Background: The main objective of this randomized, double-blind, parallel-group, comparative study was to assess the efficacy and safety of rupatadine 10 mg (R10) and 20 mg (R20) administered once-daily for two weeks compared with those of loratadine 10 mg (L10) in the treatment of seasonal allergic rhinitis (SAR).

Methods: A total of 339 SAR patients were randomized to receive R20 (111 patients), R10 (112 patients) or L10 (116 patients). The main efficacy variable was the mean total daily symptom score (mTDSS) based on the daily subjective assessment of the severity of
rhinitis symptoms - rhinorrhea, sneezing, nasal itching, nasal obstruction, conjunctival itching, tearing and pharyngeal itching - recorded by patients.

Results: The mTDSS was significantly lower in the groups treated with R20 (0.80 + 0.46) and R10 (0.85 + 0.52) than in the group treated with L10 (0.92 + 0.51) by protocol analysis (p=0.03) but not by intention-to-treat analysis. The secondary variables used to
assess efficacy (mDSS, DSSmax, CSS and TCSS) also showed significantly milder symptoms in patients treated with R20 and R10, particularly in sneezing and nasal itching. All treatments were well tolerated and no serious adverse events were recorded. Headache was the most frequent non-serious adverse event, and these did not show significant differences between treatments at similar dose levels. Somnolence was more frequent in R20 than in the other two groups.

Conclusions: The present results suggest that rupatadine 10 mg a day may be a valuable and safe alternative for the symptomatic
treatment of seasonal allergic rhinitis.

Key words: Rupatadine, loratadine, rhinitis, seasonal allergic rhinitis, intermittent allergic rhinitis, platelet activating factor, antihistamine.