A novel method to assess antihistamine and decongestant efficacy.

A method has been developed to equalize as many of the variables as possible in a clinical trial to assess the response to medication in allergic rhinitis. This method was used to study the effectiveness of azatadine maleate and pseudoephedrine sulfate alone and in combination. Azatadine effectively relieved symptoms of hay fever but did not reduce nasal congestion to a significant degree. Pseudoephedrine relieved nasal congestion but did not reduce symptoms. The combination of azatadine and pseudoephedrine relieved both symptoms and congestion.