Double-blind study of cetirizine and loratadine versus placebo in patientswith allergic rhinitis

The aim of this double-blind study was to evaluate the effectiveness of cet irizine and loratadine versus placebo in patients with allergic rhinitis. T he study included a total of 90 patients suffering from moderate to severe allergic rhinitis as determined by a symptom score, with hypersensitivity t o house mites and with high IgE. The study lasted 7 weeks, including I for pretreatment, 4 for treatment and 2 posttreatment (washout). During the stu dy, each patient received either one tablet of placebo, 10 mg of cetirizine or 10 mg of loratadine daily. The evaluation was carried out by rhinomanom etry to analyze the symptoms on days 1, 15, 29 and 43. The nasal cytology w as analyzed on days 1 and 29. For statistical analysis we used the Mantel-H aenszel method and chi-square test We found that antihistamines showed good effectiveness in improving the symptomatology in patients with allergic rh initis. The improvement by rhinomanometry and by symptom scare versus place bo was good. It was concluded that both antihistamines were significantly s uperior to placebo and that cetirizine performed better in comparison to lo ratadine versus placebo, although not as statistically significant.