Cetirizine Dosage and Usage for Allergic Rhinitis and Urticaria
For adults and children 6 years and older, cetirizine should be administered at a standard dose of 10 mg once daily for allergic rhinitis and urticaria. 1
Adult Dosing
- Standard dose: 10 mg once daily 1, 2
- Timing: Can be taken at any time of day, but consistent timing is recommended
- Duration: Can be used for both short-term symptom relief and long-term management
- Maximum dose: Do not exceed 10 mg daily as warned by FDA 1
Pediatric Dosing
- Children 6 years and older: 10 mg once daily 1, 2
- Children 2-5 years: 5 mg once daily or 2.5 mg twice daily (consult pediatrician)
- Children under 2 years: Consult pediatrician before use 1
Special Populations
Renal Impairment
- Moderate renal impairment: Reduce dose to 5 mg once daily 1
- Severe renal impairment (creatinine clearance <10 mL/min): Avoid use 1
- Always assess baseline renal function before initiating therapy 1
Elderly Patients
- Use with caution in patients 65 years and older 1
- Monitor for increased sedation, particularly when combined with other medications 1
Clinical Efficacy
Cetirizine effectively treats the following symptoms:
- Sneezing
- Rhinorrhea (runny nose)
- Nasal itching
- Ocular symptoms (itchy, watery eyes)
- Urticarial wheals and flares
In controlled studies, cetirizine has demonstrated:
- Rapid onset of action within 1 hour 3
- 36.7% mean reduction in total symptom complex scores versus 12.0% with placebo 3
- Superior efficacy compared to loratadine in direct comparative studies 4, 3
Therapeutic Considerations
For Allergic Rhinitis
- Cetirizine is effective for both seasonal and perennial allergic rhinitis 5, 4
- For severe nasal congestion, consider adding a decongestant, as antihistamines have limited effect on congestion 6
- In patients with concurrent asthma, cetirizine may help relieve upper respiratory symptoms 6
For Urticaria
- Cetirizine is effective for chronic idiopathic urticaria 4
- Once-daily dosing provides 24-hour symptom control 2
Potential Side Effects
- Common: Mild drowsiness (13.7% versus 6.3% with placebo) 1
- Less common: Headache, dry mouth, fatigue
- Performance impairment may occur at doses of 10 mg or higher 1
- Lower incidence of sedation compared to first-generation antihistamines 6
Important Precautions
- Avoid alcohol consumption while taking cetirizine as it may increase sedation
- Use caution when driving or operating machinery, especially during initial treatment
- Monitor for excessive daytime sedation in elderly patients 1
- Not effective for uraemic pruritus in patients on hemodialysis 1
Clinical Pearls
- Continuous treatment is more effective than as-needed use for seasonal or perennial allergic rhinitis 6
- For patients with refractory symptoms, dose titration up to 20 mg daily may provide greater efficacy, though this exceeds standard recommendations 7
- Second-generation antihistamines like cetirizine are generally preferred over first-generation antihistamines due to lower risk of sedation and anticholinergic effects 6
- For patients with both allergic rhinitis and asthma, cetirizine may help manage upper respiratory symptoms but should not replace appropriate asthma medications 6