Cetirizine adverse effects

Seasonal allergic rhinitis affects about 10% of school-age children, and there is evidence of a significant impact of the disease on health-related quality of life. The effect on health-related quality of life of once-daily of cetirizine syrup 10 mg/day for 4 weeks has been studied in 544 children with seasonal allergic rhinitis in a multicenter, open, non-comparative study (2). In addition to improvements in symptom scores the authors also reported significant improvements in health-related quality of life, with good tolerability of the drug. Treatment-related adverse effects were reported in 22 subjects, of which somnolence was the most frequent problem, reported by six of the subjects. Only 12 of subjects discontinued treatment owing to an adverse effect. 

Health-related quality of life and clinical outcomes in 865 adult patients with seasonal allergic rhinitis treated with cetirizine or placebo for 2 weeks have been evaluated in a double-blind, randomized, parallel-group study (3). Cetirizine significantly improved both symptoms and health-related quality of life, while treatment-related adverse effects were comparable with those in the placebo group. 

The effects of cetirizine 0.25 mg/kg bd for 18 months have been investigated in a prospective, double-blind, parallel-group study in 817 children with atopic dermatitis aged 12-24 months (4). Dropouts and serious events, including hospitalization, were infrequent and were less common in the children who took cetirizine, although the differences were not statistically significant. Most of the adverse events were mild and were not related to medication. 

Ketoconazole raises the levels of desloratadine, emedastine, fexofenadine but as no adverse cardiac effects were seen these combinations are considered safe. No interaction occurs between ketoconazole and azelastine, cetirizine, intranasal levocabastine, and none is expected with levocetirizine. 

Etesloratadine, emedastine and fexofenadine levels are raised by ketoconazole but because this does not result in adverse cardiac effects concurrent use is considered safe. Azelastine, cetirizine (and therefore probably... 

There is a case of torsade de pointes possibly due to spiramycin with the sedating antihistamine mequitazine. The situation with erythromycin and loratadine is unclear as one study found that the combination caused a very slight increase in QT interval. Both azithromycin and erythromycin raise fexofenadine levels, but this had no effect on the QT interval, or on adverse events. Azelastine, cetirizine, desloratadine, and intranasal levocabastine seem to be free of clinically relevant interactions with macrolides. 

Fexofenadine levels are raised by both azithromycin and erythromycin but because this does not result in adverse cardiac effects concurrent use is considered safe. Azelastine, cetirizine (and therefore probably its isomer levocetirizine) desloratadine and levocabastine seem to be free from clinically significant pharmacokinetic interactions, and have no cardiac effects, and so may therefore provide suitable alternatives if a non-sedating antihistamine is needed in a patient taking macrolides. 

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