A multicentric study of loratadine, terfenadine and placebo in patients with seasonal allergic rhinitis.

This multicentric study compared 14-day treatment with loratadine (Clarityne) 10 mg once daily, terfenadine 60 mg twice daily and placebo in outpatients with seasonal allergic rhinitis. Of 275 patients enrolled, 256 (87 in the loratadine group, 89 in the terfenadine group and 80 in the placebo group) were evaluable for efficacy and 266 (90, 91 and 85 in respective groups) were evaluable for safety. Investigators graded the severity of 4 nasal and 4 nonnasal signs/symptoms and investigators and patients rated overall disease condition and therapeutic response on treatment days 3, 7 and 14; patients recorded when signs/symptoms of rhinitis were relieved, as well. Hematology and blood chemistry tests were conducted before and after therapy, and patients were questioned throughout the study about possible adverse experiences. At all visits, loratadine and terfenadine were significantly superior to placebo (p less than or equal to 0.004), and the two active medications were statistically comparable, based on mean totals of sign/symptom severity scores and ratings of overall disease condition and therapeutic response. By patients' last valid visit, mean totals of sign/symptoms severity scores improved by 56% and 53% for loratadine and terfenadine groups, respectively, but exacerbated by 5% for the placebo group. Moreover, an excellent or a good therapeutic response was observed in 58/87 (67%) loratadine-treated patients and 58/89 (65%) terfenadine-treated patients, as compared to 13/80 (16%) placebo-treated patients (p less than 0.01). A total of 61/76 (30%) patients in the loratadine group and 57/78 (73%) in the terfenadine group versus 22/71 (31%) in the placebo group experienced relief within the first 3 days of therapy (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)