LORATADINE AND TERFENADINE IN PERENNIAL ALLERGIC RHINITIS - TREATMENTOF NONRESPONDERS TO THE ONE DRUG WITH THE OTHER DRUG

The efficacy of loratadine and terfenadine in perennial allergic rhini tis was evaluated in a double-blind, selected cross-over study consist ing of two phases. During the first phase, 76 patients with perennial allergic rhinitis, 8-67 years old, were included in the study. Of thes e, 41 patients received loratadine 10 mg daily, and 35 patients receiv ed terfenadine 60 mg twice daily, for 2 weeks. According to symptoms a nd side-effects, 32 patients were classified as responders to loratadi ne, and 28 patients as responders to terfenadine. All observed symptom s were significantly reduced in both treatment groups, but with no sig nificant differences between the two groups. Side-effects were few and mild. In patients with normal IgE, loratadine was significantly super ior to terfenadine in relieving nasal secretion, whereas terfenadine w as significantly superior to loratadine in relieving nasal congestion. In patients with increased IgE, patients treated with loratadine show ed significantly greater reduction in sneezing than patients treated w ith terfenadine. A positive correlation between total IgE and reductio n in overall symptoms was found for patients treated with loratadine, whereas a negative correlation was found for patients treated with ter fenadine. During the second study phase, the nonresponders received th e other drug for 2 weeks. All seven nonresponders to terfenadine respo nded to loratadine after crossing over, whereas four of nine nonrespon ders to loratadine responded to terfenadine. Nonresponders to one drug may respond to the other drug. Thus, more than one antihistamine drug should be tried in perennial allergic rhinitis if the first fails.