A Comparison of Loratadine,a New Nonsedating Antihistamine,with Clemastine and Placebo in Patients with Fall Seasonal Allergic Rhinitis

Abstract

Loratadine is a new nonsedating long-acting H₁-antagonist which has been shown to be effective at various doses in controlling symptoms of spring seasonal allergic rhinitis. In this multicenter, double-blind, parallel study, 313 adolescent and adult patients with moderate to severe, skin-test positive, fall seasonal rhinitis were randomized to receive either loratadine, 10 mg, in the morning and placebo in the evening, clemastine 1 mg. b.i.d., or placebo b.i.d. for 2 weeks. Patients maintained daily diaries of nasal and ocular symptoms and of adverse effects. They were evaluated before and 7 and 14 days after starting treatment. The mean symptom scores on days 7 and 14 showed greater improvement with both loratadine and clemastine treatments than with placebo. The incidence of somnolence in the loratadine group by comparison with the placebo group was not statistically different, whereas clemastine caused significantly more drowsiness than did placebo. We conclude that loratadine, 10 mg, once a day is as effective as clemastine b.i.d. in decreasing the symptoms of fall seasonal rhinitis and the incidence of somnolence with loratadine is not statistically different from that with placebo.