Effect of desloratadine on the control of morning symptoms in patients with seasonal and perennial allergic rhinitis.

The symptoms of allergic rhinitis vary in severity over the course of the day and often are worse in the morning. This review focuses on data from clinical studies of the antihistamine desloratadine to establish whether it effectively controls the morning symptoms of allergic rhinitis. Studies of desloratadine in patients with allergic rhinitis that used instantaneous scoring to assess the severity of morning symptoms were selected for inclusion from published literature (peer-reviewed articles and abstracts presented at professional meetings). When administered once daily, desloratadine is effective in alleviating the morning symptoms of allergic rhinitis, including nasal congestion. Its action is sustained over the 24-hour dosing interval. A comparison of morning and evening dosing of desloratadine revealed equivalent relief of morning symptoms, illustrating that the effect of desloratadine is independent of the time of dosing. Clinical studies indicate that desloratadine is nonsedating and well tolerated, with no evidence of adverse cardiac effects. For many patients with allergic rhinitis, symptoms are most severe in the morning. To maximize the benefits for patients, pharmacologic agents used in the management of allergic rhinitis should be effective in controlling these peak morning symptoms. The sustained 24-hour action of desloratadine and its effective control of morning symptoms make it a valuable tool for improving the quality of life of patients with allergic rhinitis.