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Introduction: Loratadine, Fexofenadine and Cetirizine have been widely used for allergic rhinitis. This study aimed to examine the efficacy, onset of action and tolerability of these agents under dust mite nasal challenge.
Patients and Methods: Thirty-one allergic rhinitis patients were randomly given 10 mg of loratadine (n=8), 60 mg of fexofenadine (n=8), 10 mg of cetirizine (n=8), or a placebo (n=7) after collecting the baseline. The nasal allergen challenge was repeated every 30 min after taking medication for 4 h. Total nasal symptom score (TNSS) and secretion weight were assessed ten min after each challenge. Adverse effects were evaluated hourly. Additionally, the time points with definitive relief (relative efficacy) resoluted by treatments were analyzed.
Results: Antihistamines prevailed over the placebo at 120 min for cetirizine, 150 min for fexofenadine, and 180 min for loratadine. At certain points, cetirizine was more effective than loratadine on TNSS, secretion and congestion score. All drugs had a greater relative efficacy on TNSS than the placebo. Fexofenadine and cetirizine displayed a high relative efficacy. The incidence of adverse effect was high due to experimental procedure, however, it was similar among groups.
Conclusion: All drugs were more effective than the placebo. Cetirizine had the fastest onset. There was an ample significant discrepancy in efficacy among these drugs. Active agents and placebo equally affected the adverse events.
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