Comparative efficacy of terfenadine, loratadine, and astemizole in perennial allergic rhinitis.

Abstract

Nonsedating H1 antihistamines such as terfenadine, loratadine, and astemizole are widely prescribed for the treatment of allergic rhinitis. The comparative efficacy of these agents has not been thoroughly studied. We studied 14 subjects in an open-label four-way crossover trial. Patients were recruited from an outpatient allergy clinic. Inclusion criteria were documented rhinitis symptoms for at least 2 years before the study and skin-test positivity in response to perennial allergens. Each subject underwent sequential 2-week trials of each of four H1 antihistamines: terfenadine, loratadine, astemizole, and chlorpheniramine. No placebo was included. Outcome measures were subjective rhinitis symptom scores, overall efficacy scores, and concomitant pseudoephedrine use. In addition, nasal-examination scores were obtained by way of physician assessment at the end of each 2-week trial, and side effects were tabulated. Nasal-examination scores for each of the four H1 antihistamines were significantly better than the baseline scores (p < 0.05). No statistically significant differences in rhinitis symptom scores, overall efficacy scores, or concomitant pseudoephedrine use were noted. We detected no clinically significant differences in efficacy among terfenadine, loratadine, astemizole, and chlorpheniramine in the treatment of perennial allergic rhinitis.