Double-blind comparison of loratadine (SCH 29851), astemizole, and placebo in hay fever with special regard to onset of action.

In this double-blind study, 65 patients with hay fever were treated for 14 days with either loratadine 10 mg once daily, astemizole 10 mg once daily, or placebo. On the third day of treatment loratadine was statistically superior to placebo, but astemizole and placebo showed no significant differences according to the ratings for symptomatology, efficacy, and individual symptoms. Adverse effects were minimal and did not differ between the three groups. Loratadine had a significantly earlier onset of action than astemizole with comparable efficacy and safety.