- Seasonal allergic rhinitis (SAR) and perennial allergic rhinitis (PAR) affect up to 40% of the population (depending on geographical area), and are associated with significant morbidity, socioeconomic costs and reductions in quality of life. Antihistamines are a first-line therapy, with newer nonsedating agents having superseded sedating first-generation drugs. Desloratadine is a nonsedating, nonimpairing antihistamine that is effective in relieving nasal and non-nasal symptoms of SAR and PAR, including nasal congestion. Desloratadine has a 24-h duration of action, enabling once-daily dosing and providing relief of morning symptoms. Clinical trials have demonstrated that it has no performance impairment, cardiovascular effects or clinically relevant interactions with other tested medications. This article reviews the use of desloratadine in the treatment of SAR and PAR.