Cetirizine Side Effects
Cetirizine may cause mild drowsiness at recommended doses, with approximately 13.7% of patients experiencing sedation compared to 6.3% with placebo. 1
Common Side Effects
- Sedation/Drowsiness: Cetirizine has more sedative properties than some other second-generation antihistamines (fexofenadine, loratadine, desloratadine) at recommended doses 1
- Mild CNS effects: While less sedating than first-generation antihistamines, cetirizine can still cause drowsiness without necessarily impairing performance at standard doses 1
- Dry mouth: More commonly reported with cetirizine than with placebo 2
- Headache, pharyngitis, and abdominal pain: Reported in pediatric studies but at rates similar to placebo 3
Comparison to Other Antihistamines
Sedation spectrum: Cetirizine falls in the middle of the sedation spectrum among second-generation antihistamines 1:
- Non-sedating at recommended doses: fexofenadine, loratadine, desloratadine
- May cause sedation at recommended doses: cetirizine, intranasal azelastine
- Highly sedating: first-generation antihistamines (diphenhydramine, chlorpheniramine)
Anticholinergic effects: Cetirizine has minimal anticholinergic activity compared to first-generation antihistamines, though dry mouth has been reported 2
Dosage-Related Side Effects
- Standard dose (10 mg) may cause mild drowsiness (13.7% vs 6.3% for placebo) without performance impairment 1
- Higher doses (20 mg or greater) may cause more significant drowsiness and potential performance impairment 1
- Four-fold dose (40 mg daily) significantly improves symptoms but with increased sedative effects 1
Special Populations
Pediatric Considerations
- School-age children may experience negative effects on school performance if sedation occurs 1
- Most common side effects in children 6-11 years include headache, pharyngitis, and abdominal pain at rates similar to placebo 3
- In overdose cases, drowsiness and sedation are the primary effects observed 4
Elderly Considerations
- Older adults may be more sensitive to sedative effects 1
- Cetirizine is generally well-tolerated by elderly patients 5
Safety Profile
- No cardiac adverse effects reported 6, 2
- Low potential for drug interactions as it has minimal effect on hepatic cytochrome P450 system 6
- Primarily eliminated by the kidneys with a mean elimination half-life of 8.3 hours 2
- No evidence of tolerance developing even after one month of daily treatment 2
Management of Side Effects
- If drowsiness occurs, consider administering cetirizine in the evening 7
- For persistent sedation, consider switching to a less sedating antihistamine like fexofenadine or loratadine 1
- In cases of pruritus (itching) potentially caused by other medications, cetirizine may actually be beneficial as a treatment 1