihistamines 2
- Common side effects include headache, pharyngitis, and abdominal pain 6
- For severe allergic rhinitis, combination therapy with intranasal antihistamines or corticosteroids may provide superior relief 2
Pitfalls to Avoid
- Exceeding the recommended daily dose can increase sedation without significantly improving efficacy
- Failing to adjust dosage in patients with renal impairment can lead to drug accumulation
- Not recognizing that cetirizine may be sedating for some individuals, affecting driving or tasks requiring alertness
- Overlooking the need for dose reduction in children under 6 years of age
Cetirizine is effective for various allergic conditions including seasonal and perennial allergic rhinitis, as well as urticaria, with a well-established safety profile across different age groups when used at appropriate doses.