Comparison of the efficacy and safety of loratadine, terfenadine, and placebo in the treatment of seasonal allergic rhinitis.

The efficacy and safety of loratadine, 40 mg once daily, were compared with terfenadine, 60 mg twice daily, and placebo in controlling symptoms of ragweed hay fever. The study was a randomized, multicentric, parallel-group, double-blind design involving 280 patients divided into three groups receiving either loratadine, terfenadine, or placebo for a period of 14 days in the autumn of 1984. Both loratadine and terfenadine demonstrated a statistically greater reduction in symptom score compared to placebo. They were not statistically different from each other, and there was no statistical difference in the incidence of side effects between the two drugs.